Need for Precision Scientific Measurements
on Gravity Hills and Mystery Spots
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About Author                                 Contact Author
讀萬卷書    行萬里路

Home                                                              About Author                                               Contact Author
By Sing H. Lin, Ph.D., E-Mail: SINGHLIN@GMAIL.COM

Original appeared on November 14, 2012, Latest Revision on June 3, 2014

Abstract

There are hundreds of known gravity hills all over the world. These gravity hills exhibit a common strange
gravity phenomenon in that when people pours water on the paved highway slope of a gravity hill, the water
flows uphill, when people puts water bottle on the paved slope of a gravity hill, the water bottle rolls uphill, and
when people drive a vehicle on the highway to the bottom of a gravity hill, shift the transmission of the vehicle
to the neutral gear and release the brake, then the vehicle rolls uphill on its own without engine power.

Oregon Vortex in Oregon and several other similar Mystery Spots at other locations also show very strange
gravity mysteries. For many years, many visitors have been enjoying the thrill of such strange experience on
gravity hills and in those mystery spots, but most people dismiss such well known strange gravity phenomena
as due to the illusion in human perception. Some people have also done some measurements and tests and
claimed that their measurements proved that the strange phenomenon on gravity hills are due to illusion.
However, my careful examinations indicate that these existing measurements have serious defects and are not
valid proof for the illusion theory. Furthermore, there are six independent sets of evidences indicating that such
strange gravity phenomena are real and are not be due to illusion.

The main purpose of this article is to present several possible precision scientific methods of measurements
that may be done on these gravity hills, mystery spots and their conjugate points on opposite side of the earth
surface (A) to detect the abnormal gravity in these mystery spots, on those gravity hill and their conjugate
points, (B) to prove that the gravity is abnormal in those mystery spots and on those gravity hills, (C) to
conduct precision measurements on the small scale structure of the abnormal gravity vector at these gravity
hills and mystery spots, (D) to prove that the human perceived top of the gravity hill is indeed higher than the
human perceived bottom of the gravity hill, thereby, proving that gravity hill phenomenon is not due to illusion in
human perception.

These new ideas of scientific tests on gravity hills originate from several scientists and engineers in recent few
years through face-to-face discussions or e-mail  correspondence with me after the publication of my first
article on gravity hills on my Travelogue website in January 2007. This article is an open call for help from
experts with relevant expertise and necessary resources to carry out such precision scientific measurements
on gravity hills and in mystery spots.  Such measurement results may represent a major breakthrough in the
cutting edge of science and may open up many new and important windows of opportunities at hundreds of
known gravity hills and mystery spots on earth surface for scientists to conduct more detailed, in-depth  and
close-up investigations of the dark matters that science still does not understand well yet.

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This web page first appeared on my Travelogue website on November 14, 2012. Most recent update of this
web page was on June 3, 2014. As of June 3, 2014, this web page has been accessed 369  times by my
friends and strangers all over world.
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Table of Content

1. Introduction and Major Issues of Gravity Hills and Mystery Spots

2. Detection of Abnormal Gravity in Mystery Spots

2.1. Detection of Abnormal Gravity by Strange Behavior of Land Survey Instrument

2.2. Test of Repeatable Strange Behavior of Land Survey Instrument at Michigan Mystery Spot

2.3.  Detection of Abnormal Gravity at Several Other Known Mystery Spots

2.4. Detection of Abnormal Gravity at Many Other Known Gravity Hills

2.5. Precision Measurement of Small Scale Structure of Abnormal Gravity on Mystery Spots and
Gravity Hills

2.6. Precision Measurements of Body Weights of Two Persons When they Switch Positions in
Demonstration of Gravity Mystery in Mystery Spot

3. Some Additional Methods to Detect Abnormal Gravity at Gravity Hills

3.1. Repeated Land Survey Measurements with Theodolite moved from Location to Location

3.2. Gyroscope

3.3. Measure Elevation Angle of North Star or Other Celestial Objects

3.4. Measure the Length of the Shadow of a Plumb Line at Multiple Locations

3.5. Laser Beams Pointing Vertically

3.6 Use a Powerful Precision Telescope to compare the Plumb Line on a Gravity Hill to Other Plumb
Lines at Several Different Locations

4. Precision Measurement of Elevations of The Top and The Bottom of Gravity Hill

4.1. Surveyor Grade GPS Measurement System with Multiple GPS Comparator Receivers Linked by
Radio and a Computer.

4.3. Laser Ranging

4.4. 3-D Photography

5. Concluding Remark

6. Technical Background of the Author of This Web Page

Appendix A – Some Well known Gravity Hills for Measurements

Appendix B - Some Known Mystery Spots for Measurements

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1. Introduction and Major Issues of Gravity Hills and Mystery Spots

The strange gravity phenomena on hundreds of gravity hills and on several mystery spots on earth surface are
described on my two web pages at:

http://
www.shltrip.com/My_Personal_Experience_on_a_Gravity_Hill.html

http://www.shltrip.com/My_Personal_Experience_in_a_Mystery_Spot.html

Many people simply dismiss such strange gravity phenomena and gravity mysteries as illusion in human
perception. Some people have also done some measurements and claimed that they have proved that these
strange gravity phenomena are due to illusion in human perception.

However, my careful examination indicates that those measurements have serious defects and are not valid
proof for the illusion theory as explained in the first website listed above.  Six sets of preliminary independent
evidences against illusion theory are also described in Sections 1.1, 2.3, 3 and 4 in the first web page listed
above.

Therefore, more rigorous scientific measurements need to be done on gravity hills and mystery spots to
determine (a) the true nature of such strange gravity phenomena and gravity mysteries and (b) the source of
such abnormal gravity.

Several possible more rigorous scientific methods of measurements on gravity hills and in mystery spots are
described in the following. This article is an open call for help from experts with relevant expertise and
necessary resources to carry out such precision scientific measurements on gravity hills and mystery spots.

2. Detection of Abnormal Gravity in Mystery Spots

2.1. Detection of Abnormal Gravity by Strange Behavior of Land Survey Instrument

Three surveyors discovered the Mystery Spot at 150 Martin Lake Road, St. Ignace, Michigan, USA 49781 as
stated on
its website: "In the early 1950’s, 3 surveyors named Clarence, Fred and McCray came from
California to explore the Upper Peninsula. They stumbled across an area of land where their surveying
equipment didn’t seem to work properly. For instance, no matter how many times they tried to level their
tripod, through the use of a plum-bob or level, the plum-bob would always be drawn far to the east, even as
the level bubble was reading level." In other words, such repeated effort of these three surveyors and their
survey instrument detected that the gravity in that particular area is so abnormal that their land survey
instrument could not function properly.

The difficulty of the three surveyors on their survey instrument at Mystery Spot at St. Ignace in Michigan
provides an important hint that the gravity vector of the abnormal gravity at that special mystery area has small
scale structure in that the direction of gravity vector can change substantially in the small scale distance of one
or two feet. When the level bubble in the survey instrument on top of the tripod indicates achieving level after
the necessary fine tune screw adjustments on the instrument, the plum-bob hanging below the instrument
would always be drawn far to the east, thereby, contradicting the level indication by the level bubble on the top
of tripod. This means the gravity vector changes its direction substantially within one or two feet of distance
between the top of the tripod vs. the plum-bob hanging down from the top of tripod.

In other words, the gravity field and vector produced by a large source of gravity such as the earth is usually
very uniform over very large area of many miles. The direction of the normal gravity vector of the earth do not
change its direction in a small scale distance of one or two feet. In most regular places, the gravity is normal in
that the gravity vector is pointing vertically straight down to the center of earth and the direction of the normal
gravity vector do not change in a small scale distance of one or two feet. In most regular places, when the
bubble level on the top of tripod is adjusted and achieved level, the plumb-bob should hang straight down
between the three legs of the tripod indicating the consistent directions of the normal gravity vector at the top
of the tripod and along the plumb-bob hanging down between the three legs of the tripod. The plumb-bob with
a pointer at the bottom of the string is critical to center the position of the land survey instrument accurately.

It requires a very compact small source with very high mass density of abnormal gravity to be able to produce
a strong and abnormal gravity vector that can change its vector direction substantially in the small scale
distance of one or two feet. Therefore, the strange behavior of the land survey instrument described above is
a sensitive device to detect the small scale structure of such abnormal gravity at such special location of the
Mystery Spot in Michigan.

2.1.1. Asymmetrical Pendulum in Mystery Spots

In those well known Mystery Spots, usually there is a Mystery House. Inside the Mystery House there is a
pendulum (i.e., a heavy dead weight) or a swing set hanging freely down from the ceiling by a chain or a cable.
A mystery in the behavior of such pendulum is that its swing is asymmetrical. It is easy to push the pendulum
to swing in certain direction, but it is very hard to push the pendulum to swing in the opposite direction.
Therefore, it is an asymmetrical pendulum.

From my view point, the reason for such asymmetrical swing behavior of the pendulum is due to the existence
of a strong horizontal component of gravity pulling the pendulum toward the location of the compact sized
source of gravity. Therefore, such asymmetrical swing behavior of the pendulum is another confirmation that
the gravity in such Mystery Spot is abnormal.

I visited the Mystery Hill in North Carolina on January 15, 2014. When I was inside the Mystery House in that
location, I felt a very strong horizontal gravity pull. The horizontal gravity pull was so strong that I had to hold
on to the guard rail on the side of the Mystery House to be able to maintain my balance in standing upright.

2.2. Test of Repeatable Strange Behavior of Land Survey Instrument at Michigan Mystery Spot

It is important and highly desirable for one or more teams of experienced land surveyors to go to the location
of Michigan Mystery Spot to repeat such experiment to make sure that such strange behavior of land survey
instrument in this Mystery Spot in Michigan observed in 1950's is repeatable and such strange behavior of land
survey instrument is a reliable method to detect abnormal gravity at such special location. Such repeated
experiments is an important step to prove that the gravity in this Mystery Spot in Michigan is indeed abnormal.

The typical land survey instrument will show the strange behavior described above only when the instrument is
very close to the location of the very compact small source with very high mass density of the abnormal
gravity. It may take some effort to repeat the land survey instrument test at several locations inside the well
known zone of the Mystery Spot in order to find the correct small area where the land survey instrument will
show that strange behavior when it is very close to the very compact small source of the abnormal gravity.

2.3. Detection of Abnormal Gravity at Several Other Known Mystery Spots

The next step is to repeat such experiment of land survey instrument at Oregon Vortex in Oregon, at Mystery
Spot in Santa Cruz, California and at several other Mystery Spots described in Appendix B below. Such
experiments can prove that the gravity at all these well known Mystery Spots are abnormal with the similar
small scale structure and are detectable by the strange behavior of the land survey instrument. Such measured
strange behavior of land survey instrument is a strong proof that the gravity at all these well known Mystery
Spots are abnormal and the observed gravity mysteries are real and are not due to illusion in human
perception.

2.4. Detection of Abnormal Gravity on Many Gravity Hills

The next step is to repeat such experiment of strange behavior of land survey instrument at many well known
gravity hills all over the world. Some sample locations of well known gravity hill as candidates for such
experiment are listed in Appendix A below. Such experiments on gravity hills may take more effort because the
typical length of gravity hills is several hundred feet and the location of the compact sized dark matter with
extreme high mass density may be or may not be exactly on the paved road of the gravity hill. It may take
some more searching effort in that general area to find the correct small area where the land survey
instrument show the strange behavior (described in Section 2.1) when the land survey instrument is very close
to the compact sized dark matter with extreme high mass density.

Such experiments may prove that the gravity on all those hundreds of well known gravity hills all over the world
are abnormal and are detectable by the strange behavior of the land survey instrument.

2.5. Precision Measurement of Small Scale Structure of Abnormal Gravity in Mystery Spots and on  
Gravity Hills

It is desirable to have precision instrument(s) that can measure both the strength and the vector direction of
the abnormal gravity vector as a function of location/distance in those known mystery spots and many known
gravity hills. Such measurements can obtain accurate information on the spatial distribution and small scale
structure of abnormal gravity vector in the mystery spots and along the gravity hills. Such precision data can  
enable scientists to make more accurate determination of the size, the shape and the mass density of the
source (dark matter) of such abnormal gravity in those mystery spots and on those gravity hills. It enables
scientists to investigate some characteristics of the dark matter more closely and more precisely.

2.6. Precision Measurements of Body Weights of Two Persons When they Switch Positions in
Demonstration of Gravity Mystery in Mystery Spot

As explained in Section 5.2 of the second web page listed above, a possible second mechanism for causing  
the relative height to change so much when the two person switch their positions in the demonstration of
change of height in mystery spot is that the strengths of the abnormal gravity at those two standing positions
are vary different due to their different distances to the compact sized dark matter with extreme high mass
density. Such difference in the strength of abnormal gravity at those two standing positions will show up as
difference in body weight when the demonstrator switch from one standing position to another position.

As described in Section 5.2.1. in the second web page listed above, N.Nelson and I.Shnaper had conducted an
experiment in the Mystery House in Oregon Vortex and concluded that the net strength of gravity at that
particular location is 10% less than that of normal gravity at most regular places. This implies that the compact
sized dark matter may affect the body weight of a people in Oregon Vortex by as much as 10% depending on
the distance between the person and the location of the compact sized dark matter.

Therefore, it is important to make precision body weight measurements when the person (demonstrator)
switch from one standing position to another standing position. If the measurements indeed show that the body
weight of the person changes substantially when the person switch his/her standing position, such results can
confirm that the second mechanism is an important contributor, in addition to the tilted ground, to the mystery
of change in hight when the two persons switch their standing positions.

On the other hand, if such body weight measurements show no change in body weight when the person switch
the standing position, then such measurement results indicate that the second mechanism is negligible and only
the tilted ground is the main contributor to the mystery of change in height when the two persons switch their
standing positions.
3. Some Additional Methods to Detect Abnormal Gravity at Gravity Hills

This section describes some additional methods that may be used to detect abnormal gravity at many gravity
hills.

3.1. Repeated Land Survey Measurements with Theodolite moved from Location to Location

The typical land survey measurement is based on the reference horizontal plane established by a spirit bubble
(water or alcohol bubble) in the theodolite (or the Transit). Since the gravity hill is expected to have abnormal
gravity force to tilt this reference horizontal plane, then the measured relative height, H, between the top and
the bottom of the gravity hill is not constant but will depend on how much this reference horizontal plane is tilted
as illustrated in Figure 1 and Figure 2 on my first web page in Section 1 above. Therefore, the key idea is to
repeat the land survey measurement on the relative height, H, several times with theodolite of the land survey
instrument being moved among several locations with some locations on the gravity hill and some other
locations reasonably far away from the gravity hill. I expect that the measured relative height H from these
multiple locations are not the same and especially, those measured with theodolite on gravity hill will differ
substantially from those measured with theodolite located reasonably far away from the gravity hill. It is
expected that the measured H is positive when theodolite is located reasonably far away from gravity hill but
becomes negative when theodolite is located on the gravity hill because of effect of abnormal gravity on gravity
hill. Such significant variations in measured H is a detector of abnormal gravity on the gravity hills.

This idea of doing land survey measurements with theodolite (or Transit) located at multiple locations on and
reasonably far away from gravity hill was suggested by Warren Gifford in New Jersey through our e-mail
correspondence.  

3.1.1. Impacts of Cluster of Gravity Hills on Selection of Measurement Locations

Some gravity hill areas has a cluster of two or more nearby gravity hills separated by about 0.5 to 2 miles. The
existence of possible several unknown gravity hills in a cluster of gravity hills near a known gravity hill may
pose a serious challenge on how to select the suitable "normal" location(s) for the theodolite where the gravity
is expected to be normal in the sense that the gravity vector is pointing vertically straight down. However, the
appearance and disappearance of the strange gravity phenomenon when one moves from one gravity hill to
another nearby gravity hill indicate that there are substantial variation in gravity vector in such area of cluster of
gravity hills. The effects of such variations in gravity vector probably will show up in the results of multiple
location measurements if the measurements are done on reasonably large number of locations spread out in
such area.

3.2. Gyroscope

A gyroscope has a spinning wheel (flywheel) or a spinning disk supported on a pair of gimbal rings mounted on
axes at right angles to each other so that the spinning wheel/disk will remain suspended in a horizontal plane
between them regardless of any motion of its support structure. Many sample images of gyroscope can be
seen at the following website:

Click here to see many photos of gyroscope

The spinning wheel or spinning disks in a gyroscope is spinning at high speed generating a large angular
momentum. The strong inertia of such large angular momentum enables the gyroscope to maintain a very
stable orientation/direction. A gravity force pulling the entire gyroscope structure up or down or side way will
not affect the stable orientation of the gyroscope. It is only a strong torque to try to rotate the gyroscope may
affect the stable orientation of the gyroscope and produce the precession motion (gyration) of the gyroscope.

Therefore, a gyroscope with a stable orientation may serve as a stable reference to check if the horizontal line
or horizontal plane indicated by the water bubble in carpenter level or in theodolite is affected by the possible
abnormal gravity on the gravity hill or not. For such measurements, one may put a gyroscope and a carpenter
level (or a plumb line) together and possibly align their orientations at a given location. Then move such paired
instruments together to several different locations with some locations on a gravity hill, and some other
locations reasonably far away from the gravity hill. And one carefully observes and records the relative
orientations of the gyroscope and of the carpenter level at these several different locations. The key result that
we are looking for in such measurements at multiple locations is that the relative orientation of the gyroscope
and of carpenter level will varies from location to location if some of the locations have abnormal gravity.

In a face-to-face dinner discussion on the topic of gravity hill in Silicon Valley in California, Alan Ritchie in
Silicon Valley suggested the use of gyroscope as a stable orientation reference for detection of abnormal
gravity on gravity hills.

3.2.1. Required Accuracy of the Measurement Instruments

The elevation difference between the top and the bottom on many gravity hills is in the order of 20 to 30 feet.
The length of many gravity hills is about 500 to 1,000 feet, some are longer and some are shorter. (Although I
have heard of an exceptionally long gravity hill of miles, that is rare among hundreds of known gravity hills.) In
other words, the same highway beyond the length of about 1,000 feet of the gravity hill, does NOT exhibit the
strange gravity phenomenon any more. Therefore, the elevation angle of the top of gravity hill as viewed from
the bottom of the gravity hill relative to the local horizontal plane is in the order of 2 degrees. Therefore, the
sensitivity and the accuracy of the angular measurements using the gyroscope and carpenter level must be 0.2
degrees or better to be able to detect and measure accurately such small variations in angle. Therefore, the
investigators should take care to ensure that the measurement instruments have such necessary accuracy and
sensitivity in measuring the possible variations of the tilt angle in the horizontal line indicated by the carpenter
level when the pair of the instruments is moved from location to location in such multiple-location precision
measurements.

3.3. Measure Elevation Angle of North Star or Other Celestial Objects

North Star (Polaris) is approximately aligned with the Earth's Axis of Rotation. The position of North Star in the
sky is very stable and is well known to people familiar with astronomy. In doing measurement, the location
(latitude and longitude) of the measurement can be determined precisely by certain methods (such as GPS
receiver). The theoretical elevation angle of the North Star relative to the true local horizontal plan is the known
latitude of that particular location plus 90 degrees. The known theoretical elevation angle can be compared to
the elevation angle of the North Star as measured by a Sexton or a theodolite which is centered and aligned by
the typical use of the spirit bubble and the plumb line. If the local gravity is normal such that the local gravity
vector is pointing vertically straight down, then the measured elevation angle of the North Star will be identical
to the theoretical elevation angle ( i.e., latitude of the location plus 90 degrees). On the other hand, if the local
gravity vector is NOT normal and is tilted slightly from the true vertical direction, then the measured elevation
angle of North Star will differ slightly from the theoretical elevation angle. Such difference is a good indication
that the local gravity vector is abnormal and is NOT pointing vertically straight down. These angle
measurements must be very precise because the expected possible variation is only about 2 degrees or less.
This method to detect abnormal local gravity works well if the tilted gravity vector is in the same vertical plane
of the meridian of the location of measurement.

But if the tilted local gravity vector is not tilting in this vertical plane of meridian of the measurement location,
the method described in the paragraph above may not be able to measure the tilting angle accurately. Then
the method may have to be supplemented by the following more elaborate method.

The idea is to use several sets of Sextant (
六分儀) or theodolite at several locations to measure the elevation
angles simultaneously of other selected celestial object (e.g. Sun or moon or other star) relative to the local
horizontal plane established by the spirit bubble and or plumb line. Some of the measurement locations are on
the gravity hill and some are reasonably far away from the gravity hill. These angle measurements must be
very precise because the expected possible variation is only about 2 degrees or less. The key result that we
are looking for is that the measured elevation angle of a selected celestial object varies from location to
location if the gravity vector at some of the locations is abnormal.

However, we do not know accurately which direction the potential abnormal gravity vector is tilted. Therefore,
we may have to repeat the measurements described in this section several times with different positions of the
selected celestial object in the sky. The direction of the road of the gravity hill may provide an approximate
indication on which direction the abnormal gravity vector is tilted.

This idea of measuring the elevation angle of North Star or other celestial object was suggested by Edmond
Hong and by Chih Kwan Chen separately in New Jersey during my lunch conversation with each of them
separately on this topic.

3.4. Measure the Length of the Shadow of a Plumb Line at Multiple Locations

The idea is to use the length of shallow of a plumb line to detect abnormal gravity on a gravity hill. In this
method, one sets up plumb lines and their associated local horizontal planes, as established by the local spirit
bubble, at multiple locations, some on the gravity hill and some reasonably far away from the gravity hill. On a
sunny day, measure the lengths of the shadows of these plumb lines as projected on the corresponding local
horizontal planes at these multiple locations simultaneously and compare these measured lengths of shadows.
If the gravity vector on the gravity hill is tilted relative to those on  locations far away from gravity hill, then the
length of shallow measured on the gravity hill will be different from those measured on locations far away from
gravity hill.

The set up of these equipment and the measurements of the lengths of shadows must be very precise
because the expected possible variation in the local horizontal plane is only about 2 degrees or less. The key
result that we are looking for is whether all these measured lengths of shadows are identical or not.

This idea of measuring the lengths of shadows of multiple plumb lines to detect abnormal gravity vector was
suggested by Professor Brian Chen during a dinner conversation in New Jersey.

3.5. Laser Beams Pointing Vertically

The idea is to set up several laser beams at several locations, each laser beam is pointing vertically straight up
relative to the local horizontal plane established by a local spirit bubble. Some of these locations are on the
gravity hill and some are reasonably far away from the gravity hill. Then on a foggy day, one can see and
check if all these multiple laser beams are parallel to each other or not. Since the gravity vector on a gravity hill
is expected to be abnormal and is tilted slightly (in the order of 2 degrees) relative to those on normal locations
far away from the gravity hill. We should be able to see such difference in the vertical pointing directions of
these laser beams as a way to detect the abnormal gravity vector on the gravity hill.

The set up of these vertically pointing laser beams must be very precise because the expected possible
variation in the angles among these laser beams is only 2 degrees or less. The visual inspection of these laser
beams must also be very accurate because the expected possible variation in their pointing angle is only about
2 degrees.

The idea of using laser beams was suggested by Di Chou in New Jersey during a lunch conversation
.

3.6. Use a Powerful Precision Telescope to compare the Plumb Line on a Gravity Hill to Other Plumb
Lines at Several Different Locations

Some cameras with powerful long telephoto lenses have a mode with both vertical and horizontal grid lines as
viewed from the viewfinder of the camera. This can be useful to check if two or more plumb lines at some
distance away are parallel to each other or not. One may set up a plumb line on a known gravity hill and also
set up several plumb lines at several other locations at substantial distance (e.g., miles) away from the known
gravity hill. Then one can use such camera with powerful and precision long telephoto lens to take high quality
photos and to check if the plumb line on the known gravity hill and other plumb lines on several other locations
away from the known gravity hill are parallel to each other or not. Therefore, this may be another method to
detect the abnormal gravity vector on a known gravity hill.

Again, due to the possibility of a cluster of several nearby gravity hills with abnormal gravities, the reference
plumb line for comparison to that on the known gravity hill must be set up at several locations miles away from
the known gravity hill. Setting up just one reference plumb line at one location away from the known gravity hill
may not be sufficient because the gravity vector on such second location may not be normal either. It is
necessary to set up such reference plumb lines at multiple different locations.

Necessary Precision in such Measurement: The possible difference in the directions of these plumb lines may
be only one or two degrees and be significant for producing the strange gravity hill phenomenon. The
measurement instruments must be of very high quality and high precision with sufficient sensitivity to see
clearly such small difference in angle in the order of one or two degrees. The investigator must also be careful
and skillful to be able to determine if the observed plumb lines are parallel or not with accuracy to one or two
degrees. Many lower quality telephoto lenses are known to have some distortions of the horizontal lines or
vertical lines, especially near the edge of the picture frame. The Photo Shop and other photo editing software
programs all have well known feature to correct such lens distortion. Therefore, the telephoto lens to be used
in such measurements must be of very high quality to avoid such distortion tilting the plumb lines in the photos
taken.

The idea of this method of using powerful telescope for such measurements originates from Chih Kwan Chen
in our e-mail discussions on this subject.

4. Precision Measurement of Elevations of the Top and the Bottom of a Gravity Hill

The methods in this section are precision measurement methods of the elevations of the top and of the bottom
on the paved highway of the gravity hills to see if the human perceived top of the gravity hill is really higher than
the human perceived bottom of the gravity hill.

Some people have used the consumer grade single GPS received to do such measurements of the elevations
of the top and the bottom of a gravity hill. However, the measurement errors of consumer grade single GPS
receiver is much larger than the typical elevation difference of a typical gravity hill. Therefore, such
measurements using consumer-grade single GPS receiver do not have the necessary accuracy to measure
accurately the elevation difference between the top and the bottom of a typical gravity hill.

Other methods or instrument with much higher precision are necessary to measure accurately such  elevation
difference.

4.1. Surveyor Grade GPS Measurement System with Multiple GPS Comparator Receivers Linked by
Radio and a Computer.

The accuracy of elevation measurements of regular consumer grade GPS receiver is NOT good enough to
measure accurately the elevation difference, H,  between the top and the bottom of typical gravity hills.
Detailed description of such problem is in Appendix D on web page at:

http://
www.shltrip.com/My_Personal_Experience_on_a_Gravity_Hill.html

I thank Anders Pettersson and Chuck Blatchley for sending me valuable information by e-mail to help me
understand that much higher precision has been achieved in the Survey Grade, comparator type of multiple
GPS receivers. The cost of regular consumer-grade single GPS receiver is in the order of a few hundred US
dollars. But, the special surveyor grade GPS measurement system used by professional land surveyors are
much more sophisticated, costing about US$10,000 and can achieve the accuracy in the order of centimeters.
Such accuracy is very good for precision measurements of elevations on gravity hills.

Some key time-varying measurement errors in a single GPS receiver are reasonably uniform over a fairly large
geographic area for GPS receiver location. If we place two GPS receivers for simultaneous measurements
with radio link to a computer, one GPS receiver on the visually perceived lowest point on the gravity hill and
another one on the perceived highest point, a few hundred feet away, and use radio links and suitable
computer software to compare and to subtract the simultaneously measured absolute elevations from these
two GPS receivers, the common and time-varying first order large  measurement errors from these two GPS
receivers are subtracted out leaving only the real difference plus some second order smaller errors between
the elevations at these two simultaneous measurement locations. In this way, the comparator GPS with two or
more receivers can achieve much better accuracy of differential elevation in the order of centimeters and is
much better than those of single GPS receiver for measurements on gravity hills. The remaining second order
measurement errors are much smaller than the first order errors in single GPS receivers.

The idea of using surveyor’s grade GPS measurement system was suggested by Anders Pettersson and
Chuck Blatchley through e-mail correspondence.

4.1.1. Error-Combating Measurement Techniques in GPS based Measurement Systems

According to Anders Pettersson and Chuck Blatchley, even with the surveyor grade GPS measurement
system, substantial experience and care are still necessary to achieve accurate results. Experienced users of
GPS  receivers with suitable training learned to read the satellite report  screen on the GPS receiver to be
able to tell if the measurements will be good or not, judging by the number of "seen" GPS satellites, their signal
strengths and the placements of these orbiting satellites in the sky at the measurement moment. Achieving
centimeter-precision by GPS measurement with comparator multiple receivers demands that (1) the operator
takes quite a few readings and (2) have very good Survey Grade GPS measurement system, (3) especially
dual band L1/L2 Survey Grade GPS receivers which are more expensive in the order of US $10,000, (4) with
preferably minimum of eight visible GPS satellites nicely spread out in the sky, plus (5) the WAAS
augmentation system is running. Such a precision instrument would cycle in on very good precision within a few
minutes. (6) However, such accuracy will not be maintained if the GPS receivers are moving. (7) Usually the
operator needs to make several hundred readings in one place - so allowing up to 15 minutes for it to gain
precision can sometimes be necessary.

However, I have no personal experience in using such surveyor grade GPS measurement system. We hope
that companies and surveyor(s) who have such relevant expertise and resources in such surveyor grade GPS
land survey system to use such GPS measurement system for precision measurements of the elevation
difference, H, between the top and the bottom of one or more known gravity hills. Such higher precision GPS
measurements can tell if the human perceived top of a gravity hill is really higher than the human perceived
bottom or not.

4.2. Laser Ranging

In a lunch conversation, Ea-Jan Shee in New Jersey told me that the elevations of earth surface at various
point have been measured very accurately by using laser ranging method with laser ranging system on a
satellite or on an aircraft. Such precision laser-measured map of earth surface may exist in certain government
organization(s). We hope that the relevant experts in the relevant government organization(s) can help to
examine the laser ranging data to get the accurate elevations of the top and the bottom of the paved highways
on several selected well known gravity hills as listed in Appendix A. I am not familiar with such measurement
system, and do not know the accuracy of such elevation map. Again, such laser ranging data may tell if the
human perceived top of a gravity hill is really higher than the human perceived bottom or not.

In case if the existing laser ranging data does not cover any of these well known gravity hills, we hope the
relevant experts and organization(s) in this fields can help to conduct special laser ranging measurements to
obtain the accurate elevations of the top and of the bottom of the paved highways on several well known
gravity hills.

A Caution: There are existing global maps of elevation of earth surface available in public. My rough
understanding is that such global maps look smooth and very impressive and cover any point on the entire
earth surface. However, in reality, the measured data behind such global maps were measured at only some
discrete sample points with spacing of hundreds of meters between these sample measurement points,
especially in rural areas outside of major cities . Then software interpolation algorithm was used to provide the
estimated elevations of all the points between these sample measurement points by interpolation. Such
interpolated estimation cannot yield accurate elevations of the top and of the bottom of gravity hills. Using such
interpolated map can cause more confusion on the issue of whether the top of a gravity hill is really higher than
the bottom or not. It is better to use the real data measured on the top and on the bottom of gravity hills
instead of using such interpolated estimations that can cause more confusion on the issue.

4.3. 3-D Photography

In a lunch conversion, Ea-Jan Shee in New Jersey told me that there are precision 3-D photography techniques
to determine the variations in elevation of earth surface or other objects on the earth surface by taking high
resolution 3-D photos of earth surface from an aircraft or from a satellite. Again such global maps of earth
surface may exist in certain government organization(s). We hope that the relevant experts in relevant
government organization(s) can help to obtain the accurate elevations of the paved highway on the top and of
the bottom on several well known gravity hills as listed in Appendix A. I am not familiar with such technology
and do not know the accuracy of such elevation map.

5. Concluding Remark

The existing measurements that were done on gravity hills have serious defects and are not valid proof for
Illusion Theory for gravity hills. There are still no rigorous scientific measurements done on gravity hills to prove
whether the well known strange phenomenon on hundreds of gravity hills all over the world is real or is due to
illusion in human perception. On the other hand, there are six sets of preliminary evidences indicating that the
strange gravity phenomenon on gravity hills may be real and may not be due to illusion. (see Sections 1.1, 2.3,
3 and 4 in the first website listed in Section 1.1)

This new Web Page presents a collection of scientific methods for precision measurements to detect the
expected abnormal gravity on these gravity hills and in mystery spots. The ideas in this collection come from
several scientists and engineers in last few years through my face-to-face discussions or e-mail
correspondence. I hope that experts in science and engineering community with relevant expertise and
necessary resources can conduct these precision measurements on many known gravity hills and several
known mystery spots to resolve this long standing issue. The results from such measurement may represent a
major breakthrough in the cutting edge of science on the dark side of universe and may open up many new
important windows of opportunities at hundreds of known gravity hills and several mystery spots on earth
surface for scientists to conduct more detailed and close-up investigations on the dark side of universe.

6. Technical Background of the Author of This Web Page

Dr. Sing H. Lin is a retired Telecommunication engineer with technical expertise in the area of radio/wireless
communication technologies and systems. He received his Ph.D. Degree in Electrical Engineering from the
University of California at Berkeley, California, USA in 1969 and BSEE degree from National Taiwan University
in 1963. He joined Bell Laboratories in New Jersey, USA in 1969. He has 68 technical publications and
presentations in various technical journals and conferences, 3 patents, a Chinese certificate of a copyright on a
mapping table for Chinese Spelling Code.

He had been a member of the US Delegation to International Telecommunication Union (ITU) for many years in
developing the global standards and recommendations for radio/wireless communications systems including
the Third Generation (3G) mobile wireless communications systems and beyond. In 1998, this international
team of wireless technology experts, including Dr. Sing Lin, completed the development of ITU standard for 3G
mobile wireless communication system. This 3G wireless mobile system standard provides the platform that
spawned the rapidly growing smart phone industry with many useful applications attracting huge number of
users all over the world. The total global annual sales of smart phones is about 500 million units in 2011 and is
growing very fast. The smart phone industry is now moving forward into the international 4G system standard
which is also known as LTE (Long Term Evolution).

Dr. Sing H. Lin and his colleagues in the old Bell Laboratories had conducted many years of experiments on
effects of multipath radio propagation and rain attenuation on the performance of terrestrial and earth-satellite
microwave communication radio links. Such experiments and huge amount of data were collected from
numerous microwave radio links in USA and in some foreign countries such as Saudi Arabia. Results from
such  experimental data, analyses and developed theories are important for engineering microwave
communication radio links to meet performance objectives. Some of these results were published in the
following technical papers:

S. H. Lin, H. J. Bergman and M. V. Pursley, "Rain Attenuation on Earth-Satellite Paths - Summary of 10-year
Experiments and Studies," The Bell System Technical Journal, Vol. 59, No. 2, February 1980, pp 183 to 228.

S. H. Lin, "Statistical Behavior of a Fading Signal," The Bell System Technical Journal, Vol. 50, No. 10,
December 1971, pp. 3211 - 3270.

S. H. Lin, "Statistical Behavior of Deep Fades of Diversity Signals," IEEE Transaction on Communications, Vol.
COM-20, No. 6, December 1972, pp. 1100 - 1107.

By using statistical Theory of Extremes, Dr. Sing H. Lin has also developed a theory and a method to obtain
nationwide long term (25 to 50 years) distributions of rain rate at more than 200 locations in USA. Such theory
and method are published in the following technical papers:

S. H. Lin, "Statistical Behavior of Rain Attenuation", The Bell System Technical Journal, Vol. 52, No. 4, April
1973, pp. 557 - 581.

S. H. Lin, "Rain Rate Distributions and Extreme Value Statistics," The Bell System Technical Journal, Vol. 55,
No. 8, October 1976, pp. 1111 - 1124.

S. H. Lin, "More on Rain Rate Distributions and Extreme Value Statistics," The Bell System Technical Journal,
Vol. 57, No. 5, May-June 1978, pp. 1545 - 1568.

Note: The technical papers in Bell System Technical Journal (BSTJ) from 1922 to 1983 are available online as
indicated in the following BSTJ website:

http://
www3.alcatel-lucent.com/bstj/

A complete list of his 68 technical publications and presentations in various technical journals and conferences
and of his patents is in his web page at:

http://www.shltrip.com/Patent_and_Publication.html

When he was a Ph.D. student in the University of California at Berkeley, he did take and enjoyed the graduate
course on Radio Astronomy. As a radio engineer in Bell Laboratories, in New Jersey, USA, he participated in a
team project on radiometer measurements and experiments as related to satellite communication technologies.
He learned the Dickie radiometer technologies from a team of radio astronomers, including Robert W. Wilson,
in Bell laboratories at Crawford Hill in Holmdel, New Jersey.

His interest in astronomy continues from his student life through his professional engineering life and into his
retiree life. In his retiree sightseeing trips, he enjoyed touring the Very Large Array (VLA) site operated by the
National Radio Astronomy Observatory near Socorro, New Mexico and the National Solar Observatory and
Apache Point Observatory on Sacramento Peak in New Mexico, USA in February 2006. More information on
and a picture of Dr. Sing H. Lin are available at the following web page:

http://www.shltrip.com/aboutus.html

His e-mail address is: SINGHLIN@GMAIL.COM

He has retired from his professional Telecom engineer job and is living in New Jersey, USA.

********************************************************************

Appendix A – Some Sample well known Gravity Hills

There are hundreds of known gravity hills all over the world for interested experts to conduct precision
scientific measurements. Information on such known gravity hills are available on Internet. A summary is
available on MY First Gravity Hill Web Page listed in Section 1.1. above.  Some of the better known gravity
hills are listed in the following. However, please see Section 1.3. entitled "Not All Gravity Hills Are Equal" on my
first web page on Gravity Hill

http://www.shltrip.com/Magnetic_Hill.html  

about the major differences among these selected gravity hills.

A.1. Magnetic Hill at Moncton in eastern Canada

The Magnetic Hill is at northwest part of the city of Moncton in the Province of New Brunswick, Canada.
Moncton is in eastern Canada, near northeast tip of Bay of Fundy, on TransCanada Highway 2, about 1,036
Km east of Montreal and 273 Km northwest of Halifax.

Directions: Take exit 450 of the TransCanada Highway (i.e. Highway #2) for Route 126 (i.e., Mountain Road)
and follow the signs of Magnetic Hill. Phone: 506-853-3516.

Map: Click here to see Interactive Google Map showing location of Magnetic Hill near Moncton


A.2. Two nearby Gravity Hills near New Paris in south-central Pennsylvania, USA

Website of this gravity hill is at:

http://www.gravityhill.com/

Location: Junction of Gravity Hill Rd and Bethel Hollow Rd, New Paris, Pennsylvania 15554, USA

Map: Click here for interactive Google Map showing location of these two gravity hills near New Paris, PA

Map: Click here for interactive Bing Map showing location of these two gravity hills near New Paris, PA

There are two nearby gravity hills here:

Direction to Gravity Hill #1:
1.        From route 30, drive to the town of Schellsburg which is about 8 miles west of Bedford.
2.        In Schellsburg, turn north onto Route 96 (Cortland Rd.) at the one-and-only traffic light (towards the
town of New Paris). Drive about 4 miles on Rt. 96. Before you come to the town of New Paris, you'll come
upon a small metal bridge. The sides of the bridge are metal ... the road surface is paved.
3.        Turn left just before this bridge onto Bethel Hollow Road (S.R. 4016). Drive for 6/10th of a mile and
bear left at the first "Y" in the road. (Stay on the Bethel Hollow road, the "main" road).
4.        After another 1 1/2 mile, you'll come to an intersection that has a stop sign (for on-coming traffic only).
Bear right onto Gravity Hill Road (TR 539) and drive 2 tenths of a mile and look for the letters "GH" spray
painted on the road surface.
5.        Go past the first "GH" (top of hill) about 0.1 mile and stop before you get to the second spray painted
"GH" (bottom of hill). This is it, Pilgrim. You have arrived at the bottom of the Gravity Hill, watch for white
“start” (Bottom) & “end” (top) markers on road.

Another map can be seen at the following website:

http://
www.gravityhill.com/directions.html


Direction to Gravity Hill #2:
Unmarked Second Gravity Hill
There is a second, unmarked Gravity Hill, just 0.3 mile past the second, spray painted, "GH". Look for the
telephone pole with the number "69". Stop beside this pole (the bottom of Gravity Hill) and defy gravity once
again.

A.3 Electric Brae in Ayrshire, Scotland

The gravity hill known as Electric Brae in Ayrshire, Scotland is described in the following Wikipedia website:

http://
en.wikipedia.org/wiki/Electric_Brae

During the Second World War, even General Dwight D Eisenhower, who had a flat nearby at Culzean Castle,
brought visitors here to see and to experience this strange gravity phenomenon on Electric Brae.

There is more than one stretch of road known as Electric Brae, but the most famous is on the A719 (i.e., Ayr
Road), south of Dunure, not far from Ayr, between Drumshrang and Knoweside.

Map: Click here for interactive Bing Map showing location of Electric Brae

Directions for another section of Electric Brae:

From the town of Ayr take the coastal highway A719 south towards Dunure. Stop at the stone road marker,
shown on the following website:

http://
en.wikipedia.org/wiki/Electric_Brae

This gravity hill runs the quarter mile from the bend overlooking Croy railway viaduct in the west to the wooded
Craigencroy Glen to the east.

More information on this Electric Brae on the coastal highway can be seen at the following YouTube website:

http://
www.youtube.com/watch?v=MRuEUSiMalk

http://www.youtube.com/watch?v=DBSRLtLBvpA&feature=related

http://www.youtube.com/watch?v=JDhLTozHXlI&feature=related

http://www.youtube.com/watch?v=DsxrAGGcauk&feature=related

http://www.youtube.com/watch?v=5w8dMeysxaY&feature=related

A.4. Two nearby Gravity Hills near Titusville in southwest New Jersey, USA

There are two nearby mild gravity hills along Pleasant Valley Road near Titusville in New Jersey. They are
about 2 miles apart. However, the slopes of these two mild gravity hills are not as steep as that on Magnetic
Hill in Moncton in eastern Canada

Gravity Hill #1 along Pleasant Valley Road:

Location: Top of gravity hill #1 is at the junction of Pleasant Valley Road and Bear Tavern Road in Hopewell
Township, New Jersey 08560. It is about 2 miles northeast of Titusville in southwestern New Jersey. It is
about one and half mile north of Washington Crossing State Park, about 8 miles northwest of Trenton and
about 8 miles west of Princeton. This junction is also the junction of Pendinton-Harbourton Road and Trenton-
Harbourton Road, because Pendington-Harbourton Road on the east side of this junction becomes Pleasant
Valley Road on the west side of this junction, and Trenton-Harbourton Road on north side of this junction
becomes Bear Tavern Road on south side of this junction

Map: Click here for interactive Google Map showing location of top of Gravity Hill #1

The Gravity Hill #1 is along Pleasant Valley Road with hilltop at the junction of Pleasant Valley Road and Bear
Tavern Road and the bottom of the gravity hill is about 100 yards west of the hilltop (the road junction) as
shown on the Map above. There is a roadside mailbox number 244 near the bottom of the Gravity Hill #1 along
Pleasant Valley Road.

Gravity Hill #2 along Pleasant Valley Road:

Location:  Bottom of the Gravity Hill #2 is about 20 feet west of the junction of Pleasant Valley Road and
Pleasant Valley Harbourton Road. The top of the gravity hill is about 70 yards west of the bottom. There is a
spray paint sign of “Johnson” and X on the road side at the bottom of the Gravity Hill #2.

A.5. Strange Slope (怪坡) in northeast China

The gravity hill known as Strange Slope (怪坡) is near Qingshuitaizhen (清水台镇) about 35 km northeast from
the downtown of ShenYang (沈阳), which is the capital of Liaoning Province in northeast China.

Map: Click here to see Google Map showing location of this Strange Slope in northeast China

More information and photos on this Strange Slope are available at the following websites:

http://
english.cri.cn/4406/2008/01/08/1122@311974.htm

http://www.huaxia.com/lnsy/liaon_gdfq33.htm  

There are four lanes on this strange slope for visitors to experience the strange phenomenon of gravity hill.
Two lanes are for vehicles to go up and down the strange slope. The other two lanes are for people to ride
bicycles to go up and down the strange slope. A friend of mine, Peter Lu, who visited this strange slope said
that when he was going down the strange slope on a bicycle, he had to peddle pretty hard. But when he was
going up the strange slope, he did not have to peddle at all. The bicycle just rolled up the strange slope.

*******************************

Appendix B - Some Known Mystery Spots

B.1. Oregon Vortex at 4303 Sardine Creek Left Fork Rd, Gold Hill, Oregon, USA.

Map: Click here for interactive Google Map showing location of Oregon Vortex

Website: http://www.oregonvortex.com/

B.2. Mystery Spot at 465 Mystery Spot Road, Santa Cruz, California, USA.

Website: http://
www.mysteryspot.com/

B.3. Mystery Hill at 129 Mystery Hill Lane, Blowing Rock, North Carolina, USA 28605

Website: http://
www.mysteryhill-nc.com/

B.4. Cosmos Mystery Area in the Black Hills National Forest at 24040 Cosmos Rd, Rapid City, South Dakota,
USA

Website: http://
www.cosmosmysteryarea.com/

B.5. Mystery Spot at 150 Martin Lake Road, St. Ignace, Michigan, USA

Website: http://
www.mysteryspotstignace.com/

B.6. Montana Vortex at 7800 Hwy 2 East, Columbia Falls, Montana, USA 59912

Website: http://
www.montanavortex.com/

B.7. Confusion Hill - Gravity House at 75001 N. Hwy. 101, Piercy, CA 95587, Phone: 707 925-6456, on side of
hill north of Piercy and Smithe Redwoods State Reserve.

Website: http://
www.confusionhill.com/

B.8. Teton Mystery (Spot) at 9800 South US Highway 89, Jackson, WY 83001, on side of hill, near
intersection of Hwys. 89/26, 22, 189, (The tourist attraction business of Teton Mystery Spot is closed, buy
visitors may ask for permission to enter.)