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From: steve@jplgodo.UUCP (Steve Schlaifer x3171 156/224)
Newsgroups: net.physics
Subject: Re: Electric Brae
Message-ID: <571@jplgodo.UUCP>
Date: Fri, 14-Feb-86 14:01:06 EST
Article-I.D.: jplgodo.571
Posted: Fri Feb 14 14:01:06 1986
Date-Received: Wed, 19-Feb-86 08:03:52 EST
References: <736@brl-smoke.ARPA> <933@nmtvax.UUCP>
Distribution: net
Organization: Jet Propulsion Labs, Pasadena, CA
Lines: 32
Summary: how do spirit levels *prove* gravity is not amiss

In article <933@nmtvax.UUCP>, shipman@nmtvax.UUCP (John Shipman) writes:
> >    "My cousins took me to see this neat thing called the 'Electric Brae'.
> >     Have you ever heard of it?  A brae is a hill, and this one has a 
> >     peculiar property: it defies gravity!  We got over the crest of the
> >     hill, and cousin Tom put the car in neutral; now, it should have 
> >     rolled down the hill, right?  But no--the car coasted to a stop and
> >     then started backing up the hill!...
> 
> .......
>
> Has anyone visited such a spot?  I haven't, but I remember one
> of my secondary school science teachers said this was done by 
> providing erroneous vertical references.  Artifacts that everyone
> assumes are vertical, such as walls, phone poles, or conifers,
> were all bent slightly to disorient the eye.
> 
> Investigators should carry a pair of spirit levels to establish true
> vertical.  
If the claim being made is that gravity is not pulling in the *right* direction,
then the use of a spirit level at the location of interest would only *prove*
that gravity was not pulling in the *right* direction.  Rather, what is needed
in this case is to measure the slope of the ground or whatever from a location
where everyone agrees that the direction of the gravitational pull is OK.
Possibly a surveyor or a civil engineer could explain how this might be done.
Are the any such out there reading this?
-- 

...smeagol\			Steve Schlaifer
......wlbr->!jplgodo!steve	Advance Projects Group, Jet Propulsion Labs
....group3/			4800 Oak Grove Drive, M/S 156/204
				Pasadena, California, 91109
					+1 818 354 3171