The Birmingham age-herald., 1910-11-04

From the New York World.
 At the College of the City of New York
 the other day professor told how he had
 picked up Old Mother Earth, dumped her on the scales and weighed her. As a mat ter of fact, weighing is a misleading
 word to apply to such a scientific achieve
 ment, because the earth doesn't weigh
 anything in the sense in which you would
 say that your weight Is 14o pounds or
 whatever 1t may be.
 Your weight Is the force with which the earth pulls you toward it. and, of course,
 the earth couldn't be said to pull itself to- ward itself. What is really meant is what all the rock and earth and water in the globe would weigh if they could be brought out to the surface and meas ured
 For instance, we know the size of this planet, so we know how many gallons Of
 water could go into the space 1t occupies. Well, all the gallons would weigh just
 about 1.O00, ,0o0, ,O0O, ,O0O 100000 tons. One
 One billion billions of tons Now the earth isn't made of water only, but of
 rocks and metals and sand and a thou
 sand other things. How many times heavier would it be when all these are allowed for. To use the scientific word, what is the density of the earth. | Some scientists have tried to find out by going very high up into the moun- tains. where bodies don't weigh the same as on the surface. Weight being the force that pulls you to the earth, some of the
 weight is due to the part of the earth | close to you and some to parts further away By measuring on the top of the mountain and at the bottom the scientists could see how much of the total was due to the portion of the planet close at hand l-i. e., the mountain. Then by elaborate calculation they figured how many times bigger the rest of the globe must be, and surveyors and geoogists told them how much the mountain itself weighed.
 Still another scheme is to hang a plumb bob up on one side of mountain. The mountain will pull the plumb-bob little out of the perpendcular-a little toward itself. This was the method In the Sohichallion experiment. It was found that Schichallion, which is mountain in Scotland, pulled the plumb-bob F seconds out of plumb--12 seconds and 1-30 part of
 a degree, and you need something better than the naked eye to see defection of even one degree. From this the scientists deduced that if the earth was 14-5 as dens all through the mountain 1t would weigh l. 4-5x21a-41k times as much as water. AS
 a matter of fact, the enormous pressure inside the earth makes 1t much denser in the middle When correction was made for this the figure AZ was raised to 1-3, giving fiA thousand three hundred bil-
 lion billion tons, $500, ,0O0 O00 900 o00 COG, 000. All the methods agree fairly well. They all place the weight of the material of which the earth is composed at between five and six times the weight of water. Closer than that the scientists do not
 agree and you can take your pick. a trifle of a couple of hundred billion tons will never be missed.
 The best way of making such a meas urement was invented in 1795 by cele-
 brated English savant. Henry Cavendish, and it doesn't need a mountain or mine or any similar trifie that the average
 man doesn't carry around with him as a rule. In fact the apparatus can fit into