4o6 THE POPULAR SCIENCE MONTHLY. 



to the earth's surface, but in the outward direction of the radius of the 

 circle of latitude of the place ; a diagonal of a parallelograim is fre- 

 quently shorter than either of its sides ; the centrifugal force acting 

 on a particle, due to the rotation of the earth, is never more than 

 about the -^ part of the force of gravity ; the direction of the re- 

 sultant of this centrifugal force and of gravity is always very nearly 

 that of gravity ; the intensity of this resultant is always less than that 

 of gravity ; and instead of increasing with the distance from the cen- 

 ter of the earth it decreases. Perhaps these are points that make no 

 difference in the value of Mr. Green's theory ; but still they are woith 

 the consideration of any one who proposes by contraries to upset the 

 doctrines of such men as Arago, Faraday, Garnier, and Halley. 



Not even the wonderful fact mentioned by Mr. Green, that " by 

 inclosing an overflowing spring tightly, and allowing the inclosure to 

 be terminated by a tube with an opening carried to a level below the 

 fountain, the flow was increased " — not even this will overthrow the 

 principles of mechanics, as any one who ever understood a siphon 

 would know. Mr. Green says, " the flow was increased because the 

 channel was increased, and the resultant of the natural forces with it." 

 But if the resultant increases with the distance from the center of the 

 earth, then why could he not increase the flow still more by running 

 the tube to a great height above the fountain instead of below it ? 

 But even Mr. Green would hardly expect to increase the flow by such 

 means. For it is well known that by confining the water of an arte- 

 sian well to a tube in which it must rise above the ground, the natural 

 flow is rapidly diminished as the height of the tube increases. The 

 " American Cyclopaedia " says : " The flow from this Avell (at Passy, 

 two miles from Grenelle) began slowly, but on September 27th (three 

 days after striking the water) bad reached over 5,500,000 gallons per 

 day. The yield at the mouth was greatly decreased Avhen raised 

 through a tube twenty-five feet high ; a like result followed at 

 Grenelle, where the yield was 440 gallons per minute at the surface, 

 but decreased to 135 gallons when forced through a tube thirty-three 

 feet high." Mr. Green will have to charge this great decrease of flow, 

 to something besides increase of friction ; for it is easy to see that, if 

 the tube were extended up just to the point to which the water would 

 rise without flowing out, there would then be 7io friction. In fact, the 

 laws of hydraulics and hydrostatics have something to do with the 

 subject of artesian wells. 



I have already mentioned some inaccuracies of statement in Mr. 

 Green's discussion of Mr. Howell's article in " Scribner's Magazine." 

 Mr. Green, finding that the difference of level between the surfaces of 

 the water in Lakes Superior and Ontario is three hiindred and sixty- 

 five feet, becomes certain that there can be no subterranean water- 

 connection between these lakes ; for, he says, " If this channel exists 

 as supposed, the surfaces of these lakes would find a common level, 



