326 Description of an improved Rain Gage. 



Corollary 3. The earth and planets, in their revolutionss 

 never perform complete circles or ellipses ; for the system 

 moving from E to R, during one revolution of the earth, 

 the earth cannot get back to the point E, from which it 

 started, and of course its orbit will be a spiral line. 



From the past progress of science, we may confidently 

 expect, that the time is not far distant, when new investi- 

 gations and discoveries shall not only place beyond a doubt 

 the revolution of the solar system, but also make known 

 the distance of the systfem from its grand centre, and the 

 time of its revolution. U. C. B. 



Middlebury, Ver. August 28, 1823. 



Art. XIV. — Description of an improved Rain Gage; by Mr. 

 George Chilton, Lecturer on Chemistry. 



The quantity of rain that falls in any particular district 

 being an important item in Meteorology, any improvement 

 in the instruments of observation by which that quantity 

 can be determined correctly, must be acceptable to the 

 cultivators of that department of science. In the common 

 construction of the Rain Gage several causes of error are 

 mai;ifest, which when taken separately, might be deemed 

 trivial, but whose combined effect is such as every accurate 

 observer must be desirous of avoiding. It is well known 

 that fluids undergo changes in bulk by changes of tempera- 

 ture, as well as by those of barometrical pressure ; and 

 that any mode of measuring the dimensions of a fluid, ex- 

 posed to the influence of these fluctuating causes, provided 

 it does not make due allowance for them must be erroneous. 



In addition to these causes of irregularity, the cohesion 

 of the fluid, which is necessarily connected with the meas- 

 urement by graduated rods, renders it impossible to deter- 

 mine the true height of it. 



But besides these obvious causes of inaccuracy, the fluid 

 in the common construction of the Rain-Gage, is too much 

 exposed to spontaneous evaporation. This might, in part, 

 be remedied by narrowing the neck of the funnel, but 

 here another difficulty arises : if the aperture, by which the 

 water enters the gage be too small, the funnel, in a smart 

 shower, might be filled to overflowing; by which a part of 

 the water would be lost. 



