TOL. XVIII.] PHILOSOPHICAL TRANSACTIONS. 6lQ 



On the Quantity of falling Rain. By R. Townley,* of Townley in Lancas he, 



Esq. N° 208, p. 6 1 . 



To collect and measure the quantity of rain, I fixed a round tunnel, of 12 

 inches diameter, to a leaden pipe, which would admit of no water, but what 

 came through the tunnel, by reason of a part soldered to the tunnel itself, 

 which went over the pipe, and served also to fix it to it, as well as to keep out 

 any wet that in stormy weather might beat against the uivJer part of the tunnel, 

 which was so placed, that there was no building near it that would give occa- 

 sion to suspect that it did not receive its due proportion of rain that fell through 

 the pipe about Q yards perpendicularly, and then was bent into a window near 

 my chamber, under which convenient vessels were placed to receive what fell 

 into the tunnel ; which I measured by a cylindrical glass at a certain mark, con- 

 taining just a pound, or 12 ounces Troy, and had marks for smaller parts also. 

 By the help of this cylindrical glass I thus kept my account of what rain fell, 

 and generally twice or thrice a day ; when I took several other observations, 

 both of the thermometer, barometer, winds, &c. what rain I found in the 

 receivers, if not more than made what was left in the cylindrical glass a full 

 pound, I again left in it ; but if there was more than that quantity I filled it 

 just to the pound mark, which I threw away, and did the like with the remain- 

 ing water as often as it would allow, still keeping an account chiefly of the 

 pounds thrown away, and noting also the parts of a pound remaining in the 

 glass ; by the help of which latter, and the parts reinaining at any time before, 

 by numbering the pounds and substracting the parts at the end, for example, of 

 one month, from the pounds thrown away, and the parts remaining at the end 

 of another, I find the quantity of rain fallen between these two times, and that 

 so as to assure me that I erred no more in the quantity of rain of another year 

 than by the mistake in the differences of the parts of a pound in the first and 

 last observation, whereas should I always write down the rain that falls between 

 two observations, I might be subject to make as great a mistake in every one 

 of them, and consequently be much more uncertain of the quantity of rain 

 fallen in many of those added together ; besides this addition is longer in per- 

 forming, and giving the quantity sought, than the method I make use of. It 

 appears that here we have almost twice the quantity of rain that falls at Paris. 



* Mr. Townley was an ingenious philosopher, and a useful contributor to the Royal Society from 

 the beginning ; but we are not informed of any memoirs of his life. His micrometer for the teles- 

 cope has been often mentioned ; and some ingenious papers of his were printed in several volumes of 

 the Philosophical Transantions, particularly relating to eclipses, to the division of a foot into many 

 thousand parts, to the quantity of rain, to the winds, the weather, the barometerl &c, 



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