XXviii SIXTH REPORT — 1836. 



of those curious observations on the Quantities of Rain falling at differ- 

 ent elevations, which had formed the subject of two preceding commu- 

 nications published in these Transactions. 



In the first series of these it had been shown by Professor PhiUips 

 that the difference between the quantities of rain that fell depended on 

 two conditions — 1st, the height, and 2ndly, the temperature ; the for- 

 mer circumstance determining the ratio of the difference between the two 

 stations, and the latter its amount. 



In the second series he showed that the ratio likewise varied at dif- 

 ferent seasons. 



The present or third series presents us with a formula for expressing 

 these variations, and points out its correspondence with the observations 

 made. 



That the quantity of rain which falls should be greater at lower than 

 at higher elevations, is a result which, though at first sight it may ap- 

 pear paradoxical, is quickly perceived to harmonize with the fact, that 

 drops of rain descend from a colder to a warmer atmosphere, and con- 

 sequently condense a portion of the aqueous vapour which exists sus- 

 pended in the lower strata. But that the rate of increase should actually 

 be found reducible so nearly to a mathematical formula, is certainly far 

 more than could have been expected, and its successful accomplishment 

 is calculated to give us hopes that other meteorological phenomena, 

 which seem at present so capricious as to baffle all calculation, may at 

 length be found reducible to certain fixed principles. So far as relates 

 to the rain that falls at York, the results are regarded by Professor 

 Phillips as sufficiently complete, but he strongly urges the advantage of 

 instituting in other spots selected in different parts of the Idngdom si- 

 milar observations, which, if executed simultaneously, would mutually 

 illustrate each other, and be likely to throw much additional light on 

 the theory of rain, and on the distribution of vapour at different 

 heights. 



An important practical paper has been published in our Transactions 

 of this year by Mr. Eaton Hodgkinson, on the effect of impact upon 

 beams. It is a continuation of some researches which he communicated 

 at the preceding Meeting, on the collision of imperfectly elastic bodies. 

 In these experiments he had laid down the general principles relating 

 to the collision of bodies of different natures, and had obtained amongst 

 other results the following, — namely, that all rigid bodies possess some 

 degree of elasticity, and that amongst bodies of the same class the hard- 

 est arc generally the most clastic. 



It remained to be seen whether this difference in elasticity influenced 



