1864.] 



Prof. Guthrie on Drops. 



455 



cohesion of the water, by asserting its own cohesion, by increasing the 

 gravity of the liquid and thereby determining an earlier separation of the 

 drop, and, in this particular case, by the chemical affinity of the solid to 

 the liquid, and the probable formation of hydrates. It is seen that these 

 influences cause an irregularity in the diminution of the size of the drop 

 as it acquires more solid matter. In fact, it is only when the liquid has 



the considerable strength of | that the diminution in drop-siz^ becomes 



8 



continuous. 



In fig. 2, C shows graphically the relation between drop-size and strength. 

 The abscissae represent the strengths of the solution progressing in geometric 



Fig. 2. 



ratio; the ordinates show the corresponding comparative drop-sizes. It 

 may be remarked that the curve C bears a striking resemblance to the 

 curve A, as though increase in solid constituent produced a similar effect 

 upon the drop-size as increase in the time-interval on the drops of a 

 homogeneous liquid. We may also notice the great difference in size between 

 a drop of water and a drop of oil under the same conditions. From 

 Table IV. we find that a drop of oil of specific gravity -9195 has the weight 

 •05986 when ^^=2". Hence the comparative sizes of the two are, — 



. Radius of Comparative 

 ^ • sphere. ' sizes. 



Water 2" 22-1 mm. 28° C. 0'18517 



Oil 2" 22-1 mm. 29°-29°-4 C. 0-06510 



Or a drop of water is nearly three times as large as the drop of oil, the 



only difference in the circumstances being that the oil was 1°-1°'4 C. 



warmer. We shall have to study this point more especially hereafter. 

 On account of the chemical union which takes place on dissolving Ca CI 



in water, it would be useless to give the absolute strengths of the various 



solutions. 



VOL. XIII. 2 L 



