266 K. IKEDA 



cannot be looked upon as an improvement, for according to it the value 



of % for hydrocarbons is sometimes very considerable, while that for 



chloroform is very small. Empirically, Schiff's work is of great value, 



for whatever may be the value of ?', the capillary height h is a well 



defined quantity and can be accurately measured, and the relation 



found between capillary height and chemical composition is valid 



whether the constant is theoretically correct or not. Still from a 



strictly scientific point of view, the investigation must be deemed very 



imperfect, involving, as it does, an incorrect method of calculation. 



It is, therefore, very desirable that the matter should be investigated 



anew with an entirely different method, if possible, so as to confirm 



Schiffs work, and to remove all inaccuracies as far as practicable. The 



tube method is said to be the most accurate, still there is the drawback 



above alluded to. The plate and bubble method of Quincke is 



theoretically good, but practically the results obtained are but rough 



approximations. The drop method is not well fitted for accurate 



determinations, and the same may be said of the contact plate method 



which has been employed, amongst others by Schall, for similar 



purposes. The ring method used by Duprè and Wilhelmi has been 



taken up by Prof. Yamagawa of the Imperial University, who has given 



an expression by which the error due to hydrostatic pressure may be 



eliminated, and which has been applied to the measurement of surface 



tensions of various liquids. Timbe'ry* has used a thin platinum ring 



to investigate the influence of temperature on capillary constants. 



He gives only one determination by this method for each temperature, 



while he takes the average of several measurements by Quincke's 



method. He says that the result obtained by the former method is so 



accurate and certain that no second determination is required to 



confirm it. This is an excellent account, and my own experience 



* Wiedemann's Annalen 30 (1887) s.545. 



