362 



Mr. A. M. Worthington. 



[June 16, 



In daboia poisoning, sanious discharges are the rule ; albuminuria 

 is always found, should the victim live any time, and after the nerve 

 symptoms pass over, the subject has to go through a period of blood 

 poisoning little, if at all, less dangerous than the primary symptoms, 

 from which he may die as late as the end of the second week. 



Lastly, the physiological properties of daboia poison undergo great 

 change by its being heated to 100° C. in solution, whereas cobra 

 poison remains unaltered. 



II. " On Pendent Drops." By A. M. WoRTHiNGTON, M.A. Com- 

 municated by Professor B. Stewart, F.R.S. Received 

 May 16, 1881. 



[Plate 7.] 



About two years ago I was led to examine the forms of pendent drops 

 of liquid by a method of great simplicity, which seems capable of 

 being used with considerable accuracy for determining the value of 

 the surface tension. 



Previous observers, so far as I am aware, have observed only the 

 weight of drops which fall, and, making this the basis of calculation, 

 have endeavoured to find the influence on the size of such drops, of 

 the rate of influx of liquid, shape of terminal, as in the case of 

 Dr. F. Guthrie,* or to ascertain the value of the surface tension of the 

 liquid as in the case of Professor Quinckef and M. Dupre.J 



Under no circumstances, however, is the weight of the drop which 

 falls exactly the weight of the volume which it is necessary to know 

 in order to ascertain the value of the surface tension, though under 

 certain circumstances it approximates thereto. Hence we find that 

 Prof. Quincke rejects this method of finding the tension, or recom- 

 mends it only where other methods fail ;§ albeit all his results obtained 

 by this method are vitiated by an assumption to which I shall have 

 occasion to draw attention. The principle of the method which I will 

 now describe is simply to project a magnified image of a drop pendent 

 from a cylindrical tube on to a screen, and there to trace its outline 

 at any required stage of its development. 



A vertical cylindrical glass tube, A, whose lower end is ground 

 truly flat and with a sharp edge, communicates by means of a bulb or 

 wider tube, B, and a piece of india-rubber or lead tubing, C, with an 

 air-tight syringe, D, some 10 or 12 feet away. For the usual syringe 

 piston a cup of mercury, E, is substituted, which can be gradually 



* " On Drops." By Dr. F. Guthrie. "Proc. Roy. Soc," vol. 13, p. 444. 

 f " Poggendorff's Annalen," vol. cxxxy, p. 621. c ' Phil. Mag.," 1869. 

 % " Theorie Mecanique de la Chaleur," p. 332. 

 § Loc. cit., p. 637, § 12. 



