Intelligence and Miscellaneous Articles. 235 



force the sulphate through the diaphragm ; I did not succeed in 

 doing so. In seven hours the column was lowered one sixth ; but, 

 ■what is remarkable, the stalactites were not formed ; merely a not 

 very thick and pretty compact layer of crystals of sulphate of lime 

 was deposited on the surface in contact with the sulphate solution. 

 The pressure therefore hindered the formation of the stalactites and 

 the passage of the sulphate solution into that of the nitrate. 



Some filtration-experiments were also made with defibrinated 

 blood under 150 millims. pressure of mercury, equal to that of the 

 blood in the arteries ; the filtrate consisted of serum only. 



It is to be presumed that in the arteries, under the pressure of 

 150 millims. to which the blood is subject, there must be an infil- 

 tration of serosity through the walls of the arteries in quantities 

 proportional to the variations of the pressure. It has been said above, 

 that the flow through the organic membrane distended the cells ; 

 under the empire of life nothing like this should take place, at least 

 in the normal state ; equiUbrium in the constitution of the vessels 

 must be constantly maintained. 



We have now some conception of the possible origin of exosmose: 

 it is due partly to diffusion, and partly to the filtration resulting from 

 the pressure of the column of liquid resulting from endosmose. I 

 conceive that it was hardly sensible in the experiments of Graham, 

 who operated with large surfaces aflfording but little elevation to the 

 liquid columns resulting from the endosmose. Dutrochet was right 

 in saying that exosmose transports more of salts than endosmose, as 

 exosmose results partly from pressure, which causes the liquid to 

 filter through with the salt which it holds in solution. — Comptes 

 Rendus de VAcad. des Sciences, July 8, 1872, pp. 50-52. 



ON THE ACTION OF OZONE UPON VULCANIZED CAOUTCHOUC. 

 BY PROF. ARTHUR W. WRIGHT. 



In using the Holtz's electro-machine, in the summer season it is 

 often very difficult to make it retain any considerable charge, or 

 even to keep up its action for more than a few minutes. The ebonite 

 insulators are found to have lost in a large degree their insulating 

 power, and to have become conductors to such an extent that con- 

 siderable sparks may be drawn from them at points several inches 

 distant from the metal parts supported by them, thus dissipating the 

 greater portion of the charge. This is the usual condition of things 

 when the machine, after much use, has stood for some weeks in the 

 warmer portion of the year unused. The surface of the ebonite 

 becomes hygroscopic, condensing upon itself a large amount of 

 moisture, the accumulated liquid being sometimes so abundant as to 

 trickle down in drops. 



Having noticed on one occasion that this liquid had an acid taste, 

 I was led to examine it more closely ; and the ordinary tests very 

 speedily showed it to be sulphuric acid. Its presence was a suffi- 

 cient explanation of the defective insulation. Similar deposits of 

 moisture were found upon the ebonite jackets of two induction-coils 

 some time after they had been used. 



