408 Scientific Intelligence. 



My own results were developed quite independently of the 

 earlier work, and they apply emphatically for liquids. Thy- 

 mol and toluidine were even under cooled 25° and 15° below 

 their respective melting points. My range of pressures is 

 therefore 6 or 7 times as large as that of Ramsay and Young. 

 Thus my work, supplementing the researches of the English 

 chemists, is not superfluous. Water seems to be a notable 

 exception. 



I found furthermore, that the pressure necessary to solidify 

 a substance is, cset. par., decidedly in excess of the pressure 

 (positive or negative, external) at which it again liquifies. 

 Here therefore is an exceedingly simple, and hence a type lag 

 phenomenon. Making extensive use of it, I am led to results 

 bearing directly on all lag phenomena, and beyond this on the 

 molecular structure of matter in general. Data are in hand 

 for paraffin e, naphthaline, palmitic and chloracetic acids. 



Operating above 100° C., I observed that (liquid) water at a 

 pressure of 20 atm. and a temperature of 185° attacks ordinary 

 lead glass so rapidly that in very fine capillary tubes the con- 

 tents become opaque and solid in about an hour. During this 

 action the compressibility at 185° gradually and regularly in- 

 creased to a final value (200xlO c ), about 3 times the original 

 value (77 x10 s ). At the same time the isothermal volume of 

 the silicated water decreased fully 13 per cent of its original 

 bulk. So large a contraction will probably not be unaccompa- 

 nied by rise of temperature. 



Finally, in case of mercury, the simultaneous decrements of 

 electrical resistance, r, and volume, v, due to pressure (0 to 400 

 atm.), were found to be proportional to each other. Approxi- 

 mately or/?' = 10 ov/v. This result initiates a new method 

 of attacking the above thermo-dynamic problems, and it has 

 already led ulteriorly, to results of electrical interest. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. On Colloidal Cellulose. — By treating filter-paper, previ- 

 ously purified with hydrochloric and hydrofluoric acids, or the 

 finest quality of carded cotton, carefully dried, with sulphuric 

 acid of 50° B. in the cold, Guignet has obtained a colloidal form 

 of cellulose which, when the acid has been completely removed 

 by washing, is readily soluble in pure water. To ensure a com- 

 plete removal of the acid the last washings are performed with 

 alcohol and the product is dried at the lowest possible tempera- 

 ture. Belore washing, the cellulose forms a transparent gelatin- 

 ous mass which is not affected by contact with a large excess of 



