454 Thaddeus Estreicher on the 



to utilize the observations which are based on the use of 

 Bunsen's calorimeter (such as Dietericfs, supra), a method of 

 extreme value when w 7 e remember that the conclusions are 

 practically independent of thermometry. 



I have brought this matter before your notice at the request 

 of the Officers of this Section, and, while sensible of the honour 

 thus conferred upon me, I regret that they did not entrust so 

 important a task to more able and influential hands. At the 

 same time I hope that a consideration of the facts and argu- 

 ments brought forward may stimulate discussion, and thus 

 accelerate our progress on to firmer ground. 



Further individual effort will avail but little ; what is 

 necessary is the decision of some body having authority, whose 

 conclusions will command the respect and assent of the 

 scientific world. 



XXXIX. On the Pressures of Saturation of Oxygen. 

 By Thaddeus Estreicher *. 



ON account of the present tendency of science to undertake 

 different kinds of researches at very low temperatures, 

 liquid oxygen is every day more widely employed in labora- 

 tories : it gives us, it is true, temperatures a little higher 

 than liquefied air or nitrogen, but it has this advantage over 

 air, that its temperature is in exact relation with its pressure, 

 not being a mixture of gases ; and over nitrogen, that it does 

 not become solid even under the lowest pressures : it is there- 

 fore the best cooling agent. 



Accordingly, besides its theoretical importance, the deter- 

 mination of the pressures of oxygen under pressures lower than 

 one atmosphere has also a practical interest ; for if we draw 

 a suitable curve, we can directly read the temperature from it, 

 knowing the pressure under which the oxygen is boiling. 

 With a similar purpose, Prof. Olszewski has determined a 

 series of temperatures and corresponding pressures below one 

 atmosphere for ethylene f. 



The late Prof, Wroblewski has already made such mea- 

 surements for oxygen J. He determined the temperatures 

 for pressures between 160 and 20 millim., leaving the 

 temperatures corresponding to the pressures above 160 and 



* Presented to the Cracow Academy on June 4, 1895. Communicated 

 by Prof. Olszewski. 



f Rozprmoy (Transactions) of the Crac. Acad. vol. xii. p. xxvi ; also 

 Comptes Rendus, vol. xcix. p. 133 (1884). 



\ Sitzungsberichte d. Wien. Akad. vol. xci. 2. p. 705 {Monatshefte 

 filr Chemie, vol. vi. p. 243, 1885). 



