Liquefaction of Gases, 303 



absolute zero of temperature, and in the experiment about 

 5 lbs. of solid ethylene were employed/' 



This I declare to be the first apparatus (Pictet's excluded) 

 made wholly of metal, being an arraugement of copper coils in 

 which liquid oxygen was made and decanted or transferred 

 from the vessel in which it was liquefied to another by means 

 of a valve and thereby rendered of use as a cooling agent. In 

 support of this assertion I call as a witness Professor Charles 

 Olszewski himself, who states in the Philosophical Magazine, 

 February 1895, p. 189 : — li In 1883, and for several years 

 following, I liquefied the gases in a strong glass tube." There 

 is no suo-oestion made that a steel cylinder and valve was 

 used by Olszewski till the year 1890, whereas four years 

 in advance I had used a much safer and better form of 

 apparatus. Have I ever suggested that Professor Olszewski 

 was anticipated, or attempted to raise any question of priority ? 



With regard to another case of priority that is claimed, I 

 find that MM. Charles Olszewski and Auguste Witkowski, 

 Membres Correspondants, presentent leur memoire " Pro- 

 prietes optiques de l'oxygene liquide," on the 3rd of October 

 1892, and, on referring to the paper, it is dated the 15th 

 July 1892, and the following footnote is added : — 



" Avant la publication de notre communication MM. Liveing 

 et Dewar out fait connaitre (Phil. Mag. aout 1892) les 

 resultats de leurs recherches sur la refraction des gaz 

 liquefies." 



But Professor Olszewski is not satisfied by a reference to 

 published papers, he includes unpublished ones as well, in 

 order to include the study of chemical action at low tempera- 

 tures as having been originated by him. The folio win o- 

 extracts from a well-known Continental Journal of what I 

 had done in 1885 may induce him to produce his priority 

 claim in a definite shape. I challenge him to produce any 

 reference to antecedent work in this subject. 



Extract from Moniteur Scientifique, vol. xv. (1885), 

 p. 1134 :— 



" Sur les Solutions d'Ozone et Taction chimique de POxygene 

 liquide. Par Professor Dewar. 



" Dans cette communication, le professeur a donne la 

 description de l'appareil et de la methode dont il s'est servi 

 pour liquefier les gaz tels que l'oxygene, et apres avoir dis- 

 cute les conditions requises pour le succes de la conversion 

 des gaz dits permanents en liquides, il a rendu compte de 

 plusieurs experiences faites avec foxy gene liquide. A — 130° 



