700 Miss Agnes M. ClerTte 



their scale. They have been conducted, not for the mere purpose of 

 scoring experimental successes by liquefying intractable gases, but 

 with a view to extensive and profound investigations of the properties 

 of matter under conditions previously unattainable. The realisation 

 of these conditions, however, demands a profuse outlay of labour, 

 time, and money, to say nothing of the risks incurred through the 

 rebellion of natural forces against rigid mechanical constraint. Hence, 

 a colossal equipment, disposed of by an individual of untiring energy, 

 united to courage and inventiveness of no common order, was indis- 

 pensable for the furtherance of this important enterprise ; and nowhere 

 has the combination been rendered so thoroughly effective as in the 

 laboratory of the Eoyal Institution. Its effectiveness, however, has 

 not been due to the generosity of one benefactor alone. Many have 

 contributed to it. The munificence of the Goldsmiths' Company has 

 twice brought timely relief in financial straits ; the donations of 

 private individuals have furnished indispensable supplies, and merit 

 emphatic and grateful acknowledgment. The coincidence is note- 

 worthy that the only considerable sum received by the Eoyal 

 Institution for the endowment of research has come from a fellow- 

 countryman of its versatile and far-seeing founder. What Count 

 Eumford had begun Mr. Hodgkins designedly continued, and by 

 sharing his subsidies between the Eoyal Institution of Great Britain 

 and the Smithsonian Institution of Washington, he evidently pro- 

 posed to invite the cordial co-operation of the two great English- 

 speaking peoples for the investigation of those subjects in which he 

 was so deeply interested. 



The stage of the campaign arrived at when the Hodgkins fund 

 became available for its prosecution may be described in a few words. 

 All the known gases, except hydrogen and fluorine, had been reduced 

 to liquids in a statical condition, and of these, liquid oxygen alone 

 had refused to solidify when evaporated under diminished pressure. 

 A point of cold had been reached only 73° C. above the absolute 

 zero (— 273°), and the altered electrical and chemical relations of 

 various substances cooled to — 182° had been investigated. The 

 observed progressive decrease, with increase of cold, in the electrical 

 resistance of pure metals, seemed to betoken its total disappearance 

 near the absolute zero, while alloys lost little of their resistivity, and 

 carbon followed an inverse course of change. The curious indi- 

 vidualities, in this respect, of different metals were also noted. Thus, 

 the resistivity of iron is reduced to one twenty-third, that of copper 

 only to one-eleventh, by lowering its temperature from + 10u° to 

 — 197°, at which point an iron wire actually conducts better than 

 one of the finest copper when ordinarily warm. In the.se inquiries 

 Professor J. A. Fleming co-operated with Professor Dewar. On 

 December 10, 1891, the magnetic quality of liquid oxygen was dis- 

 covered by Professor Dewar. Other well-known properties of the 

 gas proved to be equally persistent after condensation. Liquid, like 

 gaseous oxygen, is a bad conductor of heat and electricity, while 



