192 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



but, first, of the coefficient of increase peculiar to the partic- 

 ular metal under consideration; second, of the co-efficient of 

 increase dependent upon the co-efficient of the expansion of 

 the metal ; and, third, of a function of a co-efficient express- 

 ing; the resistance of the material at the absolute zero. He 

 finds his formula correctly applicable to the metals plati- 

 num, iron, copper, aluminum, and silver, at temperatures be- 

 tween zero and 350 C. The results of his experiments 

 are given in detail, and afford a valuable basis for still fur- 

 ther investigations. 



In the second part of his memoir he states that, in 1860, 

 when engaged in examining the electrical condition of the 

 Malta and Alexandria telegraph cable, his attention was di- 

 rected toward the fact that the increase in the temperature 

 of the cable could be measured by the increasing resistance 

 to the electrical current ; and accordingly constructed coils 

 of cable wire, of known electrical resistance, inclosed her- 

 metically in iron tubes, out of which passed thick insulated 

 wires; and placing these coils at various points within the 

 mass of the cable, he was able, by examining the varying 

 electrical resistances, to ascertain that the interior of the 

 large mass of coiled cable was steadily rising in tempera- 

 ture, and by pouring cold water thereon saved it from ulti- 

 mate destruction. . Following up this idea, he shortly after- 

 ward constructed thermometer coils, consisting of a spiral or 

 insulated wire, inclosed in a cylindrical silver casing, which 

 he used for measuring ordinary temperatures on land, and 

 which could be used, he suggested, by physiologists and 

 others. The instrument is extremely sensitive, being cor- 

 rect within one tenth of a degree Fahr., or even less; and a 

 modified arrangement of this kind for measuring deep-sea 

 temperatures was presented to the Berlin Academy in 1863. 

 After describing the method adopted by him for determin- 

 ing the temperature of a distant spot, and also a similar ap- 

 paratus furnished by him to the steamship Challenger in her 

 exploring expedition, he gives in detail the method of con- 

 struction of the pyrometer for measuring high temperatures. 

 He states that Professor Bolzain, of Kasan, is at present em- 

 ploying his resistance thermometer for registering the tem- 

 peratures below the surface of the earth, and measuring the 

 temperature of the air above ; and, furthermore, that Mr. Bell, 



