502 Professoi' W. C. Boherts- Austen [Feb. 5, 



WEEKLY EVENING MEETING, 

 Friday, February 5, 1892. 



Sir Frederick Abel, K.O.B. D.C.L. F,K.S. Vice-President, in the 



Chair. 



Professor W. C. Eoberts-Austen, C.B. F.E.S. MM.I. 



Metals at High Temperatures. 



I propose this evening to consider, first, the methods of measuring 

 high temperatures, and, second, to describe certain effects they pro- 

 duce on metals. 



Geber, writing in the eighth century, gives directions for obtain- 

 ing high temperatures, but points to the difficulties that arise in 

 practice, " because fire is not a thing which can be measured, ' sed 

 qiioniam non est res ignis, quse mensurari possit.' " * It is not sufficient 

 to attain temperatures that are not known to be high ; it is necessary, 

 for the purpose of modern investigation, to measui'e them with 

 accuracy ; and few of the early chemists in this country did more in 

 affording a basis for the study of metals at high temperatures than 

 Robert Boyle, the application of whose well-known law to solutions 

 of metals in each other has been made evident by recent work. The 

 30th December last was the third centenary of his death ; it is well, 

 therefore, that this lecture should begin with a tribute to his 

 memory. He suggested improvements in the ordinary mercurial 

 thermometer, f constructed what would appear to be the first air 

 thermometer with an index ; and although he did not do much for 

 thermometry at high temperatures, he appears to have been struck by 

 what must have been a quaint device for regulating high temper- 

 atures, for he points out that " the great mechanic, Cornelius Drebel J 

 made an automatous musical instrument and a furnace which he 

 could regulate to any degree of heat by means of the same instru- 

 ment." He indicates various degrees of intensity of heat by 

 reference to the colour of a glowing mass of fuel, and says that, § 

 " tho' we vulgarly say in English, ' a thing is red hot,' to express a 

 superlative degree of heat, yet, at the forges and furnaces of artificers, 

 by a white heat they imderstand a further degree of ignition than by 

 a red one." It is not a little strange that for three centuries after 

 his death the same vague expressions have constantly been used in 

 describing high temperatures. 



* From the edition of his * Summa Perfectionis Magisterii,' p. 28, published 

 in Venice, 1542. 



t Boyle's Works, Shaw's edition, vol. i. p. 575, 1738. 



X Cornelius van Drebel, 1572-1634, Boyle, loc. cit. vol. iii. p. 38, 1738. 



§ Loc. cit. vol. ii. p. 28. 



