472 Royal Society : — Prof. Matthiessen on the 



I liave taken the liberty of writing in the above -j-j -j- f° r 



S x , 8 1J} and P for 8 in the original. It will be useful to bear in 

 mind that in any operator such as E^ or E 2 *, the asterisk forms 

 an integral part of the symbol j*. Thus E^Eg*, if we choose, 

 may be written under the form of E A * multiplied by E 2 #, i. e. 

 (Ej*) X (E 2 *), where the cross is the sign of ordinary algebraical 

 multiplication, 



LXIV. Proceedings of Learned Societies. 



ROYAL SOCIETY. 

 [Continued from p. 393.] 



June 21, 1866. — Lieutenant-General Sabine, President, in the 



Chair. 



HPHE following communication was read : — 

 •*- "On the Expansion by Heat of Metals and Alloys/' By A. 

 Matthiessen, F.R.S. 



In a paper "On the Expansion by Heat of Water and Mercury "J, 

 a method of determining the expansion of bodies is described, by 

 which good results can be obtained with comparatively small quan- 

 tities of the substances to be experimented with. This method, that 

 of weighing the body in water at different temperatures, has been 

 employed for the present research. The results obtained are given 

 in the following Tables : — 



+ The operant, sign of operation, and operand form a triad somewhat 

 analogous to the subject, copula, and predicate of the logicians; and as 

 in the admirable new school of philosophical grammar the copula is for 

 certain purposes incorporated with the predicate, so ex converso in this 

 system the sign of operation is taken up by the operant ; but, herein 

 advantageously differing from the practice of the grammarians alluded to, 

 the combination assumes a distinct name from its leading element and is 

 styled an operator. 



I ought to mention that my information in this matter is derived from the 

 statements which have appeared in the public prints, and not from a direct 

 study of that wonderful manual of the quintescence of grammar so unpre- 

 tendingly ushered into the world as a primer, but which, whatever name 

 it goes by, can hardly fail to bring about a philosophical revival of the 

 intellect of the rising generation of Englishmen. I wait for a favourable 

 opportunity of leisure to address the full energies of my mind to the invi- 

 gorating and congenial task of mastering its subtle differentiations and 

 profound and arduous abstractions. 



t Phil. Trans. 1866, part 1. 



