484- Intelligence and Miscellaneous Articles. 



an accusation should have been brought against him equivalent to 

 that of robbery, and that stated to have been committed in the last 

 stage of a life devoted to science with so much honour to himself, 

 and benefit to his country and to mankind. 



It may be asked why I did not reply to this last charge at the 

 time it was first made, viz. in 1830, in Mr. Babbage's * Reflections 

 on the Decline of Science in England and on some of its Causes.' 

 I was then abroad on foreign service, and did not return until the 

 lapse of two years. Then Mr. Babbage's book had almost passed 

 into oblivion : moreover, as the Council of the Royal Society were 

 included in the charge, its members (they so many and able) might 

 be considered the proper persons to reply to it ; indeed, even now, 

 my giving it attention is by some friends I have consulted considered 

 unnecessary ; and so I might consider it, did I not know that where- 

 ever pitch is thrown it adheres, and that the renewal of the charge 

 in a book such as Mr. Babbage's is, which may be referred to here- 

 after, if passed over in silence, might be supposed to be founded on 

 truth. 



I am, Gentlemen, 

 Lesketh How, near Ambleside, Your obedient Servant, 



October 20, 1864. John Davy. 



ON THE COMPARISON BETWEEN THE ENGLISH AND METRICAL 

 READINGS IN DOUBLE-SCALE BAROMETERS. 



To the Editors of the Philosophical Magazine and Journal. 

 Gentlemen, 



In the July Number of your Magazine is a paper by my friend 

 Mr. Packe, in which he attributes the larger part of the discrepancy 

 between the barometric pressures corresponding to the French and 

 English boiling-points to the difference between the standard tem- 

 peratures of the French and English units of length. 



I believe this conclusion to be erroneous, and I propose to state, as 

 briefly as possible, my reasons for dissenting from it. 



"First," writes Mr. Packe, " as to the discrepance arising from 

 the standard temperatures. That of the English barometer being 

 30° F. higher than that of the French scale, when the mercurial 

 column is reduced to the freezing-point, the scale of the French 

 barometer is also reduced to the freezing-point, but the scale of the 

 English one is only reduced to the temperature of 62° F. 



" The consequence is that the French barometer, when reduced, will 

 always read higher than the English barometer." 



The unsoundness of this inference will appear from the following 

 considerations. 



By reducing the French barometer we obtain the length of a 

 column of mercury at 0° C, estimated in millimetres, at the standard 

 temperature of 0° C. 



By reducing the English barometer we obtain the length of the 



nected with interests [meaning moneyed interests] I am resolved to live 

 and die at least sans tdche." — See my Memoirs of his Life, vol. ii. p. 176. 



