THE SCIENTIFIC SPIRIT IN ENGLAND. 



265 



the part of some of the great laboratories of Paris or of 

 Germany, in turning out a large number of well-trained 

 experimentalists. Davy may be said to have educated 

 Faraday, though he was suspected of having become 

 jealous of him, and Faraday declared he received only 

 one valuable suggestion from any member of his audience 

 during the whole course of his lecturing. It is the 

 strongly marked individuality of all these great men, 

 expressed in their persons, their lives, and their works, 

 rather than the character of the institution itself, which 

 has given celebrity and historical importance to the Eoyal 

 Institution. John Dalton's l position in the Literary and 32. 



Manchester 



Philosophical Society of Manchester was similar to that Literary and 



Philosophi- 



of Davy and Faraday in the Eoyal Institution; and as cai society. 

 Faraday can in some sense be called a pupil of Davy, so 

 can Prescott Joule 2 be termed a pupil of Daltou, whom 



1 See note, p. 245. 



2 James Prescott Joule (1818- 

 89), a native of Salford, "received 

 from Dalton his first inducement 

 to undertake the work of an ori- 

 ginal scientific investigator." He 

 was one of the first who tried to 

 measure electrical action in terms of 

 the units of well-known mechanical 

 or chemical changes. His publica- 

 tions began in 1 840. Weber's ' Elec- 

 trodynamische Maasbestimmungen , ' 

 that great monument of exact meas- 

 urement, was published in 1846. 

 Mayer's first publication, contain- 

 ing a calculation of the mechanical 

 equivalent of heat, bears the date 

 1842. But the great publication of 

 Gauss, in which he measures mag- 

 netic action in ordinary mechanical 

 (or absolute) units, dates from 1832 : 

 ' Intensitas vis magneticse terrestris 

 ad mensuram abnolutam revocata' 

 (Comm. Societ., Getting., 1832, &c.) 



Joule in 1843 published the first 

 of his accurate determinations of 

 what is termed in physical science 

 " J " or " Joule's equivalent of 

 heat." He read successively papers 

 on this subject before the meetings 

 of the British Association, first at 

 Cork (1843), giving the constant 

 " J " as 838, then as 770, then as 890 

 in 1845 (Brit. Assoc. at Cambridge), 

 lastly at Oxford (1847) as 781'5. 

 From this meeting dates the ac- 

 quaintance and scientific co-opera- 

 tion of Joule and Thomson (Lord 

 Kelvin) and the gradual recognition 

 of the importance of the subject 

 by other men of science (see Thom- 

 son's address on Joule, 1893, in 

 ' Popular Lectures and Addresses,' 

 vol. ii. p. 558 sqq.) Helmholtz's 

 memoir, " Ueber die Erhaltung der 

 Kraft," which was theoretical as 

 Joule's were experimental dates 

 also from 1847. 



