xv KNIGHT'S MAGNETICAL MACHINE 215 



at his death left him his executor. Fothergill presented 

 the magnetic machine to the Royal Society, with a paper 

 descriptive of it, which was read in 1776. The apparatus 

 is still in existence, although it has lost much of its strength : 

 it was used by Faraday in 1831 for his researches on 

 induction currents. 1 



In departments of knowledge which he himself had 

 no time to cultivate, Fothergill had the insight to perceive 

 where advance was being made, and the ready will to 

 help it forward. His friend Joseph Priestley, whose 

 liberal views in theology and politics, as well as in science, 

 made him famous but kept him poor, was carrying 

 out those experiments which revealed the secret of 

 the atmosphere. Fothergill proposed to find him 100 

 every year to enable him to continue and enlarge them. 

 Priestley declined so large a sum, but accepted 40, 

 which his friend regularly sent him, having induced that 

 upright and generous whig statesman Sir George Savile, 

 and two others, to join him in providing it. After some 

 years, when Lord Shelburne's bounty to Priestley was 

 reduced, Fothergill arranged that he should receive a 

 much larger annual subsidy, Drs. Watson (father and 

 son), Josiah Wedgwood and several others, taking, to 

 their honour, a share in this duty ; not to mention Dr. 

 Heberden and the generous Mrs. Rayner. " Without 

 this assistance," Priestley wrote to Franklin, " I must 

 have desisted altogether." Fothergill continued the aid 

 until his death, when Samuel Galton took his place. 

 Such were Fothergill 's benefits, hidden from the public 

 eye, so that of many of them no record has come down 

 to us. 2 



1 The Magnetic Machine is now in the Science Museum, South Kensington. 

 See Phil. Trans. Ixvi. 591 ; MS. Letters and Papers, Dec. vi. 64, Roy. Soc.; 

 Foth., Works, i. 411; and information kindly furnished by the late Prof. 

 Silvanus P. Thompson. 



2 Memoirs of Dr. J. Priestley by himself, ed. 1904, p. 58 ; Letter, Priestley 

 to Franklin, 1779, in Sparks, Franklin, vi. 423 ; Diet. Nat. Biog. When ill in 

 1780 Priestley was attended by Fothergill, Webb, 'Heberden and Pringle. 

 Ford, List of Franklin Papers, No. 593. Fothergill essayed in 1744 to make 

 some analysis of the moisture contained in the atmosphere. Later he gave 

 some thought to Rain, noting that the raindrops increased in size and velocity 

 as they fell, and surmising that they attracted the moisture of the air through 

 which they passed. It is now known, however, that rain often passes through 



