Lessen XL.]' CONCLUDING ADVICE. 305 



Gregory, Ktill, Long, Maskelyne, Vince, and 

 Wales, are writers of distinguished reputation. 

 The best writers on Electricity, are Brooks, Caval- 

 lo, Ferguson, Frank in, Morgan, and Priestley. 

 On Optics, the performances of Harris, Martin, 

 NKWTON, Smith, and Wood, will particularly 

 merit your attention. Various other parts of 

 Philosophy, or Natural Philosophy in general, 

 may be found treated on, either in a popular or 

 scientific way, in the works of Adams, Cavallb* 

 Desaguliers, Emerson, Enfield, Ferguson, Gregory, 

 Keill, Martin, Mariotte, NEWTON, Nicfiolson t 

 Nieuiuentyt, Rowning, Rutherforth, and Ryland. 

 There has also been lately issued into the world, 

 a Dictionary, by my highly esteemed friend, Dr. 

 Charles Hutton, in which abundant information; 

 on astronomical, mathematical, and philosophical 

 subjects may be met with. I would also recom- 

 mend to your notice the periodical publications in 

 which philosophical and mathematical questions 

 are discussed: the principal of these are, the Ladies' 

 Diary and Supplement, Gentleman's Diary, and 

 Mathematical Repository $ besides monthly pro- 

 ductions, several of which are worth notice. Nor 

 tan I here omit pointing out, Maclaurins Piew 

 oj Sir Isaac Newton's Phiosophical Discoveries; 

 and, to those who are acquainted with th<^ French 

 lannuage, the Traitc Elcmentaire de Physique, par 

 M. R. J. Hauy, as works which will amply repay 

 tlie student for any attention he ma\ pay them. 

 And, since the author of a book commonly wishes 



it 



