Notices respectiiig Ne'w Books. 459 



mate times given in the problem only for the purpose of finding 

 the interval. 



In my remarks on Mr. Burns's letter I stated that " Mr. 

 Burns altogether misapprehends the nature of the problem; 

 for he assumes as known, not only the interval of time between 

 the observations, but the true appai-ent time of each observa- 

 tion." 1 noted the mistake in his assumption in italics. Mr. 

 Burns, however, in referring to this remark, prints it the "ap- 

 parent time and the interval; " and other observations in his 

 reply show that the typographical transposition was not acci- 

 dental. 



Having before shown that Mr. Burns had failed in giving 

 any solution to the double altitude problem, and having now 

 shown that he has not rightly stated the cause of his mistake, 

 I take my leave of the subject, as the peculiar method of trial 

 and error now proposed by Mr. Burns for the solution of this 

 problem is in no danger whatever of being adopted. Mr. Burns 

 is right in remarking that " no name however great can sanc- 

 tion error," and he is fully entitled to all the consolation that 

 can be derived from the consideration that even Newton made 

 a mistake. I am, sir, your obedient servant, 



Greenwich Hospital, 17th Dec. 1825. Edward RiDDLE. 



LXIX. Notices respecting New Books. 



T^HE Second Part of the Philosophical Transactions for 

 -*• 1825 has just appeared, and the followhig are its con- 

 tents : 



On the anatomy of the mole-cricket. By J. Kidd, M.D. 

 and F.R.S. Reg. Prof, of Medicine in the University of Ox- 

 ford*. — Further observations on planariag. By J. R. John- 

 son, M.D. F.R.S. — On the influence of nerves and ganglions 

 in producing animal heat. By Sir Everard Home, Bart. 

 V.P.R.S. presented by the Society for the Improvement of 

 Animal Chemistry. — An essay on Egyptian mummies ; with 

 observations on the art of embalming among the ancient 

 Egyptians. By A. B. Granville, M.D. F.R.S.— On the tem- 

 porary magnetic effect induced in iron bodies by rotation. 

 By P. Barlow, Esq. F.R.S. — Further researches on the pre- 

 servation of metals by electro-chemical means. By Sir Hum- 

 phry Davy, Bart. Pres. R.S. — On the magnetism of iron 

 arising from its rotation. By Samuel Hunter Christie, Esq, 

 M.A. — Some account of the transit instrument made by Mr. 



• Sec our present Number, p. 401. 



3 M 2 Dollond, 



