Philofophtcal Trauplitons. — TretKife m Time-pieces, ttj 



With fome remarks on the recovery of injured trees. By Thomas Ba? Iter, Efq. 4. Some ad- 

 ditions to a paper read in 1790, on the fubje6t ot a child with a double head. By Everard Home, 

 Efq; F.R.S. 5. Obfervations on the manners, habits, and natural hiftory of the elephant. By 

 John Corfe, Efq. 6. On the decompofition of the acid of borax, or fed, tive fait. By Law- 

 rence de Crell, M.D. F.R.S. Lond. and Edinb. and M.R.I. A. tranflatcd from the German. 

 7. A method of finding the latitude of a place, by means of two altitudes of the fun, and the 

 time elapfed betwixt the obfervations. By the rev. W. Lax, A.M. Lowndes's profeflor of 

 Aftronomy in the univerfity of Cambridge. 8. A fourth catalogue of the comparative bright- 

 ncfs of the ftars. By William Herfchel, LL.D. F.R.S. 9. On a fubmarine foreft on theeaft 

 coaft of England. By Jofeph Correa de Seraa, LL.D. F.R.S. and AS. Appendix. Meteo- 

 rological journal, kept at the apartments of the Royal Society, by order of the prefident and 

 council. 



Traite des Montres a Longitudes, (^c. or a treatife on time-pieces, containing the defcrip- 

 tion, conftrudion, and all the details relative to the workmanfhip of thefe machines ; their di- 

 menfions, the method of trying them, &c. ; together with, i. An inftructive memoir on the 

 fabrication of clocks and time-pieces ; 2. Defcription of two aftronomical clocks ; 3. Trial 

 of a fimple method of preferving the relation of weights and meafures; and of eftabiifhing an 

 univerfal and perpetual meafure. One volume in quarto, with feven engraved plates; by 

 Ferd. Berthoud, of the national inftitute of France, and mechanic to the marine. Sdd at 

 Paris by the author aux Galleries du Louvre, 1792. 



This work *, though it has been printed feven years, has not been publiflied till lately ; and 

 we haften to announce it to the public. It is an important fupplement to the Eflai fur I'Hor- 

 logerie, 2 vols, in quarto, publiflied in 1763 and 1786, and to the Traite des HoHoges marines, 

 1773, of the fame author. 



The firft article confifts of the defcription of a marine time-piece, portable and vertical, de- 

 noted by the number 46, which has been ufed at fea. It is flung in jimbals j and when ufed 

 on fhore it is carried in the pocket. On this occafion we find a defcription of a new free 

 efcapement. 



The fecond chapter prefents a defcription of a portable vertical watch, without a fufpenfion^ 

 diftinguiflied by the number 47. It has the common form of a pocket watch. 



In the third and fourth chapters defcriptions are given of two fmall horizontal watches in- 

 tended to ferve as regulators, remaining at reft in the veflel, carried by their fufpenfions : that 

 which is denoted by number 45 makes four vibrations per fecond. In the other time-piece, 

 no. 48, the balance makes two vibrations per fecond. 



Chapter V. contains the moft effential details for the execution of watches and finall time- 

 pieces for the longitude. 



• Thhi account is given by I-alande in xht Magafin Em-ycbp^tliqor, VII. 1 1 3. 



Chapter 



