ii CONTENT S. 



VIII, Account of tlic original Invention of the circular Inilrument for per- 

 forming Calculations on the Principles of Gunter's Rule made by Clairault 

 le Pere, and commuicated to the Royal Academy of Sciences in the Year 

 1727. (W. N.) - - - - - - p. 40 



MAY 1801. 



Engravings of .the following Objefts: 1. A Galvanic Apparatus. 2. Figure 

 exhibiting the Difperfion of Heat and Light by the Prirni, as difcovercd by 

 Dr. Herfchel ; and, 3. Dr. Young's Elucidations of the Phenomena of Sound. 



I. Obfervations and Experiments on the Galvanic Power. By a Correfpondent. 



p. 41 



Opinion that Galvanifm is a diftiniS power from electricity — curious efFefl on refin — other effeds — 

 different effo£l of the (liock according to age. Combination of plumbago and zinc, in a (gal- 

 vanic range : other experiments and remarks to ftiew tiiat Galvanifm is not eleclricity. 



II. Third Communication on the Trains of "Watches. By the Rev. W. Pearfon. 



p. 46 



III. A Method of meafuring a Ship's Way at Sea, with Obfervations on other 

 ' Branches of the Art of Navigation. By John Cooke, Efq. M.R.I A. Com- 

 municated bv the Author. - - - - - . 48 



Tlie aperture of an horizontal tube being directed againft the relative fiream produced by a fhip's 

 motion, the water of tlie fca is forced in, and being condu6led upwards, to the level of the. 

 external furface, the quantity dilcharged in a receptacle within the ihip, which is propor- 

 tional to the fpace parted over, wliatever may be the variations of velocity. 



IV. On the Efcapemcnt of Time Pieces. By Mr. Thomas Reid. p. 55 



Obfervations and fa6ls relative to the conftrufllon and hiftory of various efcaperaents. 



V. Enquiries relative to the Laws of Affinity. By Citizen Berthollet, Member 

 of the National Inftitute of Arts and Sciences. (Concluded from page 21.) 



p. 58 



VI. Experiments on tlic Solar and on the Terreflrial Rays that occafion Heat j 

 with a comparative View of the Laws to which Light and Heat, or rather 

 the Rays which occafion them are fubjeft, in order to determine whether thej 

 are the fame or diflferent. By William Herfchel, LL.D. F.R.S. p. 69 



Exliibitions of the fpaces and intenfities through which the rays of heat and light arc fpread by the 

 prilin. They are as 5 to 3. — The fines of refraftion of heat are proportional to the fines of in- 

 .t-idence. The achromatic prifm corredls the aberration of heat. Focus oi heat does not 

 coirxidc with that of light. 



VII. Out- 



