404 



CATALOGUE.— HEAT, COMMUNICATION. 



of the length is ^L, that of the specific gravity from tem- 

 pering consequently ^ ; but the hammering increases it to 

 Jj. The expansion of water by freezing presents a similar 

 phenomenon. 

 On the flexure of wax and metal in cooling. 



Nich. 8. IV.- 176. 

 Hatchett. Ph. tr. 1803. 118. 



Found that gold debased with impure copper became 

 brittle when cast in moulds of sand, but was rendered 

 ductile when cast in moulds of iron. The specific gravity 

 of standard gold when cast in iron was also greater than 

 when cast in sand, in the ratio of 290 to 289, and in one 

 experiment of 61 to 60. The mefal cooled more rapidly 

 in sand. In some cases the evolution of gas may, perhaps, 

 be concerned in affecting the specific gravity. 



Communication of Heat by contact 

 and in general. 



La Chapelle on a bar of steel becoming 

 hot when withdrawn from boiling water. 

 A. P. II. 25. 



Romberg on the increased heat of the bot- 

 tom of a vessel when removed from the 

 fire. A. P. 1703. H. 24. 



This appears to be a fallacy : with a clean surface it 

 may easily be detected. 



Martine's essay on the heating and cooling 



of bodies. 

 Richmann on the laws of the decrement of 



heat. N. C.Petr. I. 174. II. 172. 



Makes its decrement as the surface exposed and as the 

 difference of temperature conjointly. 



Richmann on the cooUng bodies in air. 



N. C. IV. 241. 



Insists that a ball of metal 4 inches in diameter cannot 

 be heated by boiling water beyond 207° : and the ex- 

 periments seem to indicate, that even in cooling its tem- 

 perature is always lower, which indeed is the only point 

 that can affect the theory. Brass and copper retain heat 

 longer than iron, iron than tin, and tin than lead. 



Lambert on heating and cooling. Act. Helv. 



II. 172. 

 Lambert Pyrometrie. 

 Darwin. Ph. tr. 1757. 240. 



Supposes steam to float in air, and retain its heat. 



Musschenbroek's table of the time of heatina: 



of different bodies. Introd. II. 678. 

 Euler on the motions of fluids from heat. 



N. C. Petr. XI. 232. XIII. 305. XIV. 



270. XV. 1, 219. 

 Braun on the communication of heat. N. C. 



Petr. XII. 289. Roz. I, l. 



Confirms Richmann's experiments on boiling water and 

 alcohol : but finds the result different with wine and oils. 

 For these, however, the boiling point must be variable, 

 and the result is of no value. 



Roy. Ph. tr. 1777. 720. 



Observes, that water is a very bad conductor of heat. 



Erxleben on the laws of heat. N. C. Gott. 

 1777. VIII. 74. 



Exceptions to the law of Newton, Richmann, and 

 Lambert. 



Achard on the conducting powers of gases. 



A. Eerl. 1783. 84. 

 Achard's comparison of heat and electricity. 



Roz. XXII. 245. 

 Achard on the cooling of bodies in air of 



different densities. A. Berl. 1785. 24. 



Makes no general conclusions. The difference betvvee* 

 the rates of cooling in air exhausted to | and to \ was some- 

 times imperceptible, and scarcely in any case jL. 



Fordyce's experiment on heat. Ph. tr. 1787. 

 310. 



Two equal cylinders of pasteboard were inclosed in 

 eider down under glass, one was covered with iron, 

 the other with pasteboard, both painted with the same 

 black paint, which was exposed to the sun's rays : th« 

 pasteboard never transmitted a heat of more than nop 

 the iron 121°: the iron also retained its heat much the 

 longest. 



Sir B. Thompson on heat. Ph. tr. 1786. 273. 

 Ess. II. viii. Repert. IV. 30. Gilb. V. 



288. 



The conducting power of mercury being 1 000, that of 

 moist air was 230, of water 313, of common air 80.41, 

 of air \ as dense 80.23, of air ^ as dense 78, of a 

 vacuum 55. The two last numbers, compared with the 

 conducting power of common air, appear to indicate a 

 formula of this kind, 55-J-25.4(fJT, d being the density, 

 compared with that of the atmosphere. 



