eATALOGUE. — HEAT, PERMANENT EFFECTS, 



*m 



Formula. Dalton. 

 808° 150.9 (114. is) 



303 153.4 



304 155. S 



305 158.S 

 308 160.9 



307 163.5 



308 166.0 

 30y 168.7 



310 1/1.4 



311 174.1 



312 176.2 



The vapour of sulfuric acid ousht to have a force of .1 

 at 390", that of mercury at 460", the one boiling at 590", 

 the other at 660" Dalton. 



Chemical and Physiological Efects. 



See Economy of Heat. 



Richinann on solutions at different tempera- 

 tures. N. C. Petr. IV. 270. 



Blagden's observations made in a heated 

 room. Ph.tr. 1773. 111. 



Supported a heat of about 300" in air ; and there was no 

 evaporation from the skin to assist in cooling, on the con- 

 trary, water was deposited. TiUet found two girls that 

 supported a heat of 2Soa in an oven. Mercury could 

 not be borne at 120", nor water at 125"; oil was sup- 

 portable at 129", and spirits of wine at 130". 



Harniss on the chemical action of light and 



heat. Nich. V. 245. 

 Journ. de phys. LVII. 66. 



An account of a Spaniard who washed his hands and 

 face in oil at 224", put his foot on a red hot iron, and 

 held a lighted candle to his leg. His pulse was 130" 

 or 140". 



See Physiology. 



Soda and potash are said to exchange their acids at dif- 

 ferent temperatures. 



In general a bath is pleasantly warm from 90" to 1 1 0° ; 

 we drink tea about 11 5 " or more, coffee sometimes at 130» 



Permanent Effects of Heat and 

 Cold. 



*Hooke on glass drops. Micrographia. 

 Homberg on the Batavian drops. A. P. II. 



85. X. 146. 

 Wolf on brittle bottles. A. P. 1743. H. 43. 

 Brur.ion the Bologna bottles. Ph. tr. 1745. 



XLIII. 272. 



Watson on unannealed glass vessels. Ph. Ir. 



1745. XLIII. 505. 

 Casali on unannealed glass. C. Bon. II. 



i. 321,328. III. 40G. V. ii. I69. 

 Lecat on glass drops, and on the tempering 



of steel. Ph. tr. 1749. XLVI. 175. 

 Observes, that a drop may sometimes be ground away 

 by emery and oil without breaking. Compares tempering 

 to annealing. 



Hanovv on the Bologna jars. Danz. Gesell. 



I. 584. III. 328. 

 Hawoz» Veisuchemit den Springkolbchen. 4. 



Danz. 1751. 

 Bosc d'Antic on glass drops. S. E. IV. 

 Kaestner de lacrymis vitreis. Dissert, viii. 



59. 125. 

 Maupetit on the glass drop. lloz. VI. 394. 

 *Coulomb. A. P. 1764. 'ZQ5. 



Found that the force of tonion is equally powerful in 

 wires annealed and unannealed: they perforaed their vibra- 

 tions in equal times. A tempered bar required also as 

 much force to deflect it to a given angle, as a hard one 

 of the same dimensions. A soft bar, a spring tempered, 

 and a hard one, were bent to equal angles by 5 pounds ; 

 with 6 the hard bar broke, with 7 the soft one bent, but 

 returned as far from its new position upon the removal 

 of the weight, as if it had not bent. The elastic bar 

 was broken by 18 pounds. Chladni also found the sound 

 of soft iron and steel similar to that of the hardest, and I 

 have observed the same in a tuning fork. This may be 

 inferred from the theory of annealing ; the whole cohesive 

 force not being affected by the partial extensions of some 

 strata and the consequent condensation of others, 



Nicholson. Manch. M. II. 370. 



Observes, that the specific gravitj' of lead and tin varies 

 in the third figure of the number expressing it, accord- 

 ing to the different modes of cooling. 



Guyton on tempering steel. Ann. .Ch. 

 XXVII. 186. 

 From Nicholson. See Cutlery. 



Cavallo. Nat. Ph. II. 27- 



A piece of steel, whicli measured 2.769 inches when 

 soft, was found, by Mr. Pennington, to measure after 

 hardening, 2.7785, and when again tempered so as to 

 become blue, 2.768. The specific gravity of hammered 

 steel is 7.84, that of hardened steel 7.816. The difference 



