320 Intelligence and Miscellaneous Articles. 



platinum a wire spiral of the same metal was dipped ; and at the 

 instant when the surface began to solidify, a rosette of solid pla- 

 tinum was taken up with the wire and immersed in the water of 

 the calorimeter. With five rosettes, weighing respectively 57*3, 

 57*87, 81-5, 40*67, and 49 grammes, the following heatings of the 

 water of the calorimeter for 1 gramme of platinum were suc- 

 cessively observed— 0°-0722, 0°*0704, 0°*0702, 0°*0715, and 

 0°'070S ; mean, 0°*0710. The mass in water of the calorimeter 

 being 1052-524 grammes, we have 



2 = 74*73 units 



for the quantity of heat given up by 1 gramme of platinum from 

 the fusion-point to 15°, the mean temperature of the calorimetric 

 liquid in these experiments. 



If it be admitted that the specific heat of platinum is repre- 

 sented, up to the fusion-point, by the formula above-given, it 

 follows that, for the fusion-temperature of platinum, 



T=1779°. 



But the increase of the specific heat of platinum with the tempe- 

 rature is without doubt accelerated in the vicinity of the f using- 

 point, the platinum passing through the pasty condition before 

 becoming liquid ; the true temperature of fusion will therefore be 

 slightly below the number thus obtained. 



III. By running a certain weight of melted platinum taken as 

 near as possible to the fusion-point, into the platinum eprouvette 

 of the calorimeter, we can measure the total heat of fusion of the 

 metal — that is to say, the quantity of heat necessary to transform 

 ] gramme of platinum at zero into liquid platinum at the very tem- 

 perature of fusion. With weights of 47*51, 78*3, 40*82, and 

 158*79 grammes of melted platinum, the following heatings of the 

 water of the calorimeter, for 1 gramme of platinum, were suc- 

 cessively observed— 0°*0756, 0°*0757, 0°*0747, and 0°*0767; mean, 

 0°*0757. The mass in water of the calorimeter being, in these ex- 

 periments, 1345*42 grammes, we have for the total heat of fusion 

 of platinum, starting from 170° (the mean temperature of the water 

 of the calorimeter), 



L= 101*85 units. 



If from this we deduct the quantity of the heat q necessary to 

 raise 1 gramme of platinum to the melting-temperature, we have 

 the latent heat of fusion 



X = 27*18 units. 



IV. The melting-point of silver, determined in the course of 

 these researches, upon a pure example kindly prepared for me by 

 M. Lory, was found to be 954°, a temperature very near to that 

 given by M. Edraond Becquerel. Other melting-points (those of 

 gold, copper, &c.) shall shortly be measured. — Comjptcs llendus de 

 VAcademie des Sciences, Sept. 10, 1877, tome Ixxxv. pp. 543-546. 



