Manchester Memoirs, Vol. xlviii. (1904), No. 0. 7 



It will be observed that the differences between the 

 experimental and calculated values of the specific heats of 

 the aluminium-copper and aluminium-zinc alloys are small 

 and within the limits of experimental error.* As regards 

 the specific volumes, the experimental values are in 

 moderate agreement with the calculated. In the case 

 of the aluminium-zinc alloys we should expect the mean 

 specific volume of a complete casting to be nearly 

 normal from the evidence of the fusibility-curves and 

 microscopic examination, for these alloys, according to the 

 classification of Le Chatelier,-f- belong to the same group as 

 tin-bismuth, lead-antimony and lead-tin, all of which have 

 normal or nearly normal specific volumes.^ On the other 

 hand, aluminium and copper give an abnormal fusibility 

 curve,§ and, according to Guillet,|| form compounds 

 (CU3AI, Cu Al and CuAK) of markedly abnormal densities.il 



*For aluminium-copper compare a determination by Longuinine {Ann. 

 de Chim. et de Phys.^ 1882, Vol. 27, p. 407) of the specific heat of Al il*3, 

 Cu 88-7. Longuinine's values are '10432 (found), 'loSg (calculated). The 

 difference here seems larger than the experimental error, and it is worth 

 noting that the composition is nearly that of CugAl. In a recent memoir 

 (again quoted in a subsequent note) Longuinine and Schukareff give the 

 following values: "1586 for CuAlg (approximately 44 per cent. Cu), "1502 

 for CU4AI9 (approximately 51 per cent. Cu). The calculated values (using 

 the numbers for Al and Cu given in the present paper) are respectively "164 

 and "iSSi so that here also the observed are appreciably lower than the 

 calculated values. 



AMetallographist, 1898, Vol. i, p. 95 (Charpy). 



JMaey, loc. cit. 



§Le Verrier quoted by Roberts- Austen, Metallographist, 1898, Vol. i, 

 p. 346; Le Chatelier, Annales des Mines, 1897, Vol. 11, p. 201. 



\^Science Abstracts, 1903, No. 584. 



IT Compare Longuinine and Schukareff on the heats of formation of 

 aluminium-zinc and aluminium-copper alloys, Archives des Sciences, 1902, 

 Vol. 13, pp. 5-29, and 1903, Vol. 15, pp. 49-77. In the second of these 

 memoirs the authors give the specific heats of Cu 44 per cent, and Cu 

 51 per cent, quoted in a previous note, and also values for the densities 

 of these two alloys. The value for the density of Cu 44 per cent, shows a 

 considerable contraction (about 6 per cent.), that for the density of Cu 

 51 per cent, no alteration of volume. 



