184 



Mr. H. E. Schmitz, On the Determination of [Feb. 2, 



Lead. 



A specimen supplied by Johnson, Matthey and Co., of a purity of 

 about 99-9 per cent., gave 0-02942 (3), 0-02933 (4), 0-02936 (5), 0*02924 

 (7), mean of the first three 0*0294. Mass of lead approximately 250 

 grammes, calorimeter C, fall of temperature approximately 3 '6. 



Table III gives the results of ten experiments on commercial sheet 

 lead. The object of these experiments was to test the comparability 

 of the results when the mass and also the proportion of surface to 

 mass was varied. The shapes of the specimens are given in Table VI. 

 All the calorimeters made use of in the investigation were included in 

 this series of experiments, with the secondary object of testing the 

 comparability of results obtained with different calorimeters. 



Table III. 



Five further experiments with the piece of lead of mass 285-8 

 grammes, using calorimeter C, gave 0-0295 (3), 0'0296 (3), 0*02945 (3), 

 0-0295 (4), 0-02945 (5). Mean result for sheet lead 0*02935. An 

 analysis by Mr. Eace showed lead 99*5 per cent., tin 0' 13 per cent., 

 traces of iron, copper and antimony. 



Aluminium. 



A specimen supplied by Johnson, Matthey and Co., was analysed by 

 Mr. Eace and found to contain 98 per cent, of aluminium, 1 per cent, 

 of zinc, 0-7 per cent, of iron, small quantities of silica, etc. It gave in 

 the first instance in two experiments 0-1725 (4), 0*1733 (5), For these 

 experiments the piece of metal had been only roughly trimmed in the 

 lathe. As a comparatively large quantity of liquid air was evidently, 

 in these two experiments, carried into the calorimeter, the piece of 

 metal was reshaped with a very smooth surface. It now gave 0-1731 (3), 

 0-1721 (4), 0*1721 (5), mean 0*1724. Mass of aluminium approximately 



