186 



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



A commercial casting gave 0-0835 (3), 0-0835 (5). Mass approxi- 

 mately 106J grammes. Mr. Kace found 99'5 per cent, zinc, a small 

 quantity of tin, traces of arsenic, copper, lead, aluminium. 



Silver. 



A specimen of bar silver, supplied by Elkington and Co., was found 

 by Mr. Francis Jones to contain silver 98*06 per cent., gold 0'17 

 per cent., the balance being at least partly copper. It gave '051 33 (5) y 

 0-05147 (5), 0*05129 (5), mean say 0-0514. Mass approximately 176 

 grammes, calorimeter C, fall of temperature approximately 4 -5. 



Tin. 



A specimen supplied by Johnson, Matthey and Co., practically pure, 

 gave 0-04993 (3), 0-04973 (4), 0-04963 (5), mean say 0-0498. Mass 

 approximately 173 grammes, calorimeter E, fall of temperature 

 approximately 2-4. An additional experiment, calorimeter C, gave 

 0-04997 (5). 



A commercial specimen gave 0*0502 (3), 0'0503 (3), 0*05001 (5), 

 0-04997 (5). Mass approximately 130 grammes. In this case the 

 casting contained numerous small air-holes, and was only roughly 

 trimmed in the lathe. A considerable amount of liquid air was carried 

 into the calorimeter, and this probably makes the results a little too- 

 high. Mr. Eace found tin 99'3 per cent., lead 0'45 per cent., traces of 

 iron and zinc. 



Summary. 



In Table IV are collected the results already given. For comparison 

 Behn's numbers are added in the last column. 



Table IY. 





