the DiJJblution of Metals in Acids. 36^ 
of nitre ; nor by another mixture in the proportion of 200 
grain-meafures of oil of vitriol to 150 grains of nitre, and 
confequently no gas was produced in either inftance. 
12. With a mixture in the proportion of 200 grain-meafures 
of oil of vitriol and 100 grains of nitre, the tin began foon to 
beaded on, and to be diffbfed through the liquor; but no 
extrication of gas appeared until the digeftion had been con- 
tinued two hours in boiling water ; and then it took place, and 
gave a frothy appearance to the mixture, which was of an 
opaque white colour, from the powder of tin diffufed among 
it. In this experiment the quantity of tin thus calcined was. 
73 grains, and the quantity of nitrous gas extricated during 
this adion on the tin was 8500 grain-meafures. Then, upon 
pouring 200 grains of water into the retort, a frefh efferves- 
cence took place between the water and the white opaque mafs, 
and 4600 grain-meafures of nitrous gas were thrown into the 
inverted receiver. 
13. With a mixture in the proportion of 100 grain-meafures 
of oil of vitriol to 30 grains of nitre, 30 grains of tin were 
diffolved or calcined, and the nitrous gas, which began to be 
extricated much fooner than in the laft mentioned experiment 
with a larger proportion of nitre, amounted to 6300 grain- 
meafures. Water, added to this folution of tin, did not pro- 
duce any effervefcence. 
14. With a mixture in the proportion of 200 grain-meafures 
of oil of vitriol, 200 grains of nitre, and 200 grains of water, 
1 33 g r ains of tin were aded on with an effervefcence, which 
took place violently,, and produced 6500 grain-meafures of 
nitrous gas. 
15. The feveral mixtures above mentioned* in different pro- 
portions of nitre and oil of vitriol, did, by the help of the 
heat 
