Frozen powder is unfit for use. It will burn or smoulder, and some of it may be left in the drill hole to explode when it is not wanted to.

CHAPTER XI.
ATOMIC WEIGHTS.

The atomic weight of a mineral is the proportion in which its elements are united, i.e., they represent the weights of the different atoms in the minerals. Hydrogen, being lightest, is made the unit.

Supposing it becomes desirable to find the proportional weights of the elements of any substance with a known chemical formula. Multiply the atomic weight of each element by the number of atoms of such element, and add these products together; this will give the weight of all. The proportion of each is arrived at by a simple calculation.

For instance: How much metallic silver is there in 100 pounds of Argentite, or silver glance, whose composition is Ag2S?

Then

Ag equals 108 times 2,—216.
S equals 32 times 1,—32.

So that in every 248 pounds of the glance there are 216 pounds of metallic silver, and by proportion we find its percentage is 87.1.

The following tables give the symbols, atomic weights and specific gravities of certain abundant elements. Rare elements are omitted:

Symbol.At. Wt.Sp. Gr.
AluminumAl27.52.56
AntimonySb122.06.70
ArsenicAs755.70
BariumBa1374.00
BismuthBi2109.7
CalciumCa401.58
CarbonC123.50
ChromiumCr52.56.81
CobaltCo58.87.70
CopperCu63.58.96
Gold (Aurum)Au196.7719.30
HydrogenH1.00.069
IodineI127.04.94
Iron (Ferrum)Fe56.07.79
Lead (Plumbum)Pb207.011.44
ManganeseMn55.08.1
Mercury (Hydrargyrum)Hg20013.59
NickelNi58.88.60
NitrogenN14.00.972
OxygenO16.01.105
PhosphorusP31.01.83
PlatinumPt197.421.53
Potassium (Kalium)K39.00.865
SeleniumSe79.54.78
SiliconSi28.02.49
Silver (Argentum)Ag108.010.05
Sodium (Natrium)Na23.00.972
SulphurS32.02.05
TelluriumTe129.06.02
Tin (Stannum)Sn118.07.28
ZincZn65.07.14