MINERALS AND GEOLOGY OF CANADA. 19 
The Water-test.—Many solid minerals contain a considerable 
amount of water, or the elements of water, in some unknown physical 
condition. Gypsum, for example, contains 20.93 per cent. of water. 
In order to ascertain if a substance yield water, we chip off a frag- 
ment (of about the size of a small pea) and heat this in a common 
test-tube (or better, in a small “ bulb-tube ” or glass tube closed and 
expanded at one end, as shown in 
the accompanying figure) over the 
flame of a little spirit lamp. If 
water be present, it will rise and 
condense in the form of a thin film 
or in small drops, on the cold neck 
or upper part of the tube. When 
the moisture begins to appear, the 
tube must be held in a more or less 
horizontal position, otherwise a 
fracture may be occasioned by the 
ili water flowing down and coming in 
Fig. 22. contact with the hot glass. A small 
spirit lamp may be made by fitting a piece of glass tubing an inch 
long (to serve as a wick holder) into the cork of any short, stout 
bottle. A proper lamp, however, with a glass cap to prevent the 
evaporation of the spirit when the lamp is not in use, can be pur- 
chased for a quarter of a dollar. 
This concludes our review of the more common characters pos- 
sessed or exhibited by mineral bodies. The application of these 
characters to the actual determination of Canadian minerals, by 
means of an original Tabular Distribution or Arrangement, will be 
shewn in the next number of the Journal. 
ERRATA. 
Figure 7 (on page 7) has been accidentally printed in a reversed position. 
Page 5, line 17, for “ realgar, or sulphide of arsenic,” read “‘realgar, a sulphide 
of arsenic.” 
Page 15, line 5 from bottom, for “which,” read “ whilst this.” 
