16 ROYAL SOCIETY OF CANADA. 
or as when rutile crystals are obtained by the action of water vapour 
upon volatile titanium chloride : 
TiC], + 2.0 =-TiO, + 4HCI. 
In other cases crystalline minerals have been produced by the action 
of vapours upon non-volatile bodies. In this way Daubrée obtained spinel 
erystals—heating magnesia and aluminium chloride in vapour of water : 
MgO + 2AICI, + 31,0 = MgAl,O, + 6HOI. 
If again certain chlorides are placed in a flask along with solution 
of sodium carbonate and the air displaced by hydrogen sulphide gas, 
crystals of corresponding sulphides or sulphosalts are gradually produced. 
In this way Doelter obtained pyrargyrite, stephanite, ete. 
Among the most interesting results are those which have been ob- 
tained by heating various bodies in sealed tubes. By this method a num- 
ber of zeolites have been produced, freshly prepared gelatinous silica 
being heated to 150° C. along with aluminium chloride, sodium carbonate 
and calcium carbonate (or CaCl,). By the action of aluminium silicate 
upon potassium silicate, under high pressure and at a temperature of 550°, 
C. Friedel and Sarasin have obtained orthoclase. It has also been found 
that certain minerals after being finely pulverized can be re-crystallised 
by digesting in a sealed tube with carbonated water. In this way Doelter 
obtained crystals of stilbite, after heating for eleven days at 170° C. 
(also natrolite and scolecite at 160° C.). 
Fusion processes have been extensively employed and have yielded 
many interesting results. Simple fusion in some cases renders bodies 
crystalline, as in the case of amorphous antimony sulphide, which is thus 
converted into stibnite. According to Gaudin, also, amorphous alumina 
may be fused in the oxyhydrogen flame and rendered crystalline.’ More 
frequently, however, the addition of some flux such as boric acid or borax 
is necessary. ,Ebelmen, for example, obtained corundum by fusion of 
amorphous alumina in borax, and Bourgeois has prepared calcite by fusing 
calcium carbonate with calcium chloride.” 
A number. of artificial minerals have been produced by fusing 
together their essential constituents—silicates, for example, by fusing 
silica with various oxides or carbonates. In this way have resulted 
augite, leucite, nephelite, anorthite, meionite, ete. The temperature re- 
quired is generally high (1200-1500°C. and over). Some flux is often 
employed, which may or may not take part in the chemical reaction. 
Commonly a metallic chloride (or fluoride) is used, and may supply one 
of the metals required. | 


1 Comp. rend. 1869, Bd. 69, 1342. 
2 Bull. Soc. Min. 1882, Bd. 5, p. 111. 
