BY MOLECULAR COALESCENCE. "i 
the spherical form of the latter being particularly perfect 
and beautiful. But muriate of magnesia, when decom- 
posed in the same manner, and under precisely the same 
conditions, does not furnish globules, but crystals of car- 
bonate of magnesia, evincing no tendency to become 
globular. 
After the slides have been withdrawn from the bottle, 
all the globules deposited on their upper surface may be 
rubbed off with the finger, or, if very closely adherent, 
washed off with muriatic acid, care being taken that it 
does not touch the edge of the slide, and so reach the 
opposite surface. Afterwards, the lower surface, which 
has the clearest and most perfect globules upon it, must 
be well washed for several minutes, or half an hour, by a 
stream of water running from a tap, so that all the gum 
may be removed. It will then be necessary to wash it 
well in distilled water, in order that no deposit from the 
impure water may be left on the glass when it is dried. 
The specimen, especially if it is to be put up in Canada 
balsam, should now be further dried, on a plate placed 
over boiling water, and afterwards washed with oil of 
turpentine. In mounting these calculi in Canada balsam, 
the balsam must not be boiled on the same slide as the 
calculi, as, in this case, the heat employed being too 
intense, would cause the calculi, containing triple phos- 
phate in combination with the carbonate, to become filled 
with rhomboidal crystals; but the balsam, mspissated on 
another slide, may be poured hot upon the one having on 
it the globules. Lastly, a thin glass cover of the width 
of the slide may be placed upon it, resting at each end 
upon a ledge of thin glass. The deposit which remains in 
the bottle may be next examined, and put up in any way 
that may be thought proper. The large ‘caleuli contained 
