9G 
Journal of the 
diatom in position while the film is quite dry ; then breathe on it; 
allow the film to dry again; then place another diatom, and so on 
till the line or pattern is finished. If any of the diatoms are 
thick or likely to be crushed, stick three bits of cover glass under 
the edge of the cover with gum, and place a dot of gum on each 
before placing the cover in position on the slide. This, when dry, 
will keep the cover in its place while introducing the balsam, 
before doing which allow a little benzine to run under by capillary 
attraction, which soon displaces the air from the diatoms. Then 
apply a little balsam to the edge of the cover and a bit of blotting 
paper to the opposite edge. This draws away the benzine, and 
the balsam follows and takes its place. Another plan is to gum 
a piece of good cream-laid paper on the slide, centre on the turn¬ 
table, and make two cuts through the paper, removing the middle 
and outer portions and leaving a ring of paper to form a cell as 
large as the cover; then cut two small openings in opposite sides 
of the ring, gum the top of the cell and insert the prepared cover 
on the gummed surface. When dry apply benzine to one of the 
small “ sluice gates,” and then balsam as before. Put the slide in 
a warm place for several days, and finish off with white, black or 
coloured varnish to fancy. 
Winter is the best time for the dry mounts, as the breath dries 
off too soon in hot weather; and summer is the best for the 
balsam mounts, as it is difficult in winter to keep the breath from 
moistening the isinglass at the wrong time. The cement cells 
should be quite dry and hard before mounting, or a dewiness will 
appear and ruin the object. Soften the cement over the lamp, 
press the cover down till it sticks all round, let stand a day or two 
and finish off. No doubt the diatoms would be more secure if 
burnt on the cover in the dry mounts, and possibly that process 
would be sufficient for the balsam mounts without the film of 
isinglass, as stated on p. 68 of Davies’ Manual of Mounting. 
Mr. Sharp has tried several kinds of mechanical finger, but 
declares he “ can do the work quite as well and in less than half 
the time ” by the method described above. He has sent specimens 
of scales and diatoms mounted according to the above directions, 
and although he says they are a long way from his best, they are 
certainly all that could be desired as proof of the efficacy of the 
plan. 
