NOTES AND QUERIES. 297 
posite and equidistant from the centre, two circular plates or discs, 
one inch in diameter, are set, their surfaces flush with that of the 
large plate. Pivots from the two discs project through the plate, 
and each carries upon the lower side of the plate a toothed wheel. 
A hollow sleeve, rotating free from the stem of the table, carries - 
a third and larger wheel, which gears into the two others, and 
thereby gives rotation to the discs in the top of the plate. 
Near the opposite edges of the two discs, the angular jaws which 
hold opposite corners of the slide are pivoted (as in Cox’s and 
other forms of tables), and it will be seen that by giving rotation to 
the’ central wheel, under the plate, the jaws may be made to 
approach or recede at pleasure. 
A coiled steel spring, concealed within the hollow sleeves serves 
to close the jaws, while the single motion of a milled head upon 
the sleeve opens them to their full extent. 
It will also be found, that although the jaws do not approach in 
a straight line, yet, when properly adjusted, a line joining the 
pivots of the jaws will cut the centre of the plate, whatever the 
position of the jaws; and they being always equidistant from the 
centre, it follows that the slide, when clasped between them, must 
be perfectly centered. 
For the purpose of re-touching old slides, the ordinary clip- 
springs are retained. 
The price of this Turntable is six-and-a-half dollars, or equal 
to twenty-seven shillings of our money. 
INFuSORIA.—We have lately received some interesting tubes 
from Mr. Bolton, one of which, containing a sprig of AZyriophyllum 
spicatum, was exceedingly rich in organisms. We found JZelicerta 
ringens, Limnias ceratophyllt, Floscularia cornuta, Philodina megal- 
stricha, together with many species of Vorticellidze. 
The weed was culled from a river pool near Stourbridge, yet it 
contained the reputed brackish-water diatom Bacillaria paradoxa. 
There were also many Choano-Flagellate monads attached to 
the weeds and to the various organisms. 
GLYCERINE Mounts.—I have had much bitter experience with 
preparations mounted in glycerine, which suffer injury from clum- 
siness in handling, more than the fault of expansion ; for after a 
preparation has been mounted two or three years, the cement 
becomes very hard, and if injured by a fall, or knock against the 
microscope, starts a leak. The number of preparations ruined by 
my customers in this and other ways, prompted me to find a 
remedy, or to lesson the chance of injury. I have now devised 
the metal caps, which so far have stood the heavy thumps of the 
Post-office men, and all the clumsy treatment which many give 
them. The caps are made to fit Pumphrey’s vulcanite cells, as 
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