60 Warington^ 0??. Additions to his Microscope. 
scavengering adjunct^ maintaining the water^ &c._, in a con- 
tinual healthy condition. A small and permanent bottle 
aquarium or miniature tank is thus formed^ in which the 
objects to be investigated can become naturalised, and the 
whole vessel, with its contents, brought under microscopic 
observation, without disturbance, at the will of the operator. 
In carrying these contrivances into practical working, I 
found that the external surface of the ordinary cast or 
moulded square bottles was so uneven, from the chilling of 
the glass by contact with the mould in the process of manu- 
facture, that it was qiiite impossible to obtain anything like 
accurate observation ; it was therefore necessary to employ a 
glass vessel having a very smooth or a ground and polished 
surface, so as to obviate these evils. I also found that the 
ordinary large cells, cemented, as is usual, with marine glue 
or with shell-lac or other varnish cement, were very difficult 
to maintain water-tight for any length of time, the fluid ap- 
pearing gradually to penetrate between the surfaces of the 
glass and the cement, causing the whole after a short interval 
to become useless. I have consequently had a light rectan- 
gular framing of zinc constructed, into which, after being 
well painted, the ordinary thin window glass is cemented, 
and this appears, as far as my present experience extends, to 
answer the purposes required very efficiently. 
The second part of this contrivance consists in con- 
structing a sort of stool or small table, to which the micro- 
scope could be attached, and on the stage or platform of 
which the small aquarium could be readily transferred. The 
first table of this kind which I had made was exhibited at 
the microscopic soiree of the Society of Apothecaries, in the 
spring of 1857. It was constructed of well- seasoned deal, and 
had the following dimensions : the top {a, fig. 2) was six inches 
across by the same width ; the shelf (b) of such a thickness 
as to allow of the clamp being easily attached ; the foot (c) 
eight inches long, the width being the same as the top ; the 
sides [d d) ten inches high by four wide. It will be, however, 
readily perceived, that these dimensions and the general 
construction may be altered to suit the convenience or taste 
of the individaal. 
Having found these arrangements very useful and available 
for many points of research, the next object for improvement 
that suggested itself was to endeavour to construct this table 
out of the parts of the microscope and its packing box ; and 
I may mention that Mr. King, at my suggestion, so con- 
structed the box, for my portable microscope, manufactured 
by him for Messrs. Pastorelli, as to render it capable of being 
