Glass capsules (Fig. 8) are made in different sizes, ranging from 1½ in. to 3 in. in diameter, with a height of 1 in. or 2 in. The largest size, 3 in. by 2 in., costs 5d., and a glass circle to cover it, 1d. These capsules will be found useful for small aquaria, and for isolating aquatic larvae in order to keep them under observation during their change to perfect insects. It was in a capsule of this kind that some of my Ptychoptera larvae (p. 184) were kept, and changed into the pupal condition.
The glass block, with cover (Fig. 9), is convenient for a number of purposes. In it small creatures may be examined in air or in water, and it makes an exceedingly convenient little dissecting dish for use with the mounted hand magnifier (Fig. 1), or with Leitz’s stand (Fig. 3), or the home-made stand (Fig. 6). The glass box, with cover (Fig. 10), is extremely good for keeping small creatures under observation.
Fig. 9.—Glass Block, with cover.
Fig. 10.—Glass Box, with cover.
Excavated glass slips, 3 in. by 1 in., may be bought from any optician. They serve for the examination of objects in water, and also for dissection. The best I have been able to get have been supplied by Mr. J. Hornell, of the Biological Laboratory, Jersey, and they are very cheap.
We shall need some forceps to pick up specimens from the vessels in which they are kept, and the same little instruments will be found convenient in collecting. Both forms have advantages of their own; if we are limited to one pair, they should be curved, and of brass. Forceps with ivory tips are very useful for handling aquatic vegetation. These articles are not usually sold by opticians, but are kept by the tradesmen in Clerkenwell who sell jewellers’ and watchmakers’ tools, and cost from 1s. to 1s. 6d. a pair.
Fig. 11.—Forceps.