REARING OF INSECTS FOR CABINETS. 19 



berecl that the impression is taken on the side of the paper opposite to 

 that which was washed with the sohition. Enough of the bi-chromate 

 soaks through to answer every purpose, and the surface on that side is 

 not rubbed up by the contact of the sponge, which would make a mate- 

 rial difference in the beauty of tlie impression. 



In order to fix the drawings, take a large flat vessel — a waiter answers 

 the purpose — and cover the bottom with them placed side by side. Pour 

 on water to the depth of half an inch and let it stand some minutes^ 

 Then take each sheet separately, and after agitating it in the water a little 

 while, lay it on a thin board or the back of a small waiter, and inclining 

 it pour water on it from a pitcher, at a highth of about a foot, turn the 

 paper and repeat the process, till the water which conies off is perfectly 

 clear without any tinge of the salt. Lay each sheet as finished over a 

 string, and when perfectly dry, subject them to a moderate pressure in 

 order to smooth them, they may then be kept for any length of time, 

 care however being taken not to expose them unnecessarily to a bright 

 light. 



The theory of the process is very simple. The bi-chromate when 

 first applied to the paper is of a yellow colour and very soluble, expo- 

 sure to the sun turns it brown and makes it insoluble. When therefore 

 the object is placed on the paper, the uncovered parts is darkened, while 

 that which is covered remains more or less yellow, according to the 

 opacity. The washing takes out the soluble yellow parts, leaving the 

 original white contrasting with the brown. The lights and shades are 

 of course reversed as in most of the processes. 



The whole expense both of time and money is very small. Paper 

 can be bought for 12| cents the quire, quite good enough for the pur- 

 pose, and a quarter of a pound of the bi-chromate of potassa, at 12^ cents, 

 will prepare four quires of paper. I have made sixty photographs of 

 drawings, each consisting of half a sheet of foolscap, in a few hours, and 

 washed and finished them in less than that time. When there is a great 

 deal to do it is better to have two frames at work as then while one is in 

 the sun, the odier can be got ready. 



ON THE REARING OF INSECTS FOR CABINETS, 



The rearing of butterflies from the larva state is a very interesting 

 pursuit for the Entomologist. He then has the opportunity of observing 

 all the maneuvers of the.se wonderful little creatures in undergoing their 

 transformations, and in this way only can he procure the best specimens 

 for his cabinet. Butterflies captured in the field are apt to be somewhat 



