MAEINE ANIMALS AS LANTERN SLIDES. 271 



paper round the edges, and, after this has dried, by var- 

 nishing it, and, when the varnish is hard, by glueing strips 

 of black paper round the slide, the soft balsam may be so 

 confined as not to run out; but it seems probable that, by 

 a modification of the process, the balsam may be made 

 sufficiently hard before the glass cover is put on, so as to 

 greatly reduce the risk of leakage, which, without care, 

 may be very troublesome. Excellent results can be 

 attained, but it is very desirable that the necessary pro- 

 cesses should be materially simplified, and made more 

 certain. 



