74 Transactions of the Royal Microscopical Society. 



is twenty-four hours for hardening (keeping the glass level), and 

 then another square of glass fastened on to it by strips of paper at 

 the edges, with small pieces of card at the corners to prevent contact, 

 and it makes an admirable lantern transparency. 



In the same way the drawings of other observers may be copied ; 

 by simply laying the ground glass upon them, the figures are seen 

 through, and may be well and accurately drawn. In this way I 

 have prepared some of Dr. Beales' most complicated drawings for 

 the screen, and enlarged them to 12 or 14 feet, preserving every 

 detail ; while a little crimson, lake, and prussian blue, used with a 

 sable pencil, give all the effects of staining. 



I forward two specimen transparencies chosen promiscuously 

 from a large number of drawings from hfe. [These were exhibited 

 to the meeting.— Ed. ' M. M. J.'] 



