1900] MICROSCOPICAL JOURNAL. 147 



much use. Ground glass may be easily prepared by plac- 

 ing some fine emery powder between two pieces of glass 

 and then rubbing the glasses together for a few minutes. 

 If the glass becomes too opaque it may be rendered more 

 translucent by rubbing some oil upon it. 



Lacquer. — One of the principal reasons for using lac- 

 quer on microscopes is to protect the metal from oxida- 

 tion. Lacquer is readily soluble in alcohol, and great care 

 should therefore be taken when using this reagent. The 

 practice of cleaning the brass work of the instrument 

 with alcohol is, therefore, unwise. — Knowledge. 



MICROSCOPICAL SOCIETIES. 



Royal Microscopical Society. — On March 21, a micro- 

 scope presented by Mr. F. R. Dixon-Nuttall was referred 

 to by Mr. Nelson, who said it wasa microscope made by Ben- 

 jamin Martin, dating about 1765. A solar projecting ap- 

 paratus was packed in the same box. This was the inven- 

 tion of Dr. Lieberkuhn, who brought it to London in 1740. 

 Huff improved it by adding the mirror in 1743. It was a 

 very well-made and perfect example. Mr. Nelson called 

 attention to a number of microscopes which had been sent 

 for exhibition. The first noticed was by Plossl. The fel- 

 lows were asked to inspect the coarse adjustment, which 

 is very peculiar. The milled heads were of large diameter ; 

 a projecting stud was fitted on the inner side of each. From 

 these studs descended a pair of links connecting them to 

 similar studs fitted on to the sides of the body of the mi- 

 croscope. On turning the milled heads, the pins moved 

 through an arc, and thus raised or lowered the body of the 

 instrument. The next five microscopes were sent for ex- 

 hibition by Messrs. Spiers and Pond. One, -a French mod- 

 el, had a push-tube coarse adjustment and a short lever 

 nose-piece fine adj ustment. A vertical slot was made in the 

 outer tube or sleeve to allow the fine adjustment to move 

 up and down when the coarse adjustment was being effect- 

 ed. Another, and smaller, instrument was fitted with a 



