40 

 ABSTRACT OF A PAPER 



BEAD BY 



W. GROVES, Esq., 



THE PREPARATION OF SPECIMENS FOR THE 

 MICROSCOPE, 



23kd NOVEMBER, 1881. 



Mr. Groves exhibited a variety of instruments, which he had 

 found useful in the work, and recommended the ordinary turn- 

 table to be fitted with stops, so as to facilitate the operation of 

 laying correctly successive coats of varnish rings on the slides ; 

 and advised the use of caustic potash in cleaning Polycystina, as 

 he had never found any injurious effects result from boiling them 

 in a strong solution of potash. 



A caution was given against putting chlorate of potash into 

 sulphuric acid, and then applying heat to the mixture when 

 cleaning Diatomace«, &c., as an explosion was in that case 

 inevitable, but he stated that he had never found any danger arise 

 from dropping small quantities of that salt into boiling acid. 

 He also pointed out the danger of diluting the acid while hot. 



He cautioned Microscopists against explosions caused by 

 retarded ebullition ; this occurred under certain conditions, when 

 boiling (in a glass tube for instance) was stopped and heat again 

 applied to the vessel containing the liquid ; the heat often 

 accumulated in such cases without ebullition re-commencing for 

 some time, the accumulated heat causing the explosions. 



He described the process of getting rid of air bubbles in 

 objects mounted in Canada Balsam, the method adopted being to 

 mount in rather fluid Balsam, and to allow the slides to remain 

 covered, so as to exclude dust until the bubbles disappeared, 

 which usually took place in a few days. 



Many other items of information were given of importance 

 to those desirous of preparing specimens for the Microscope. 



