The Microscope. 17 



(d). A solution of picric acid. 



100 cc. of a cold, saturated solution of picric acid. 

 2 cc. of concentrated sulphuric acid. 



Filter, and add 

 300 cc. distilled water. 

 Label. — Kleinenberg's Picric Acid Solution, 

 (e). Clove oil; turpentine oil; xylol or benzolene; spts. chloro- 

 form; Canadian balsam; hydrochloric acid, cone; 

 wax, hard and soft. 

 The latter is yellow wax to which enough Venetian turpentine 

 has been added to give it the consistency of putty. 

 (/). Paraffin e. 



Several ounces of each of those, having melting points at 45*^ 

 and 55*^ C, or the hardest and softest to be had in the shops. These 

 are to be mixed according to the temperature of the work-room, 

 usually two parts of the hard to one of the soft. 



(g). Alcohol of 70 per cent., 95 per. cent., and absolute (Squibbs) 

 strength. 



(h). A thin solution of pure India rubber in chloroform or 



benzene (Threfall). 

 {i). A thin solution of shellac in absolute alcohol. 

 (j). Gun cotton collodion. 



Gun cotton (photographer's) 2 grams. 



Sulphuric ether 15 cc. 



Alcohol, 95 per. cent 10 cc. 



Clove oil 100 cc. 



Dissolve the gun cotton in the ether and alcohol, add the clove 

 oil, and filter. (Gage.) 



(A;). Borax carmine. 



1 litre 70 per cent, alcohol. 



1 litre distilled water. 



25 grams carmine. 



40 grams borax. (Grenacher.) 

 Cook over a water-bath, and when cool, filter. Keep in a well- 

 corked bottle. 



(l). Alum carmine. 



100 cc. of a five per cent, aqueous solution of alum. 



1 gram carmine. 

 Boil, and when cool filter ; add a few drops of carbolic acid; 

 cork tight. (Grenacher.) 



