42 THE MICROSCOPE 



removed from the fire and well beaten in a mortar and moulded 

 in the hands until of the consistence of putty. It may then be 

 coloured with vermilion or other colours. This cement is quite 

 safe for mounting large and thick objects in fluid, as it rarely gets 

 hard. 



Caoutchouc Cement.— Caoutchouc, cut small, J oz. ; mineral 

 naphtha, i pint. Dissolve with heat, and add shellac, | oz. This 

 cement requires great care in making. 



Resin and Balsam Cement. — Resin, 2h oz. ; bees'-wax, ^ oz. ; 

 Canada balsam, i drachm. Dissolve with heat and mix. When 

 wanted for use, it must be rendered mouldable by the action of 

 heat. It is a strong cement. 



Good Black Varnish.— Mix well in a mortar some lamp-black 

 and gold-size. It makes a good tough finishing varnish. Gold- 

 size, when added to Brunswick black, renders it less liable to crack. 

 It is better to keep nearly all the cements some time before use. 



Mastic and Bismuth. — Dissolve gum mastic in chloroform, and 

 thicken with nitrate of bismuth. The solution of mastic should 

 be nearly saturated. 



Kitton's Cement* is made of equal parts of white lead, red 

 lead, and litharge, all in powder. Grind together with a little tur- 

 pentine until thoroughly incorporated, and then mix with gold- 

 size. The mixture should be thin enough to use with a brush. 

 In using, one coat should be allowed to dry before applying 

 another. No more cement should be mixed with the gold-size 

 than is required for immediate use, as it sets quickly and becomes 

 unworkable. For balsam or glycerine-jelly mounts almost any 

 varnish will do, but for fluids, glycerine, etc., it is necessary to 

 have one tough, which will prevent leakage. 



Liquid Glue.— Dissolve shellac in wood naphtha at a very low 

 temperature, until the mixture is of the required consistency. It 

 makes a very brittle varnish, but is improved by the addition of a 

 little glycerine and makes very good cells. 



Guaiacum Varnish.— Gum guaiacum, 2 ounces; shellac, 2 

 ounces ; methylated spirit, 10 ounces. Powder the guaiacum and 

 dissolve it in the spirit, filter and then add the shellac. Keep the 



* Moiitldy Microscopical Journal, Oct., 1876. 



