366 REAGENTS AND THEIR PREPARATION [Ch. X 



It must be applied to unwaxed or unvarnished wood. If wax 

 paint or varnish has been used on the tables, that must be first 

 removed by the use of caustic potash or soda or by scraping or planing. 

 Two solutions are needed: 



Solution A 



Copper sulphate 125 grams 



Potassium chlorate or permanganate 125 grams 



Water 1000 cc. 



Boil these ingredients in an iron kettle until they are dissolved. 

 Apply two coats of the hot solution. Let the first coat dry before 

 applying the second. 



Solution B 



Anilin oil 1 20 cc. 



Hydrochloric acid 180 cc. 



Water 1000 cc. 



Mix these in a glass vessel, putting in the water first. Apply two 

 coats without heating, but allow the first coat to dry before adding 

 the second. 



When the second coat is dry, sandpaper the wood and dust off the 

 excess chemicals. Then wash the wood well with water. When 



dry, sandpaper the surface and then rub 

 thoroughly with a mixture of equal parts 

 turpentine and linseed oil. The wood may 

 appear a dirty green at first, but it will soon 

 fc, ' = gp-^ become ebony black. If the excess chem- 



Fig. 215. Drying rack icals are not removed the table will crock. 



with Inclined Pegs for ^n occasional rubbing with linseed oil and 

 Bottles. . 



turpentine or with turpentine alone will 



clean the surface. This is sometimes called the Danish method, 



Denmark black or finish. See Jour. Ap. Micr., Vol. I, p. 145; Bot. 



Zeit., Vol. 54, p. 326; Bot. Gazette, Vol. 24, p. 66; Dr. P. A. Fish, 



Jour. Ap. Micr., Vol. VI, pp. 211-212. 



§592. Zenker's fluid. — Miiller's fluid (§581) 100 cc; mercuric 



chlorid 5 grams. Just before using add 5 cc. of glacial acetic acid 



to each 100 cc. of the above. Fix fresh tissue 5 to 24 hours. Wash 



