468 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



and adding three quarts of strong alcohol. The mass is to 

 be frequently shaken up, and finally placed in a warm situa- 

 tion until it settles. Plants coated with this varnish will, it 

 is said, be protected from destruction by insects, and will re- 

 tain their colors fresh and unchanged. This varnish does not 

 peel off, and therefore, can be applied very thin. 5 C\ xxviii., 

 224. 



TAR TARNISH. 



An Englishman (Mr. Barker) has recently turned his atten- 

 tion to the manufacture of a kind of tar varnish, which is pre- 

 pared by taking equal parts, by weight, of the refuse of coal- 

 tar oils remaining after distillation, or treatment of the latter 

 for-the production of carbolic acid or naphtha, and of pitch or 

 other equivalent substance, and combining with them about 

 seven and a half parts, per cent., of chloride of sodium (common 

 salt). These ingredients are then mixed with water, and the 

 whole boiled together ; the water and salt in solution are then 

 drawn off from the pasty mass which has resulted from the 

 operation of boiling, and a quantity of fresh water is added 

 to the latter. The mixture is boiled, allowed to settle, and 

 the water drawn off. The mass may be boiled or heated a 

 third time ; but this is rarely necessary, and, if considered 

 desirable, sulphuric acid or other suitable drying agent may 

 be added thereto. The proportion of common salt above 

 mentioned is that which is preferred, and which is found 

 most advantageous in practice, but it may be used in equal 

 proportion to the other ingredients, and caustic soda may 

 also be employed in the same proportion as the common salt, 

 and either separately or in combination therewith. 8 A, 

 August, 1870, 152. 



PURIFICATION OF TURPENTINE, 



The use of turpentine for cleaning gloves and other articles 

 is materially interfered with by the unpleasant smell which 

 remains behind, no matter how well rectified the turpentine 

 may be. According to a recent French patent, this smell 

 may be entirely destroyed by the distillation of the turpen- 

 tine over tannin. Articles cleansed with turpentine thus 

 treated are to be heated in a tub to a temperature of about 

 140, by which, according to the statement of the patentee, 



