96 ANNUAL OF SCIENTIFIC DISCOVERY. 



coal, and 1 parts of slaked lime. It is veiy solid, and its color is 

 dark. 



Preserving the Bottoms of Iron Ships. Welch's preservative 

 cement is the last of the many compositions tried in England for pre- 

 serving the bottoms of iron ships. It is an elastic cement composed 

 of certain stone grits and bituminous substances, and with this the 

 ship's bottom is coated with a layer about one-thirty-second of an 

 inch thick. When firmly set, a liquid cement is laid on with a 

 brush, and on this latter is transferred a metallic facing of copper- 

 dust, a liberal dusting of the copper facing with fine stone grit 

 completing the process. Two vessels partly coated with this 

 composition, just returned from a twelve months' voyage to 

 China, were covered with barnacles except where the composition 

 was applied, which was perfectly clean, and presented the ap- 

 pearance of bright copper. 



Preserving Polished Steel from Rust. It is said that nothing is 

 equal to pure paraffine for preserving the polished surface of iron 

 and steel from oxidation. The paraffine should be warmed, 

 rubbed on, and then wiped off with a woollen rag. It will not 

 change the color, whether bright or blue, and will protect the 

 surface better than any varnish. 



Cement for Coal-dust Fuel. One of the best cements for the ag- 

 glomeration of coal-dust fuel is said to be that used in several 

 continental establishments, consisting of coal tar, gluten, and 

 starch. The quantities of these substances are altered according 

 to the qualities and properties of the coal dust ; but they are very 

 easily ascertained by a few experiments. About 2 per cent, of 

 this mixture (say, containing 2 parts of coal tar, 1 part of gluten, 

 and one-half part of starch) would be suitable for coal dust of an 

 average quality of bituminous coal. 



Deodorization of Vulcanized Rubber. The offensive sulphurous 

 smell of India-rubber goods is a serious drawback upon their other- 

 wise great convenience. Mr. Stephen Bourne, an Englishman, has 

 patented a process for removing this odor by treating the fabrics 

 in a heated chamber with charcoal, and, in preference, animal 

 charcoal, as more rapid in its effect. The operation may be con- 

 ducted simultaneously with the vulcanizing, the apparatus re- 

 quired being very simple. Scientific American. 



A Process for Deodorizing Petroleum Oil. That very industrious 

 technical chemist, Dr. R. Wagner, tells us that the disagreeable 

 odor of petroleum oil can be taken away by treating the oil with 

 a solution of plumbate of soda. This is only a solution of oxide 

 of lead in caustic soda, and will certainly remove all such odor as 

 sulphur compounds might communicate to the oil. 



Paper and Alcohol from Wood. A company at Geneva, Switz- 

 erland, has commenced the manufacture of paper and alcohol 

 from wood, by a method which appears to be an improvement on 

 the other processes employed for the same purpose. The fibre is 

 first treated with sulphuric acid, with the usual result (formation of 

 glucose, and, by fermentation, of alcohol) ; but the pulp also 

 acquires a somewhat glutinous consistence, which must be of de- 



