376 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



RENDERING WOOD LESS COMBUSTIBLE. 



Mr. A. Patera recommends the solution of the following 

 substances in water for the purpose of application to wood 

 to render it incombustible, experiments with all being equal- 

 ly satisfactory: 1. One third part of sulphate of ammonia, 

 and two thirds of sulphate of lime (gypsum). 2. Equal parts 

 of borax and Epsom salts. 3. A concentrated solution of 

 soluble glass, without any admixture. Wood supplied with 

 a coating of any of these solutions, according to Mr. Patera, 

 will be measurably protected against the spread of fire. 

 18(7, 1871, xvi., 127. 



CLEANING SOILED MARBLE SLABS. 



Much annoyance is frequently experienced by the soiling 

 of marble table-tops or other marble objects, and a perfectly 

 satisfactory method of removing such stains is still a deside- 

 ratum. It is said that if slacked lime be mixed with a strong 

 solution of soap into a pasty mass and spread over the spot 

 in question, and allowed to remain for twenty-four to thirty 

 hours, then carefully washed off with soap and water, and 

 finally with pure water, the stain will be almost entirely re- 

 moved, especially if the application be repeated once or twice. 



Another preparation consists in mixing an ox-gall with a 

 quarter of a pound of soap-boiler's lye, and an eighth of a 

 pound of oil of turpentine, and adding enough pipe-clay earth 

 to form a paste, which is then to be placed upon the marble 

 for a time, and afterward scraped off; the application to be 

 repeated until the marble is perfectly clean. It is quite pos- 

 sible that with all our endeavors a faint trace of the stains 

 may be left; but it is said that this will be almost ^appre- 

 ciable. Should the spots be produced by oil, these are to be 

 first treated with petroleum for the purpose of softening the 

 hardened oil, and the above-mentioned applications may be 

 made subsequently. 



Ink spots may be removed by first washing with pure wa- 

 ter, and then with a weak solution of oxalic acid. Subse- 

 quent polishing, however, will be necessary, as the lustre of 

 the stone may become dimmed. This can be best secured 

 by very finely powdered soft white marble, applied with a 

 linen cloth first dipped in water and then into the powder. 



