MECHANICS AND USEFUL ARTS. 131 



was submitted to a strong ciuTent of atmospheric air strongly- 

 compressed. This current of air is said to convert the sulphur 

 into sulphuric acid and remove it. The coke is reported to pro- 

 duce iron equal to that which has been made with wood charcoal. 



— Quarterly Journal of Science, July. 



In Great Britain, the quantity of coal-dust remaining unem- 

 ployed is calculated at 28,000,000 tons. Various methods have 

 been attempted to convert it into useful fuel by compressing it 

 into cakes, but the operation is not sufl3.ciently remunerative. >Iq 

 Belgium they employ another plan which seems to answer better. 

 They mix coal-dust with 8 per cent, of tar, and then press into 

 cakes, which are found to make excellent fuel for steam-engines. 



— Mech. Mag., July 9. 



An Explosive Dye. — The artificial saffron, invented by Mr. 

 Millonsweg, of Poblitz, has of late been found to be as easily 

 exploded as gunpowder, though possessing 40 per cent, less of 

 projectile force. 



Moss Rubber Inking Boiler. — The editor of the "Mechanics' 

 Magazine," London, speaks very highly, from his own experience, 

 of the above-mentioned article, which is invented by Mr. Stephen 

 Moulton, of Bradford-on-Avon, and prepared in the following 

 manner : Vulcanized India-rubber is reduced to a powder, then 

 placed in a mould, and subjected to a second vulcanizing heat, 

 wliich converts it into a mossy substance. This core is now 

 covered with skin of rubber, which is then vulcanized, and the 

 roller is then ready for use. 



Lining for Fire-Proofs. — There was exhibited, at the last 

 meeting of the Institute, a new material, which, by its remarka- 

 ble power of non-conduction, presents especial advantages. This 

 was devised and patented by Mr. W. Alford. It consists of a 

 rough papier mache, made of old wall paper, by moistening and 

 compressing it. Its power of resistance to fire was illustrated by 

 a specimen exhibited on this occasion, which had been exposed, 

 as a lining to an iron-box, with a wooden one in the centre, to 

 the heat of a brightly burning anthracite fire, for the space of an. 

 hour. The material was charred, on the outer surface, to the 

 depth of about one-fourth of an inch, while all the rest, and the 

 box, of course, within, was perfectly intact. This substance has 

 been favorably reported upon by many of our safe-builders, and 

 seems to be an admirable invention. 



Fire Alarm, by M. Diou. — At the last meeting of the Institute, 

 there was presented by Mr. J. Dcmorat, for exhibition, an im- 

 proved fire-detector, manufiicturcd by the American Fire Detector 

 Company, 725 Broadway, New York. 



This apparatus consists of two parts, one of which is placed in 

 the location where the presence of fire is to be detected, and the 

 other where the alarm is to be given. These are connected by 

 wire, in the manner of ordinary bells, except that the wire is 

 tightly stretched in its normal condition. The first instrument 

 consists, essentially, of a catch (holding one end of the wire), 

 controlled by a copper-helix, whose expansion will liberate the 

 catch, and thus slack the wire. The other instrument consists of 



