98 ANNUAL OF SCIENTIFIC DISCOVERY. 



formed by the letters seen through the holes, and which of course 

 correspond with those punched out of the other sheet. Should the 

 dispatch be found on its way, it is of course nothing more than a 

 sheet of white paper punched with holes, conveying no intelligence 

 without the printed sheet. 



NEW USES FOR PAPER, 



The village of "Wallsend, England, is lighted with gas conveyed 

 through pipes made of paper bituminized. These pipes possess 

 great strength, durability, and inoxidibility, with the advantage of 

 being about one-fifth the weight of iron pipes, and about thirty-five 

 per cent, cheaper. The process of the manufacture consists in caus- 

 ing a roll of paper to pass through a reservoir of melted bitumen, 

 after which it is tightly coiled round a mandril to any required thick- 

 ness ; thus, when hardened, a tube of perfect texture, great hardness, 

 and enormous strength, is formed. These pipes are also to be used 

 in laying about five miles of the gas pipes in Sunderland ; and there 

 is every probability that they will speedily come into general use. 



At the International Exhibition, London, 1862, paper pipes made 

 water-proof were exhibited, which were warranted to endure a press- 

 ure of one hundred and sixty pounds per square inch, and to be 

 indestructible by ordinary influences, either under ground or in open 

 air. The same exhibitor also showed paper boards, prepared in the 

 same way as the pipes above mentioned, which he stated were much 

 stronger and only half the price of oak. They could be made of 

 any thickness or size, and Avere applicable for the construction of 

 stables, outhouses, sheds, pontoons, gunboats, etc. Messrs. Green & 

 Co., of Cork, Ireland, exhibited brown paper prepared for roofing, 

 rendered impenetrable to water by tar, of low cost, and warranted 

 to wear for twenty years. 



COMPRESSED COAL. 



The question of the compression of coal has engaged the attention 

 of mechanical and scientific men for many years, the great difficulty 

 having been to bring about the desired result without the admixture 

 of extraneous cohesive matter. By the amalgamation of several 

 inventions, an English company according to the London Mining 

 Journal have at last reached the coveted goal, being able to com- 

 press the finest coal into blocks which occupy two-thirds the space 

 of ordinary coal, taking but thirty-one cubic feet to the ton, while 

 raw coal averages from forty-four to forty-eight feet. The process by 

 which these compressed blocks are obtained, says the Journal, is inex- 

 pensive, and without complication. In the first place, the pure coal- 

 dust, or slack, is conveyed through a washing machine, for the pur- 

 pose of disconnecting it from any stony particles it may contain. It 

 is then subjected to a steady heat, until its bituminous parts are ren- 

 dered quite soft, after which it is passed into a moulding machine. 

 This comprises a rotary table containing the moulds, around which 

 are situated three presses namely, the feeder, for filling the mould ; 

 the main press, for condensing the block; and the discharger, which 

 removes the block out of the mould, whence it falls into a travelling 



