MECHANICS AND USEFUL ARTS. 95 



of wood. All of it, save where the sculler sits, is gas-tight, so 

 that in the event of a race sufficient gas may be taken into it to 

 reduce its weight to 8 pounds. The displacement of water by- 

 such a craft will be very much less than that of a wooden boat, 

 and the same exertion will propel it proportionately faster. Its 

 strength is also a great advantage. 



SULPHURIZED PAPER. 



This invention as patented by Charles F. Crehore, of Newton, 

 Mass., consists in subjecting the paper to the action of sulphur, 

 preferably to immersing it in a bath of boiling or melted sulphur, 

 the temperature of which is to be regulated by the required hard- 

 ness of the finished material. The action of the sulphur has the 

 eftect of rendering the paper hard, semi-elastic, and water-proof, 

 as well as compact in body, and with a susceptibility of high 

 finish, if desired. Among the various instances of application of 

 which the invention is susceptible, so far as the experiments made 

 have proved it a success, a particular one is its use as press-paper 

 for cloth printers' use, as well as for those of ordinary printing, 

 the advantages of which will at once manifest themselves to per- 

 sons skilled in the craft. For book-binders' use the requisite 

 amount of rigidity may be obtained with great reduction in bulk 

 and weight, and, as a consequence, in cost, as compared with the 

 material now in use. 



NEW CEMENTS. 



Few things are in more constant demand among mechanics 

 than cements, and it must be admitted that most of those in com- 

 mon use are open to improvement. We have recently met with 

 some recipes in the French and German journals, which we put 

 together for the information of our readers : 1. The first is an iron 

 cement, which looks likely to be useful. It is made by mixing 

 from 4 to 5 parts of dry cla}^ 2 parts of iron filings, 1 part oxide 

 of manganese, half a part of salt, and half a part of l)orax. When 

 the cement is wanted for use, this mixture is made with water 

 into a paste, which is applied immediately to the pieces to be 

 joined. It is then allowed to dry gradually, and is subsequently 

 heated to whiteness. After this the cement will resist water, and 

 of course heat. 2. Another, said by Stinde to be a very useful 

 cement, is made by mixing equal parts of oxide of manganese 

 and oxide of zinc, and making them into a thinnish paste with the 

 solution of silicate of soda of commerce. This paste must be ap- 

 plied quickly, as, no doubt, it sets very rapidly. It is not calcu- 

 lated to resist heat and water; the latter, at all events, not for 

 any length of time. 3. Another recipe we find is for a strong 

 liquid glue. To make this the inventor puts 3 parts of glue with 

 8 parts of cold water, and lets them stand for several hours to 

 soften the glue. He then adds half a part of muriatic acid and 



