346 History of Mechanical Inventions and 



cotton or flax ; and when smooth surfaces are wanted, the substance must 

 be pressed between polished metallic plates. 



5. Account of an Improvement on Ropes. By Mr Thomas Hancock. 



This invention, also secured by patent, consists in soaking the strands of 

 strand ropes and cordage in the juice of the tree called Hevcea, which grows 

 in South America and in the East Indies. It has the consistency of cream 

 when it first flows from the tree, and, with the exception of its not being 

 heated, it is used in the same way as tar. Several coats may be laid on the 

 outer surface of the cords before the preceding coat has dried. The ropes 

 are then placed in a drying room till they cease to be sticky. When thus 

 made, they will last much longer than ordinary ones. 



6. Method of making Impressions on Steel Plates. 



A mould having been formed of the object to be impressed upon the 

 steel, a mixture of one pound of brass, and five ounces of pewter, in a fus- 

 ed state, is poured upon the mould. The piece of steel to be impressed 

 being wetted with turpentine, it is covered with blotting paper, and the 

 whole is enveloped in earth in order to preserve the polished surface of the 

 steel from oxidation by the air. The steel being brought to a red heat, is 

 taken out of the fire, and the earth being removed, the composition cast 

 is imprinted upon it by a powerful pressure. In a similar manner may im- 

 pressions be executed on brass, or any of the metals. — Hollander's Meial- 

 lurgico-Technological Journal, quoted by Mr Newton in his Journal of 

 Arts. 



7. Description of Improved Axlelrees. By Mr William Mason. 



The object of this contrivance is to prevent the wheel of a carriage from 

 coming off by accident. For this purpose, the end of the axletree terminates 

 in a screw, upon which a nut is screwed in nearly the usual way. In the 

 screw, as well as in the nut, there are several semicircular grooves cut 

 across the threads in the direction of the axis of the screw. The conse- 

 quence of this is, that when the nut is screwed home, a cylindrical hole is 

 formed whenever two semicircular grooves come opposite each other. In- 

 to these holes a pin or bolt attached to a collar is introduced, so as to lock 

 together the nut and the screw. — See Newton's Journal of the Arts, June 

 1S26, p. 309. 



8. Account of the Viiruvian Cement for building and other purposes. An 

 invention communicated to Mr J. P. Beavan by a Foreigner. 



This cement, for the exclusive privilege of manufacturing, which a patent 

 has been obtained, consists in mixing together, and sifting through a very 

 fine sieve, one part of pulverised marble, one part of pulverised flint, and one 

 part of chalk ; to this is added one other part of lime, which has been slacked 

 at least three months. The whole being made into a thin paste with water, 

 is spread as thinly as possible over a rough coarse ground, and reduced by 



