Scrapers.—In December, 1832, a patent was granted to Mr. John Bourne, for a machine for scraping and cleansing roads. The injury to a road accruing from an accumulation of loose mud on its surface, is so well known, that labourers are employed on all well-managed roads to scrape them when neces sary. The hand-scraper is so very imperfect an instrument, that many inge nious attempts have been made to construct machines for cleansing the road surface by sweeping or scraping. Mr. Brown's plan deserves notice for its simplicity. It is thus described in the Repertory of Patent Inventions :—" This machine is formed of a series of scrapers fastened to wooden rods, or bands, acting on a common axis, yet rising or falling singly and independently of each other, so as to meet the inequalities of surface. They are all inserted into a frame, the lower part of which passes ou the scrapers, the upper part being the handle ; the machine is then fixed on wheels, and the modle of using it is by band. The workman commences at a given place by elevating the handle, which sinks the scrapers, and he drags the machine across the road at right angles to the line of draught; when he has dragged the mud to the opposite side, he depresses the handle, and the scrapers rising, deposit their gatherings. The independent action of each scraper enables the whole to enter and cleanse out any holes or depressions of the surface, or to get over any hard projection ; and to adapt itself, generally, to any state of road, or to any kind of surface.
Very similar to Mr. Bourne's is a machine for the same purpose by Dr. Winterbottoin. Two pieces of timber, forming at one end a pair of shafts, are secured firmly by transverse braces. The iron plate, or front of the scraper, is fixed within the braces. A pole, or handle, made fifteen feet long, passes through strong holdfaets in the 'braces. This acts as a lever, by which the scraper may be raised or Bunk at pleasure. The person who holds it may direct the scraper, assist it to overcome obstacles, or give it, if necessary, additional pressure. The machine, when not in use, may be reversed, and is furnished with a sledge part, on which it slides when not in use. The method of using it is nearly the same as the one we have before described.
Mr. H. T. Cassell, of Mill Wall, Poplar, has obtained a patent for a bitu minous composition, called by him "lava stone." The patentee describes the merits of the invention to consist in the discovery of a mode of combining certain materials to form a species of stone uniting the advantages of metal with those of stone. The properties of this stone are durability and toughness. It does not absorb water, and is a non-conductor of heat. Each of these pro
perties can, in the process of combination, be increased or diminished, to suit the purposes for which the stone is intended. In paving a street, the following method is pursued :—Instead of disturbing the bottom, it is to be consolidated by picking, raking, and rolling. A coating of bituminous lava is then run over, and the whole rendered impervious to water. This coating is then to be paved over with granite stones of the usual description, and the interstices are to be filled in with hot bituminous lava. The whole street thus becomes one solid mass, and will need no repairs until the granite is worn too thin to sustain the weight of the passing traffic.
In using the "lava-stone" for the construction of roads, Mr. Cassell directs the road to be prepared by raking and rolling it till uniform and even. The lava carts are then to be brought on, and the lava-stone previously prepared is run hot from the carts to the depth of two, three, or four inches, according to ebb anticipated traffic. The hot lava uniting itself to the substrata of prepared ground, becomes one solid mass, and will not admit of the passage of any mois ture. A road thus formed, will last several years in good condition, and will always present one even surface. The patentee has published a small pamphlet, describing the various modes of using the "lava-stone," the different purposes to which he conceives it may be applied, and a table of prices. We must refer the reader to this pamphlet for further information.
Mr. Cassell's plan is not destitute of merit or originality ; but we think lie is too sanguine in his expectations of the results. Upon roads where the traffic is not very considerable, it will probably make an excellent, firm, and durable surface ; but on our great thoroughfares, the expense of the " lava-stone" would be an objection, as we are sure it must be laid on in much greater thickness than suggested by the inventor.
It appears to have been used with decided success on the Ferry-road, Mill Wall, Poplar, on the Vauxhall Road, on the premises of Messrs. Goding, the Ale Brewers, Mr. Giblett, of Bond Street, and many other places ; and we have before us a letter from Mr. Martin, the Secretary of the Vauxhall Bridge Com pany, in which the piece of road, laid with the lava, is spoken of in a very satis factory manner. An experiment hu been lately tried on the Whitechapel Road with this composition, which is certainly a failure ; it is, however, but justice to the patentee to state that the unfavourable circumstances under which the work was executed, sufficiently explain his want of success hi this case.