42 ANNUAL OF SCIENTIFIC DISCOVERY. 



The weight of the vessel sent by Mr. Balestier, is three and a quarter 

 pounds. Except at the centre, where a part, two inches over, is left 

 thick and flat for a base or foot to rest on, the thickness does not ex- 

 ceed, and in fact scarcely reaches, one tenth of an inch. The handles 

 are cast on, but appear to have been first formed and inserted into the 

 mould. This does not seem to have been of sand, as the inner and 

 outer surfaces are smoother, and of a different appearance, from iron 

 cast in that material. Of the metal used for repairing this pot, Mr. 

 Balestier has forwarded a lump that was not melted. It is part of an 

 old kettle, and differs but little, if any, from our pot metal. The cruci- 

 ble, not much larger than a thimble, is made apparently of the same 

 material as our common sand crucibles ; except the shape, it could not 

 l)e distinguished from one of them. The amount of one fusion seems 

 not to cover more than half an inch of the crack, and hence, in the piece 

 inserted, no less than nine distinct applications of the melted metal 

 are seen resembling in the inside so many ragged wafers touching 

 each other, while on the outside, where the metallic plaster was ap- 

 plied, there are the same number of rude protuberances. Dr. Gale, 

 one of the examiners of the Patent Office, has made a chemical exami- 

 nation of a portion of the basin, and finds it a very pure white cast-iron, 

 containing scarcely any foreign matter, except a little carbon and silex, 

 ingredients always present in cast-iron. Patent Office Report, 1850-51. 



IRON PAVEMENTS. 



THE use of iron plates, as a pavement for streets, has been introduced, 

 during the past year, in some parts of the city of Glasgow, Scotland, 

 with great success. The pavement consists of plates about three quar- 

 ters of an inch thick, three feet long, and eighteen inches broad. The 

 upper surface is grooved, so as to resemble in some measure the inter- 

 stices between paving-stones, only that the grooves are not in contin- 

 uous straight lines, but a sort of zig-gag, so as to prevent most effectu- 

 ally horses' feet from slipping. The plates are rabbeted on the edges, 

 the one resting on and supporting the other throughout the whole 

 series. The joints are so close that none of the material forming the 

 bed or substratum can ooze upwards, as is the case with ordinary pave- 

 ment, and which causes not only the irregularities of the surface, but 

 most of the dust and mud which disfigure the streets and annoy pas- 

 sengers. The plates are laid upon a bed of sand, with some lime inter- 

 mixed, but not sufficient to give it the coherence of concrete. The 

 surface being levelled, the plates are laid on it with great facility and 

 rapidly, and being pressed down with a wooden hammer until a solid 

 uniform bearing is attained, the operation is complete. As com- 

 pared with the best stone causewaying, there is much less noise, jolting, 

 and materially diminished friction or resistance ; while the footing for 

 the horses is fully more secure than on the best granite paving. At 

 the present price of iron, the iron pavement would cost from 7s. 6d. to 

 8s. 6d., according to thickness, per square yard ; whilst granite paving 

 costs in Glasgow from 8s. to 9s., and in London from 12s. to 14s. 6d. 

 the yard. The cost of laying and preparation will be certainly not 



