48 ANNUAL OF SCIENTIFIC DISCOVERY. 



15 inches in length ; the one had a flat surface, and the other two corru- 

 gated arches. The arch with the flat surface gave way under a weight 

 of a few pounds, while the corrugated arch withstood the weight of two 

 men, who violently surged upon it, without making the least impres- 

 sion. In another experiment, made upon a larger scale, and under 

 equal conditions, the plain arch gave way with 3,126 Ibs. of pig iron 

 upon its crown, while the corrugated arch bore the weight of 16,094 

 Ibs. of the same metal for 48 hours, without the least perceptible 

 deflection. This was afterwards increased to 27,000 Ibs., which also 

 remained for 48 hours, without the least deflection perceptible to the 

 eye. 



IRON-WORKS AMONG THE HOTTENTOTS IN 1849. 



THE Bakatlas work a great deal in iron. The ore is smelted in cru- 

 cibles, a great deal of the metal being wasted, and only the best and 

 purest preserved. They use a sort of double bellows, consisting of two 

 bags of skin, by which the air is forced through the long tapering 

 tubes of the two horns of the oryx. The person using the bellows 

 squats between the two bags. Their hammer and anvil consist of two 

 stones. They, nevertheless, contrive to turn very neat workmanship 

 out of their hands, such as spears, battle-axes, assagais, knives, sewing- 

 needles, &c. Cumming's South Africa. 



WROUGHT-IRON RAILROAD CARS. 



THE Railroad Journal states that a company has been recently 

 formed for the purpose of manufacturing wrought-iron railroad cars. 

 The sides, roof and bottom of the car are made of wrought boiler and 

 Russia Iron thus presenting what may truly be termed a Safety Car. 

 No broken axle, bar, tie or rail can pierce the floor, and, in case of a 

 collision, the frame may become dented, but cannot break up into dan- 

 gerous splinters. These cars are not only rendered more durable than 

 the ordinary wooden car now in use, but they are a lighter article, 

 lower in price, and are perfectly fire and weather proof. They may be 

 rendered highly ornamental also. 



METALLIC CASKS. 



MR. R. CLARE, of Liverpool, has, within the year, patented a plan 

 for the manufacture of metallic casks. The invention consists in 

 making casks from staves made of sheet metal, the object being to 

 render them conveniently portable when not required for use. The 

 staves are formed with the requisite bulge and taper to produce a cask 

 of the desired form, and are provided with flanges at the edges for 

 securing them to each other, which may be d8ne by bolts and nuts, 

 or any other convenient method. The hoops may be made of wood or 

 of iron, being provided in the latter case with a screw to tighten them. 

 The heads of the casks may be formed of wood or metal, and retained 

 in their places between knees of angle iron. When the casks are 

 employed for containing fluids, it is recommended to introduce a slip 

 of India rubber between the abutting flanges of the staves. 



