We had the pleasure, yesterday morning ot examining, at the works of Messrs. Lorenz & Sterling, an exceedingly ingenious double machine for making railway chairs, recently patented by Mr. Robert Griffiths, of Newport, Kentucky. Simple as what are technically termed chairs tor the reception of the rails appear to be, they have, nevertheless, hitherto required great labor iu the construction ; and when made, they were liable to many defects, which are all removed by the use of the machine in question. The eminent firm, who purchased the patent right for Allegheny county from Mr. Griffiths, found that, by the old mode, the process of making them was a tedious and expensive one, involving a great deal of trouble and labor; and, learning that Mr. Griffiths had invented a new machine for the purpose of forming chairs, which obviated all the former difficulties, they purchased the right to use it; Mr. G., fwho is now in this city, has superintended the construction of a machine, at present in operation, to the merits oi which too high praise cannot be awarded. The double machine will turn out, at a moderate rate of speed, the enormous quantity of four thousand chairs, or fourteen tons per day, and if required, the quantity can be increased to five or six thowand. Eight men will attend to it in all its departments, whereas, by the old machines, thirty two would be required. The quantity of coal consumed in the furnace is, besides, not half as much as before. Another great advantage which it has over all others, is that it will work on a plate of any size, since it is so arranged that) by the simple movement! of a lew screws, the bed, into which the rough plate of wrought iron i" put, can be either enlarged or contracted.— The lips too, by a similar arrangement of screws, are bent to any required angle, and the whole operation is performed with mathematical precision, thus causing the chair to fit the rail accurately, and requiring none of the hammering, which has hitherto caused so great an expenditure of labor, on our railroads. These advantages must be obvious to all, for not only are the track layers of a railroad saved a great deal of trouble, but the rails, when placed in the chairs, unite together firmly, and form a straight line, thus removing a fruitful cause of accidents, besides saving a great deal of wear and tear on the rails. We congratulate Messrs. Lorenz & Sterling on the addition they have made to their ex-iensive works.—[Pittsburgh Com. Jour.