Among new inventions for the ornamentation of glass, should be mentioned the process of “threading,” that is, the surrounding and partial covering of a body of glass of one colour with a continuous thread of glass of another colour, by which many beautiful effects of varying and toned colour are produced. Recent years have also seen the revival of what is termed cameo cutting on glass. A body of glass being formed of layers of different colours, the outer layer or layers are partially removed by eating away by hydrofluoric acid, and the remaining portions are then wrought into designs with the chisel or graver. A reproduction of the Portland Vase is one of the most remarkable specimens of this revived art, which offers excellent opportunity for the combination of lustrous colours of varied hue with delicate and exquisite ornamentation. Marked progress has been made in the production of coloured glass, formerly almost a monopoly of the Bohemian makers. =Hinges of Wrought Iron.=--[F. E. MARTINEAU.]--(B. 610.) Material consumed at time of British Association Meeting, in 1849, was about 700 tons; in 1865, about 2,500 tons, and this year, 1886, about 3,500 tons per annum. In 1865, about 300 people were employed in the trade, there are now about 380. Strip steel has to a certain extent replaced strip iron in the manufacture. =Hydraulic Machinery.=--[MESSRS. TANGYE.]--(B. 647.) The Cornwall Works have rapidly extended, now occupying six times the area covered in 1865. 2,000 men are employed. In addition to hydraulic machinery, steam engines, machine tools, machinery for gas works, patent retort lids, gas stoking and charging machines, gas engines of a novel and economical type, steam boilers of all kinds, and fixed and portable steam cranes are manufactured. These works will now turn out per month 200 steam pumping engines, 40 steam boilers, 100 steam engines used for other purposes than pumping, 800 cranes, crabs, and lifting apparatus. 300 hydraulic presses, lifts, and jacks. 5,000 complete sets of pulley blocks, and 1,000 gas retort mouth-pieces and lids.