Processes in the Useful Arts. 833 



resting to preserve an account of it, I send you the measurements which 

 we took. 



The Winch Bridge is formed of two chains, composed of links six inches 

 in length, the iron of which is 14 inch in circumference. The floor, which 

 is laid on the chains, is eighteen inches wide, and has a hand-rail on each 

 side. The chains are fixed by bolts into the rocks at each end. The 

 lengths of the chains are as follow : — 



Feet. Inches. * -th 



Length of chain between the rocks, - 59 4 



■ supported by the rock on N. side, 12 



■ — — — s. side, 



not visible, being covered with rubbish. 

 The centre of the bridge, which is about three feet lower than the ends, 

 was, on the 2d July 1828, twenty-one feet above the level of the water, the 

 depth of which was 8| feet. This measure is very different from that given 

 in all the printed accounts of it I have seen, which vary in making it from 

 fifty to sixty feet high. 



The bridge, which is in a decayed state, and not pleasant to pass over, 

 is steadied by two chains, which are passed round the floor, and fixed in 

 the basalt rocks on the west side. 



2. On Lithochrcmy, or the Art of multiplying Oil Coloured Lithographic 



Paintings. 

 The art of lithography, in which designs are executed with one tint, 

 has been carried to great perfection. In Germany, M. Boisseree has long 

 ago succeeded, by the successive application of several plates, to give to 

 lithographic drawings executed under his direction by M. Strixner, all the 

 effect of a design coloured with several tints. More recently, however, M. 

 Malapeau has attempted to obtain oil pictures by means of the mechanical 

 process used in lithography. After painting on the stone the general de- 

 signs, no fewer than twenty-seven rollers are then in succession passed over 

 the stone in order to communicate to it all the colours which enter into the 

 picture. An impression is then taken in the usual manner, and of course 

 this impression will be a picture coloured with the twenty-seven tints 

 which have been employed. This art is most perfect when the painting 

 is on a large scale. M. Malapeau has executed a Christ larger than life, 

 the effect of which is said to be surprising. — See the Revue Encyclopedique t 

 June 1828, p. 818. 



3. On the Grass Oil of Nemaur. By J. Forsyth, Esq. From the 

 Calcutta Transactions, vol. iii. p. 213. 



The grass oil of Nemaur (Roosaka Tel,) is in high repute among the 

 natives of India as a specific for rheumatism. The method of using it is 

 by rubbing about two drachms of the undiluted oil over the pained part 

 in the heat of the sun, or before a fire twice a day. It causes a strong 

 sense of heat and pricking, which usually lasts for two hours or longer. 

 The grass is met with in frequent distinct patches, in the jungle through- 



VOL. IX. NO. II. OCTOBER 1828. Y 



