Processes in the Useful Arts. 335 



Shake the alkaline solution with the oil, then heat it slightly in order to se- 

 parate the elaine from the soap of stearine. After it is passed through a cloth, 

 the elaine is separated from the alkaline solution by decantation. — Ann. de 

 Ghim. 



3. On the Steam Navigation of India. 

 In a former Number (No. vi. p. 377) we gave an account of the 

 Enterprize, the first steam-vessel which sailed to India. This vessel 

 was purchased by the Government, and seems to have given a power- 

 ful impulse to steam navigation in that part of the globe. " Besides 

 this vessel (says a writer in the Col. Press Gazette of June 9,) which 

 is employed between Calcutta and Rangoon, we have the Diana in Ran- 

 goon river, and the Comet, one of the two small vessels here of twenty- 

 four horse power, fitted up as packets, to carry passengers up and down the 

 river. Two other vessels of this description will be soon ready, and both 

 of them, by their light draught of water, are admirably fitted for carrying 

 passengers to the upper provinces during the rains, when the rivers are full. 

 Besides these vessels, which we owe to private enterprize, two armed steam- 

 vessels of Government will be ready in August. Singapore too will soon boast 

 of a steam- vessel from the Cape, and there can be no <3oubt that each of the 

 Residences will have one or two in the service of the Company. For these 

 purposes deposits of coals are about to be provided at Madras, Ceylon, and 

 Penang. There is another vessel wrought by steam (we presume a dredg- 

 ing-machine) which is now in progress, for clearing away the obstruction 

 to the navigation of the small rivers which communicate with the Hoogly. 

 By this vessel it is hoped that a water communication with the upper pro- 

 vinces may be kept open at all seasons of the year, and a journey to the most 

 distant situations, which now occupies four months, may perhaps be per- 

 formed in as many weeks. 



4. On the Bursting of Steam- Boilers. By John Taylor, Esq. F. R. S. 



In the last number of the Philosophical Magazine, this important subject 

 has been treated with great ability by Mr Taylor, whose theoretical and 

 practical knowledge must give great weight to his opinions. 



Mr Taylor begins by stating, that the most fatal and distressing accidents 

 have arisen from the bursting of one sort of boiler. This boiler consists of 

 two tubes, an inner one from three to four feet in diameter, and an outer 

 one from five feet and a half to six feet and a half or seven feet in diameter. 

 These tubes are generally made of wrought iron or rolled plates, the inner 

 one being half an inch thick, and the outer one three-eighths. The ends 

 of the boiler fix the tubes together, so that the interior tube is open at both 

 ends, at one of which is placed the fire grate, and at the other the smoke 

 and flame escape, and are conveyed to the stack or chimney most common- 

 ly by flues passing under and along the ends of the outer tube. These boil- 

 ers are usually from twenty to thirty-five feet long. 



In boilers of this kind no fewer than four accidents have happened. They 

 were mostly new, and were each furnished with a safety valve and gauge- 

 cocks. Theirs* of these was in Wheal Fortune, the boiler alone being in- 

 jured. The second, which happened at Polgoath tin-mine, was remarkable 



