314 Progress of Invention. 



soda, instead of eight per cent, sulphuric acid is used. And if, 

 after the potatoes have been macerated in the solution of soda, they 

 are boiled in a solution containing nineteen per cent, soda, a sub- 

 stance resembling stags horn, and which may be used for knife 

 handles, etc., will be formed. Turnips may be used instead of 

 potatoes in the production of the artificial horn ; and if carrots are 

 substituted for the potatoes, a very excellent artificial coral will be 

 obtained. 



Railway Safety Switch. — It is of the utmost importance that 

 the points on railways should be in the proper position. If they are 

 not, a train may run on the wrong line, and thus destructive col- 

 lisions ensue. Such has been but too often the cause of serious 

 accidents, and great mischief to both life and property. The 

 pointsman may be neglectful, or over- fatigue may cause him to 

 forget his duty. Hitherto there were no effective means of dis- 

 covering the circumstance until it was too late. A very ingenious 

 and simple application of electricity now renders it extremely easy. 

 The switch is so arranged that, whenever it is not in a proper 

 position, it completes the electric circuit of a galvanic battery, and 

 the current thus set in motion operates on an electro-magnetic 

 apparatus, which keeps an alarm bell ringing where it cannot but 

 draw the attention of responsible persons to the pointsman's neglect, 

 so that the switch maybe put in its proper position before any injury 

 is done. 



Manufacture of Starch. — An improvement of considerable im- 

 portance has recently been made in the manufacture of starch. It 

 is founded on the fact that, although the specific gravities of the 

 starch and of the substances associated with it in the grain, etc., 

 from which it is extracted are very nearly, they are not quite the 

 same; and the improvements, which is due to M. L. Maighe, consists 

 in an ingenious application of centrifugal force. Water is added 

 to the crude starch in the proportion of two parts of the former to 

 one of the latter, and the mixture is introduced into a copper drum 

 which is capable of making some hundreds of revolutions per 

 minute. As soon as the proper velocity has been reached, the 

 starch, having a greater specific gravity than the water, and there- 

 fore being more affected by centrifugal force, is driven with such 

 violence against the circumference of the drum that it forms a solid 

 mass of great whiteness and purity, being entirely separated from 

 the other substances, which remain suspended in the water. This 

 method of obtaining pure starch has peculiar advantages : it re- 

 quires only a few minutes, while the ordinary process takes several 

 weeks ; it is more economical, since with it the yield is twenty per 

 cent, greater, and hence starch may be profitably manufactured 

 from other matters besides wheat, which from its nutritious quali- 

 ties should be as far as possible kept for food ; and, finally the 

 cellular tissue, gluten, etc., which are very valuable, but by the 

 ordinary modes of manufacture almost entirely go to waste, may be 

 utilized. It is not improbable that a similar application of centri- 

 iugal force might be advantageously applied to the separation of 

 other substances differing but little in specific gravity. 



