Polytechnic Association Proceedings. 669 



employed. A pencil connected with the levers moves across the 

 paper, varying its position with the varying force. As the paper 

 moves at the same speed to the end of the trip, every stoppage of 

 the train will be accurately indicated. One objection made to the 

 arrangement is that in going over a descending grade, or in 

 approaching a station, the dynanometer operates the same as when 

 the locomotive is at rest; thus the number of stoppages is often 

 confounded with the times when steam is shut ofl" from the cj'linder 

 while the train is in motion. 



PHOSPHATES. 



M. Collas, of France, has been long experimenting with phos- 

 phates, and particularly with phosphate of lime. He has shown 

 that the latter becomes a decomposing agent of putrefaction, and 

 after death hastens the dissolution it was the means of preventing 

 during life; it also favors the development of new existences. In 

 mothers, under certain conditions, there is a deficincy in the normal 

 quantity of phosphate of lime, owing to the amount required for 

 the development of the infant. The following preparations, recom- 

 mended by him, are reported in The London Chemical 2{ev:s: 1. 

 Solution of phosphate of soda, eight grammes in spring water, to 

 be taken at the rate of two or three glasses per day. 2. Phos- 

 phoric lemonade, consisting of two grammes of phosphoric acid in 

 a litre of spring water, taken from time to time as a beverage. 3. 

 Hydrated phosphate of lime milk; fifty grammes of ordinary 

 hydrated phosphate of lime, mixed with one hundred grammes of 

 water, in a mortar, and afterward passed through a strainer. One, 

 two, or three spoonsful to be taken daily, especially in soup. This 

 is the best way of administering phosphate of lime to rickety chil- 

 dren. The phosphate of soda has the property of converting 

 sugar into glucose in the presence of carbonic acid. 



SPIEGELEISEN. 



The important ingredient in making steel by the Bessemer pro- 

 cess, known only by the name of spiegeleisen, a German word mean- 

 ing "looking-glass iron," and suggested, probably, from the bril- 

 liant appearance of the large planes of crystalization shown on the 

 fracture of the iron, is now exciting considerable interest at the 

 Paris Exposition, where specimens of similar combinations of iron 

 and manganese from various countries may also be seen. A corre- 

 spondent of The Engineering estimates that the steel manufactures 

 of England require at present an annual supply of about ten thou- 



