212 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



fused, at Paris, in the presence of the executive committee 

 of the National Metric Commission. This mass of the alloy 

 was intended to be run into a mould of such shape as to 

 afford, eventually, a number of new line standard meters, 

 which will all be cut from this single ingot, and it is expect- 

 ed that the surplus metal will even then be sufficient to 

 make all the required new standard weights, or kilogrammes, 

 and a number of end standard meters. The weight of this 

 great ingot was 550 pounds avoirdupois ; its length about 

 45 inches ; its breadth, 6 inches ; depth, 2f inches. The proc- 

 ess of melting was facilitated by first dividing the material 

 into small pieces; a small quantity was then melted, and to 

 it were gradually added the remaining portions, in the form 

 of long, thin bars. The heat required was obtained by means 

 of an oxyhydrogen furnace fed by six gas tubes, each about 

 one inch in diameter, and supplying the ordinary illuminat- 

 ing gas, and another set of tubes which furnished the requi- 

 site proportion of oxygen. The latter gas was made on the 

 premises and stored in a large gasometer. For obtaining a 

 sufficient blast, the power of a fifteen-horse steam-engine 

 was employed. The time actually occupied in melting the 

 entire mass of 550 pounds was one hour and three minutes, 

 of which the first forty minutes were occupied in melting 

 the first half of the material. 12 A, X., 130. 



DETECTION OF STARCH IX MILK. 



Dr. Hagar accounts for occasional discrepancies in the 

 statements of different chemists in regard to the presence of 

 starch in a sample of milk by tlie peculiar property which 

 lacteo-proteine substances possess of combining rapidly with 

 iodine, and thus decolorizing a solution of it. In conse- 

 quence, no reaction for starch is obtainable until the milk is 

 saturated to this point with the iodine, and by accident a 

 chemist may stop short of this, and fail to get the reaction 

 for starch. 13 C, February 15, 1874, 270. 



QUANTITATIVE DETERMINATION OF TANNIC ACID. 



The following method, by Terreil, is regarded as sufficient- 

 ly trustworthy for technological purposes, although some 

 other organic substances besides tannin act in a similar 

 manner. It rests upon the fact that 0.1 gramme of pure 



