IWlOl AGRICULTUEAL CHEMISTRY — AGROTECHNY. 713 



in the steam bath) to hamteu the disintegration of any hard lumps, 20 cc. 

 I'f a mixture of fuming and concentrated nitric acid (1:4, added, and the 

 llasli stoppered with a .small funnel. After standing at room temperature for 

 half a day, the flask is placetl in the steam bath and allowed to digest slowly 

 for about four days, with occasional rotation. Another 10 cc. of the acid 

 mixture is then added, and the digestion Is continued until the solution is 

 clear or contains only small quantities of resistant residue. The solution is 

 transferred in portions to a 60-cc. evaporating dish and treated with 20 cc. 

 of the Benedict reagent during evaporation to complete dryness on the steam 

 bath. 



Blanks on the reagent are given the same treatment, with the exception 

 that to prevent spattering or heating 5 cc. of a 10 per cent sucrose solution 

 is added before evaporation to dryness. After the evaporation to dryness 

 the samples and blanks are baked slowly on a gas hot plate or sand bath 

 until the material has fused. After slow cooling, about 20 cc. of hot dilute 

 hydrochloric acid is added and the dish is covered with a watch glass and 

 heated on the steam bath for 1-5 minutes. The clear solution is then filtered 

 into a 250 cc. beaker, made up to a volume of at least 100 cc, heated to 

 boiling on a hot plate, and 10 cc. of a boiling 5 per cent barium chlorid solution 

 added drop by drop from a calcivim chlorid tube. The covered solution is 

 digested on the steam bath for 2 or 3 hours, and then allowed to stand in 

 the cold for at least 48 hours, after which it can be filtered without difficulty. 



The method was checked by the modified pevoxid method of Krieble and 

 Mangum (E. S. R., 41, p. 505), which had been previously checked by the 

 official peroxid method. Removal of the silica in feeds and feces gave results 

 in the peroxid method agreeing closely with the new method, the latter 

 checking the peroxid method within an average of 3.17 and 4.17 per cent, 

 respectively, for feces and feeds. 



Estimation of small quantities of lead in foods and substances containing 

 calcium phosphate, B. W. J. Wakken (Analyst, 44 (1919), No. 519, pp. 199, 

 200). — The technique of the method, which was devised to avoid loss of lead 

 through occlusion with precipitated phosphates, is as follows : 



Ten gm. of the material is incinerated in a silica dish, dissolved in a little 

 water to which 1 cc. of nitric acid has been added, filtered, and washed. The 

 colorless filtrate is treated with a slight excess of ammonia and the precipitate 

 washed well. The precipitate, which contains pi*actically all of the lead, is 

 washed into a Nessler cylinder with water and 5 cc. of dilute acetic acid is 

 added, followed by an aqueous solution of hydrogen sulphid. The color of 

 the slightly turbid solution is matched with a standard consisting of a dilute 

 lead solution treated in a similar manner with ammonia, dilute acetic acid, 

 and finally hydrogen sulphid solution. 



The estimation of the approximate quantity of meat in sausages and meat 

 pastes, G. Stubbs and A. More (Analyst, U (1919), No. 517, pp. 125-127).— The 

 method described has been in use in the Government Laboratory (England) 

 in testing sausages imder the Meat Rationing Order, 191S, of the Ministry of 

 Food, which fixes the minimum quantity of meat in first quality and second 

 quality sausages at 67 and 50 per cent, respectively. The method is based 

 on the assumption that meat (beef, mutton, or pork) is free from carbohydrate 

 and crude cellulose matter and contains a fairly imifonii percentage of nitro- 

 gen calculated in the fat-free meat (3.75 per cent in beef and mutton and 4 

 per cent in pork), and that the substances used as fillers contain, when in 

 condition suitable for mixing, about 40 per cent of water, about 50 per cent 

 of carbohydrate and crude cellulose matter, and 1 per cent of nitrogen. 



