REPORT OF THE CHEMIST. 203 



of aluminum from iron, upon the Kjeldahl method for determining 

 nitrogen, and upon the analysis of brines. 



It has long boon the practice of the Bureau of Chemistry to sys- 

 tematically te.^t the purity of all chemical reagents furnished to the 

 Bureau's analysts. During the past two years much difficulty has 

 been experienced in securing chemical reagents of satisfactory purity. 

 This applies not merely to so-called chemically pure reagents but 

 also to those reagents supposedly of high quality, which bear upon the 

 label an analysis purporting to represent the amounts of impurities 

 found in the reagent. In many cases these labels have been found 

 to be directly misleading. For example, peroxide of lead which, 

 according to the label, Avas supposed to contain only a trace of 

 nitrates, actually contained from 20 to 30 per cent of lead nitrate. 

 Particular difficulty has been encountered in the case of those re- 

 agents Avhich are not very soluble, such as barium carbonate. How- 

 ever, during the last few months of the year there was some improve- 

 ment in the quality of the reagents furnished. Such heavy chemi- 

 cals as the mineral acids, ammonium hydroxide and similar products 

 have usually been found to be of good quality and complying Avith 

 the specifications under which they are sold. 



CONSERVATION OF FOODSTUFFS. 



The -fleshing of poultry. — Experiments were conducted to demon- 

 strate that Avheat is not necessary or even desirable as a feed to fieshen 

 poultry. An economical ration has been found that will cause young 

 chickens to gain over 35 per cent of their initial weight in 14 davs. 



Fish.— BnWetm 378, " Fish Meal : Its Use as a Stock and Poultry 

 Food," and Bulletin 538, "Shrimp: Handling, Transportation, and 

 Uses," have been published. A paper embodying analytical data on 

 the food value of 20 common food fishes, with special reference to 

 seasonal variation, has been completed. A bulletin on the methods 

 of preserving, fish by freezing, from the season when the supply is 

 abundant to the time Avhen it is scanty, has been finished. Work on 

 the Avet as compared Avith the dry chilling and packing of fish has 

 been begun. Preliminary observations indicate that contact with 

 water or melting ice causes the fish to absorb water, to lose soluble 

 protein and to deteriorate in flavor. 



Fermentation and 'pickling. — Work on potato silage for cattle food 

 has been continued in cooperation with the Bureau of Animal In- 

 dustry. The work on the fermentation of sauerkraut has been con- 

 tinued and extended to the household preserA^ation of corn, beets, 

 and string beans, using vinegar, or soured corn-meal extract as a 

 starter, to prevent initial deleterious fermentation. The substitu- 

 tion of brining for pickling in the preservation of certain A'egetables 

 has also been examined. 



Drying., starch production. — Progress has been made in the im- 

 provement of the methods of drying apricots and peaches. The 

 Avork on the utilization of potatoes by drying and by the manufacture 

 of starch has advanced to such a stage that these processes Avill soon 

 be conducted on a commercial scale large enough to determine the 

 question of costs. The preparation of sweet-potato flour and the 



