AGRICULTUEAL CHEMISTEY AGKOTECHNY. 209 



"The details of tlie pi'ocedure adopted are as follows: Three gm. of red oak 

 SMwdust, previously dried at 110° C, is treated with 1 cc. of zinc chlorid 

 solution equivalent to 0.035 gm. of metallic zinc and dried at 110°. The saw- 

 dust is then mixed with 35 gm. of sodium peroxid and fired in the bomb. After 

 the explosion the bomb is cooled in water, and distilled water added through 

 the plug. The contents are dissolved by heating on a water bath. The solution 

 is then transferred to a beaker, acidified with concentrated hydrochloric acid, 

 and boiled for a few minutes. Two gm. of citric acid, 10 cc. concentrated nitric 

 acid, and 5 cc. of 8 per cent ferric chlorid solution are added. The solution 

 is then made alkaline and 2 cc. excess of concentrated ammonium hydroxid is 

 added. After dilution to 400 cc, the solution is titrated at 80° with potassium 

 ferrocyanid. An outside indicator of equal parts of glacial acetic acid and 

 glycerin is used. 



" The potassium ferrocyanid solution is made by dissolving 5 gm. of the salt 

 in 1 liter of water and is standardized against the zinc chlorid solution under 

 the same conditions as exist in the charge. A blank is also run on 3 gm. of the 

 untreated wood and subtracted from each determination. It is necessary to 

 keep the conditions the same throughout the titration. An excess of ammonia 

 is necessary to keep the solution from turning blue, but a large excess prolongs 

 the end point. The time required for a determination is about 25 minutes. The 

 accuracy of this method is shown by a set of six consecutive determinations." 



Apple sirup and concentrated cider: New products for utilizing' surplus 

 and cull apples, H. C. Coke (C7. S. Dept. Agr. Yearbook J9U, pp. 227-2U, 

 figs. 2). — The first part of this paper gives directions for preparing apple sirup, 

 from cull and other apples too small for retail sale, for home use on the farm 

 and on a commercial scale. Essentially the process consists in treating the 

 expressed apple juice with milk or carbonate of lime (the latter is preferred 

 for sirup making in the home) for the purpose of removing malic acid, and after 

 clarification condensing to the proper concentration. In the commercial manu- 

 facture of sirup, especially as a by-product of a steam cider mill, the juice after 

 neutralizing is treated with finely bolted infusorial earth (17.5 lbs. to 100 gals, 

 of neutralized juice) and filtered through a filter press. The filtered juice 

 is then evajiorated to the proper consistency. 



The cost of making sirup on a commercial scale as nearly as can be deter- 

 mined is probably slightly greater than making sirup from cane or sorghum. 

 The cost of sirup exclusive of investment and depreciation charges, and of 

 fuel and labor, which vary in different localities, is about 45 cts. per gallon. 

 The malate of lime may eventually be sold to chemical firms preparing malic 

 acid. 



Some recipes for cooking and candy making developed in the Office of Nutri- 

 tion Investigations are included. 



The second part of the paper deals with the concentration of sweet cider by 

 freezing as a fall activity for ice and cold-storage plants in apple sections. In 

 experiments on a commercial scale in concentrating apple juice by artificial 

 freezing during the apple-bearing seasons of 1913 and 1914, in connection with 

 a cider mill located near a commercial ice-making plant in the apple-growing 

 regions of Oregon, it was found that 5 gal. of apple juice could be reduced to 

 1 gal. of sirupy cider concentrate. " It was found that while the concentrated 

 cider would not keep indefinitely under household conditions, its larger per- 

 centage of sugars and acids kept it from fermenting as quickly as ordinary 

 cider. When kept cool, as in a household refrigerator, concentrated cider, it 

 was found, would not six)il for manj' weeks. When kept at or below 32°' F. in 

 cold storage it was found that concentrated cider could be kei^t from one season 



