TWENTY-SEVEN Samples Cider Vinegar CONTAINING ADDED WATER OR ADDED SPIRIT VINEGAR SOLD IN OHIO MARKETS. (10) 95 252 4.II 2.50 0.28 24.4 4.4 4.0 8.4 8.66 3.23 97 3.84 2.35 0.30 9.8 4.4 20.2 24.6 8.11 3.70 303 In columns 1, 3, 5, and 8 of the accompanying tables, results are stated as grams per 100 grams of the sample. In column 4 are given the number of cubic centimeters of decinormal acid required to neutralize the filtered water solution of the ash derived from 100 grams of the vinegar. In columns 5 and 6 are the number of milligrams of phosphorus pentoxide (P,O,) respectively in the water solution and the water insoluble portion of the ash derived from 100 grams of the sample. Column 7 contains the sum of these two quantities, or the total phosphorus pentoxide. In column 8, what Hehner' calls "original solids” are given. These numbers are obtained by multiplying the acetic acid quantities by 1.5 and adding to this the total solids. It is assumed by Hehner that three parts of sugar by alcoholic and acetic fermentation yield two parts of acetic acid, this being approximately the theoretical quantitative relations : C,H,,O 12 6 2C,H,OH 2HC,H,O,. 120 Hence, by increasing the acetic acid in the ratio of two to three, we get approximately the theoretical quantity of sugar from which it was produced. By adding to this the amount of solids still remaining in the vinegar, the quantity of solids present in the unfermented liquid is assumed to be obtained. Of course such an assumption is extremely far from the truth, because, from various losses during fermentation, by volatilization of alcohol and acetic acid, only one-half to three-quarters of the theoretical yield of acid is obtained, and this loss varies greatly in the different processes, and in the same process depends largely upon individual care during each of its steps. Further, during the fermenting and settling periods albuminoid and other constituents settle in considerable quantities, so that such calculations possess little real worth, and, when spirit vinegar is used as an adulterant of cider or malt vinegar, they may become decidedly misleading. The figures in columns 8, 9, and 10 are given principally for the sake of comparison with previous analyses which have been reported in this way. In column 9 the percentages of ash to "original solids," found in column 8, have been given, obtained by dividing 100 times the 1 Analyst, 16, 82. per cent. of ash as given in column 3 by the per cent. of "original solids." In the same way the milligrams of total phosphorus pentoxide per 100 grams of original solids are reported in col umn 10. Of these results, the quantity of ash, the alkalinity of the ash, and amount of soluble phosphates are of considerable uniformity in pure cider vinegar, and these, when considered with the other characteristics above enumerated, serve to differentiate this kind quite sharply from all other commercial varieties and to afford a basis for the approximate estimation of the quantity of spirit vinegar or of water, with which pure cider vinegar may have been adulterated. [CONTRIBUTION FROM THE LABORATORY OF AGRICULTURAL CHEMISTRY, OHIO STATE UNIVERSITY.] ROOT TUBERCLES IN WATER CULTURE.' BY H. A. WEBER. Received November 22, 1897. INCE the discovery by Hellriegel of the connection between root tubercles and the fixation of atmospheric nitrogen by leguminous plants, the literature on this interesting and important question is being constantly enriched by painstaking experiments on the part of scientific investigators all over the world. The subject has thus far been studied only in connection with sterilized soil or sand. It occurred to the writer that it might be possible to produce root tubercles in water culture and thus be able to observe the process better than when the roots of the plants were buried in soil or sand. The work of conducting the experiments about to be described was entrusted to Mr. J. C. Britton, one of the writer's advanced students. The results more than met my expectations, and this preliminary notice is made public for the benefit of those who may feel inclined to employ the method in their investigations. For the past four or five years the writer has employed in water-culture experiments an apparatus designed by himself, which presents certain advantages over the methods heretofore described. As this apparatus was employed in the experiments 1 Read before the Columbus Section of the American Chemical Society, Nov. 10, 1897. under consideration, a brief description of the same may not be out of place. As will be seen from the accompanying illustration, a is an aspirator of four liters capacity; b, and b, are ordinary salt mouth bottles of two liters capacity, which serve as culture jars ; c is a small flask with a side tube, as used in fractional distilla tion; d is a collecting bottle of four liters capacity. The culture jars are fitted with cork disks to hold the plants in the usual manner and also support the thistle tube and the siphons as shown in the illustration. At the beginning of a vegetation experiment, the flask c, the culture jars, and the aspirator, are filled with the nutrient solu The aspirator is closed with a rubber stopper carrying a glass tube, to the end of which a short piece of rubber tubing is attached. In this manner the solution is conveyed to the thistle tube, which extends to near the bottom of jar b,, the flow being controlled by means of a Hoffman clamp placed on the rubber tubing. By means of a siphon, the short arm of which extends a short distance below the surface of the solution in jar b,, and the long arm nearly to the bottom of jar b,, the solution flows into jar b. Another siphon with one arm extending a short distance below the surface of the solution in jar b,, and the other below the side tube in flask c, carries the solution into flask c, from which it runs through the side tube into the collecting bottle. The drop of the solution into the thistle tube is so regulated that the aspirator will empty itself in about twenty-four hours, when the solution in the collecting bottle is transferred back into the aspirator. This is done once a day until the vegetation experiment is completed. The advantages of this arrangement are: 1. Two seedlings, or if, as the writer has frequently done, another culture jar be inserted between jar b, and the flask c, three seedlings can be grown in the same solution at the same time, so that, if an accident should happen to one of the seedlings, the experiment need not necessarily fail. 2. The solution is continually being aerated as it drops into the thistle tube and into the collecting bottle, as well as when it is transferred to the aspirator. By this means the roots of the seedlings are constantly supplied with free oxygen, a condition necessary for healthy growth. 3. Plants can be grown to maturity without removing them to other jars filled with fresh solutions. 4. The solution in the culture jars always remains at the same level, i. e., on a level with the side tube of the flask. Two solutions were prepared as follows: 1. COMPLETE NUTRIENT SOLUTION (Wolff's Solution). The whole dissolved in distilled water, neutralized with sodium carbonate, and diluted to one liter. 2. COMPLETE NUTRIENT SOLUTION WITHOUT NITROGEN. The whole dissolved in distilled water, neutralized with sodium carbonate, and diluted to one liter. For the growing of plants |