AGRICULTURAL CHEMISTRY AGROTECHNY. 609 



Detecting potassium with tartaric acid, II. RfX'KLEBEN (Ztschr. Angcw. 

 Chcm., 26 {1913), No. 49, Aiifsatztcil, pp. 375, 376). — In discussing tlie metliod 

 proposed by Winkler (see above) it is pointed out that when the concentrations 

 are not properly controlled the potassium hydrogen tartrate is dissolved or the 

 tartaric acid remains undissolved despite the fact that the potassium ion may be 

 absent. The test also loses its force when the necessity exists for making a 

 blind test, as proposed by Winkler, with distilled water or a sodium chlorid 

 solution. For a number of years the following i)rocedure has been used, espe- 

 cially for beginners in the laboratory: 



To the solution, which should not be too dilute, is added a fairly concentrated 

 solution of sodium bitartrate. If it is desired to employ tartaric acid it should 

 be utilized as a solution of tartaric acid containing sodium acetate, and with 

 the precaution that the latter is not employed in a large excess. If no pre- 

 cipitate results on gently rubbing the walls of the vessel with a glass rod, the 

 glass rod with its adhering fluid is put on a watch glass holding a few drops of 

 a 10 nor cent solution of a potassium salt, and when crystallization lias set in 

 the glass rod with its adhering fluid is replaced in the solution to be tested. 



The author believes this method is better than the one proposed by Winkler. 



The micro-chemical detection and distribution of aluminum in the plant 

 kingdom, E. Ivkatzmann (Sit;:ber. K. Akad. Wiss. [Vicnnal, Math. Naturw. 

 Kl., 122 (.1913), I, No. 2, pp. 811-336, figs. 6).— The methods for the micro- 

 chemical detection of aluminum in plant tissues recorded in the literature were 

 •studied and Cs-SOi was the only reagent found satisfactory for detecting it as 

 Al::(S04)3.Cs2S04. The sensitiveness was 0..3 microgram. A modification of the 

 method was necessary, however, in order to be able to work more rapidly. 



One hundred and thirty plants representing various families were examined 

 for the presence of aluminum. The results indicate that aluminum is widely 

 distributed in the plant kingdom and some plants might justly be termed 

 " aluminum plants." Many cryptogams show a marked accumulation of alumina 

 iu the sporophylls, and the blossoms of angiosperms contain more aluminum 

 than the other parts of the plant. 



The clay bodies described by Radlkofer could be found only in a few varieties 

 of symplocos. It has not been definitely settled, however, that these bodies 

 consist of clay only, and they probably contain silica. When aluminum is 

 present with silica it is hard to detect, even with the Thenard blue test. 



Some plants possess a sfieciflc selective affinity for aluminum. 



The determination of the lime requirements of the soil, H. B. Hutchinson 

 and K. MacLennan {Chcm. News, 110 {191.',), No. 2854, pp. 61, 63).— The various 

 methods heretofore proposed for determining the lime requirements of soils, 

 including those of Loew and Jones, are critically discussed. A'eitch's method 

 (E. S. R., 14, p. 418) was found to give results closely corresi>onding to the 

 actual but it is claimed to be a very tedious process and difficult of adoption on 

 a large scale. " It appeared, therefore, that a closer investigation of the action 

 of certain carbonates on the soil might give a measure of prevailing acidity, 

 and would possibly conform more closely to natural conditions than some of the 

 compounds hitherto employed." 



As preliminary work with sodium carbonate and bicarbonate gave unsatis- 

 factory results, the use of calcium bicarbonate was pi-oposed. The solution is 

 prepared " by passing a current of carbon dioxid into a suspension of calcium 

 carbonate in distilled water, or by means of a ' Sparklet ' or refillable soda 

 water syphon, vrhere bulbs of compressed carbon dioxid are used. The latter 

 method is the more convenient, and permits of the preparation of a saturated 

 solution within quite a short time. A large excess of carbonate must be used 



