122 



CHEMISTRY. 



the siimiltaneous presence of concentrated sulphuric 

 acid, a nitrite, and a cuprous compound. The au- 

 thor suggests that it may serve for the recognition 

 of the nitrites. 



For the detection of vegetable oils in lard, Ferdi- 

 nand Jean finds that these oils, if added to lard, 

 etc.. increase the density, raise the iodine figure, 

 lower the melting point, the standard of fatty 

 acids, and Hoerstoffer's number, and diminish the 

 optical deviation. With the oleo-re'ractometsr 

 all the vegetable oils reflect to the right hand of 

 zero ; hence lards mixed with vegetable oil show a 

 deviation less than 12'5, the normal deviation of 

 pure lard. The animal fats change the density 

 little, but lower the iodine figure, raise the melting 

 point and the standard of the fatty acid, increase 

 KosM-stoffer's number and the optical deviation of 

 the oleo-refractometer beyond 12'5. 



The principle of the variation of the velocity of 

 sound in a gas with its density is utilized in new 

 apparatus by Mr. E. Hardy for the detection and 

 estimation of small amounts of marsh gas in the 

 air of mines, etc. The air under examination is 

 forced through a small organ pipe, and the note 

 thus produced is compared with that given out by 

 a second pipe fed under parallel conditions with 

 pure air. The apparatus being so arranged that 

 the moisture, carbonic acid, and possible variations 

 of temperature exert no influence on the result, the 

 number of beats per second produced gives a meas- 

 ure of the methane present. 



E. Merck has found, on experiment, that even 

 minimum, traces of alcohol can be detected in 

 aqueous solutions by his special molybdic acid 

 (pure). The sensitiveness of the test extends for 

 ethylic alcohol to 0-02 per cent., and for methyl al- 

 cohol to 0'2 per cent. 



Agricultural Chemistry. Although it is at 

 temperatures exceeding 100 C. that the oxygen of 

 the air burns rapidly the organic matter of the soil, 

 oxidation is fairly active between 40 and 60 C. 

 We can thus understand, say P. P. Deherian and E. 

 Bemoussy, how in hot regions lands plowed but 

 left without manure become barren by the disap- 

 pearance of the humus which the spontaneous veg- 

 etation had accumulated. In our cool regions this 

 disappearance is slower. Still the fields of the ex- 

 perimental farm of Grrignon, France, bearing va- 

 rious crops and left without manure, lose in ten 

 years half of their organic matter. If the soil is 

 plentifully manured the oxidation is, in the opinion 

 of the authors, too slow, whence the incessant work 

 the farmers have to undertake to allow the oxygen 

 to enter into the soil and bring the humus into such 

 a state that nitrification can be effected. The ancient 

 practice of allowing ground to lie a year fallow after 

 three years' cultivation is shown, according to De- 

 heran, to have rested upon a sound basis, for the 

 land gains considerably in nitric nitrogen during 

 the fallow year. With modern manures the neces- 

 sity for this no longer exists, although the practice 

 st ill survives in many places. 



The results obtained by the investigations of a 

 committee of the British Association on the con- 

 stituents of barley straw make it appear probable 

 that the fiirfuroid constituents of the cereals are 

 not. a-; has hitherto been supposed, secondary prod- 

 ucts of assimilation, but are directly buil!: up by 

 the plant. The furfuroids appear to form a very 

 lar<;e group, comprising a number of substances 

 which differ in their susceptibility to yeast, and 

 yirld oxn/.oncs of different melting points. The 

 1 planN are distinguished by the amount of 

 grain which they produce, the amount being no 

 'hau 40 per cent, of the weight of the entire 

 plant. It , .liable that during the period 



of production of seed part of the necessary mate- 



rial is derived from the tissues of the stem and 

 leaves. 



The chemical relations of the soil to surface wash- 

 ing are discussed in a bulletin of the United States 

 Department of Agriculture on " Washed Soils : How 

 to Prevent and Reclaim them." It has been re- 

 peatedly shown, the bulletin says, " by experiments 

 and by the experiences of farmers that a soil, as a 

 rule, absorbs water more readily as the content of 

 organic matter and humus increases. Surface 

 erosion can therefore be largely prevented by such 

 a system of cultivation and cropping as will intro- 

 duce as large a quantity of organic matter into the 

 soil as possible." Straw, leaves, and other vegetable 

 refuse, when used to stop washing of the soil, act 

 in a double capacity : first, in a mechanical way, 

 and ultimately by supplying, through their decom- 

 position, organic matter. " The most important 

 thing in the recovery of waste fields is the incor- 

 poration of organic matter of some kind in the soil : 

 pea vines, stubble, osiers, or leaves from the forest may 

 be used as a source of the organic matter. The straw 

 from one acre of land which has been recovered . . . 

 will be sufficient to start the recovery of another 

 acre, even if this be furrowed with gullies. When 

 enough organic matter can be used as a surface 

 dressing, this layer helps greatly to retain water 

 and to make the underlying soil more absorbent. 

 As soon as a sufficient supply of humus has been 

 accumulated and the lands are brought up to an 

 adequate degree of fertility, clover or grass should 

 be seeded ... or rye, oats, or field peas should be 

 sown to help hold the surfaces. Little by little, but 

 more rapidly than would be expected from the for- 

 bidding aspect of the field, the land can be reclaimed 

 again and made productive through the accumu- 

 lation of humus and organic matter." A soil which 

 contains a fair supply of lime is also much less 

 liable to wash than one similarly situated and ex- 

 posed which is deficient in lime. This is because 

 clays deficient in lime when brought into suspen- 

 sion by moving waters, will remain in suspension 

 and keep the water turbid for a long time ; while if 

 they are heavily impregnated with lime salts, they 

 form flocculent masses which soon settle. This 

 fact has been established by the investigations of 

 Schulze, Schloesing, and Ililgard. A change in the 

 physical condition of the soil is also brought about 

 by the incorporation of lime, whereby it is made 

 more permeable. A number of the ordinary ferti- 

 lizing materials have an important effect upon the 

 texture of soils, but few systematic investigations 

 of the subject are recorded. 



In studying the effect of acidity on the devel- 

 opment of the nitrifying organisms of soils, E. E. 

 Ewell and H. W. Wiley used as an acid medium a 

 solution containing ammonium sulphate, dipotas- 

 sium hydrogen phosphate, magnesium sulphate, 

 and calcium chloride, with which 22 virgin and 22 

 cultivated soils, coming from 22 States and Territo- 

 ries, were tested for two months. One hundred 

 cubic centimetres of this solution were used for 

 each test. The average result 'of the 44 tests was 

 28 parts per million of nitrogen were nitrified, or, 

 excluding 5 cases in which no nitrification oc- 

 curred and 5 cases in which it was 40 parts per 

 million or more, of 34 tests, 20 parts per million. 

 It appeared that nitrification stopped after the 

 formation of an acidity equal to from 3 to 4 cubic 

 centimetres normal alkali, or when the reaction 

 reached 54- to 6^ of Mr. Fuller's scale. In the case 

 of 2 peaty soils from the muck lands of Florida, 

 the results were 20 and 22 parts of nitrogen nitrified 

 per million, which are very close approximations to 

 the mean result of all the tests. The soils giving 

 the most excessive results (130 and 170 parts per 

 million) were from Alabama, and examination 



