202 ANNUAL OF SCIENTIFIC DISCOVERY. 



mation and mixing of pulverulent matter, while in the jelly or paste 

 state, coal-tar, wood-tar, or petroleum, pitch, or rosin, is added to 

 correct fetid effluvia, in case any should be evolved during the opera- 

 tion. When no actual putridity exists in the organic matter to be 

 converted into manure, quicklime, or lime that has been used in puri- 

 fying coal-gas, is sometimes used to effect the desiccation of such 

 materials, and the mass is then formed into bricks or dumplings, for 

 the purpose of convenience of transportation, and these may be pul- 

 verized or broken into fragments, for the purpose of distribution over 

 the soil. But whenever putrefaction has commenced, the lime cannot 

 be used, as by abstracting water it would cause the evolution of am- 

 monia, and great loss of material would be sustained. Patent Office 

 Report, 1849. 



HUMUS AND THE PART PERFORMED BY MANURES IN THE NOUR- 

 ISHMENT OF PLANTS. 



IN the Journal de Pharmacie for July, M. Soubeiran publishes an 

 important paper on the chemical analysis of humus, and on the part 

 performed by manures in the nourishment of plants. The following 

 is an abstract of the results obtained by him : 1 . Ligneous tissue de- 

 composed by contact with humid air changes into humus, and forms 

 at the same time carbonic acid which can be absorbed by the roots of 

 plants. 2. The proportion of carbon in the humus of mould and 

 manure never exceeds 56 or 57 per cent. This is the extreme limit 

 obtained by the decomposition of ligneous tissue in contact with air 

 and humidity. 3. Pure humus contains 2k per cent, of nitrogen, 

 which appears essential to its composition. 4. Humus is but little 

 alterable by the action of the air. 5. Humus, which is but sparingly 

 soluble in water alone, acquires solubility by combining with lime ; 

 but the principal agent of its solution is carbonate of ammonia, which 

 reacts equally on free humus and on humus engaged in a calcareous 

 combination. 6. Humus, rendered soluble, is absorbed by the roots of 

 plants. It assists directly in the nourishment of vegetables. 7. More- 

 over, humus exerts a favorable action on vegetation, by attracting and 

 retaining the humidity of the air and ammonia, by facilitating the so- 

 lution of phosphate of lime, by ameliorating the physical qualities of 

 the soil, and by moderating and regulating the decomposition of putre- 

 fiable animal matters. 8. Turf, modified by the contact of air, lime, 

 and alkaline substances, has all the characters and properties of mould. 

 It is extremely favorable to vegetation, after the addition of saline 

 matters, alkaline and earthy chlorides, sulphates, and phosphates, in 

 which it is habitually wanting. 9. The best manure is that which 

 contains at once earthy and alkaline salts, ammoniacal salts, putrefia- 

 ble animal matter, ready-formed humus, and vegetable refuse in the 

 course of transformation. 10. In the appreciation of a manure, we 

 should take into account, not only the proportion of nitrogen furnished 

 by analysis, but also the state in which this nitrogen exists in the 

 manure ; that is to say, in the state of an ammoniacal salt or of putre- 

 fiable animal matter, in the state of soluble ammoniacal salt or of 



