138 



tufa, (commonly called marl in the West,) was forwarcled to the laboro-- 

 toiy by S. W. Itandall, of Jolict, Illinois, and wc subjoin its analysis 

 because such deposits are quite common in the calcareous and drilt 

 regions of the Northwest. 



Carbonate of lime 81.43 



Sulphate of lime 4,21 



Earthy matter, insokible in hydrochloric acid 12.02 



Water, determined at 100^ C 2.31 



100.00 



]\Iixed with muck or barn-yard manure, this substance will have the 

 effect of mikl lime. Where fuel is cheap it may l)e made more active 

 by burning- it as lime is burned. 



Sulphur in ^iun^eeal coal— Onio lhiesiiones. — Professor Worm- 

 ley, in a i)aper appended to the Ohio Geological Report for 1870, gives 

 an interesting account of the chemical composition of the mineral coals 

 and limestones of that State. Without any very accurate determination 

 of the fact, it has heretofore been assumed that tlie sulphur in bitumin- 

 ous coals exists in combination with iron in the form of lerrous sulphide, 

 but the investigations of Professor Wormley prove conclnsively that 

 this is not the case, at least so far as the coals of Ohio are concerned. 

 In all his investigations a large redundancy of sulphur over the quantity 

 of iron necessary to'convert it into a sulphide was found. The experi- 

 ments detailed on the heating properties of different coals are very 

 interesting. Science can hardly do a more important service, at the 

 in-esent time, than to determine how much heat can be produced by the 

 combustion of a given weight of coal of the various qualities. This 

 paper reports that all the limestones of Ohio contain magnesia, though 

 in very difrereut proportions. The blue limestone (Trenton) has o x'er 

 cent;, the Clinton 12, the Corniferous 28, and the Niagara 35. These 

 facts are important in an agricultural point of view, but we regret that 

 the ijrofessor did not determine the proportion of phosphate of lime in 

 these several qualities of stone. The permanent' action of lime as a 

 manure depends much on the quantity of phosphoric acid it may contaiti. 



Artificial water-leme. — It has been long known to chemists that 

 Vv-ater-lime consists substantially of quick-lime, burnt clay, and a small 

 portion of the oxides of iron and magnesia, but scarcely any effort has 

 been made to utilize this knowledge. All yellow or red clays contain 

 iron, and most specimens of lime in use contain the required magnesia. 

 If burnt clay or brick-dust in line powder be mixed with an equal weight 

 of fresh slaked lime and twice this weight of clean, sharp sand be added, 

 a compound will be formed which will harden nnder water equal to the 

 best hydraulic cement. 



Germination — its relation to light. — The theory of the germi- 

 nation of plants, which has been heretofore admitted, requires that the 

 germinating seed -be excluded from direct sun-light. Late experiments 

 ■ appear to establish the fact that, while exclusion from the luminous 

 rays of the solar spectrum is necessary to the healthy germination of 

 seeds, yet the chemical or actinic rays are indispensable to that process. 

 These penetrate mueh deeper into the soil than do the luminous rays. 

 The exclusion of the chemical rays, and not the absence of oxygen alone, 

 is assumed to be the cause of seeds failing to grow when buried too 

 deeply in the earth. Will our agricultural colleges settle t'lis question 



I 



