No. 151.] 495 



Dr. Underbill — The silex in soils is chemically dissolved by potash. 

 The union of the two, form silicate of potash; very important to 

 the growth of plants. 



Dr. Field — Some time ago, I examined some muck in which I did 

 not discover the presence of any lime. 



Chairman — The most essential ingredient in soil is calcareous earth j 

 no plant prospers without it. 



Mr. Fleet — I think that coal ashes are useful mechanically. Mr. 

 Colman recently remarked, that large tracts of land in Russia, in 

 •which the least possible trace of lime is present, are nevertheless fer- 

 tile. That those tracts, after resting two or three years, are found 

 again restored to their fertility. Tn Lincolnshire, England, where 

 the soil is three inches deep and lying on chalk, much is found to be 

 due to carbonate of lime for fertility. Colman thinks that the be- 

 nefit of lime is merely mechanical, except where there is oxide of 

 iron, and that is properly neutralized by lime. But after all our the- 

 ory on the subject, facts alone should guide us in actual practice. 



Chairman — In our limestone districts, lime is known to be of ben- 

 efit and is always used as a manure. On argillaceous soils, lime is 

 productive of fine effects. The marl of New-Jersey when applied to 

 the sandy soils, produces the happiest results. Without lime, many 

 lands become sour, producing little grass and much sorrel. Many 

 farmers put too much lime on their land, and others not enough. In 

 all these cases, we must judge by the results of the majority of cases, 

 for all rules have exceptions, which however only prove their general 

 truth. As to the Russian tracts, and the reasoning, they are very 

 differently situated, perhaps, and we have no certainty w^hatever that 

 ■what is true of them would be so in this far distant region. Why 

 do our farmers prefer a limestone country? New comers in the west 

 seek for such land. 



Dr. Underbill — I have used much alluvial matter on my farm. 

 These alluvial deposits vary much in quality. Some contain coppe- 

 ras (sulphate of iron,) and the fertilizing effects of these alluvials 

 are not perceived for the first year, unless lime be mixed with them. 

 When that is done, we have formed at the same time, real gypsum, 

 (plaster,) which is a good manure. The presence of lime in the 

 alluvial, at least prevents the injurious effects of the copperas. Some 

 of the alluvials, perhaps, contain no copperas or any other acid 



