40G 



all of the utmost importance iu farming*, and are, of course, not indicated 

 by any analysis. 



Dr. Voelcker, however, would not be considered as regarding sucli 

 analyses as of no value, since in many cases quite the contrar^^ is the 

 fact. Tor instance, it is easy to determine whether a soil is deficient iu 

 lime or not, and thus ascertain whether it is proper to impart a dressing 

 of this mineral. It is also known that potash salts may be applied with 

 great advantage on some soils, w^hile on others their fertilizing effects 

 are scarcely perceptible ; and the determination of the question whether 

 there be enough potash iu the soil will enable us to decide upon the 

 proper action iu this respect. 



Again, it is possible to ascertain, by finding whether there is potash 

 in clay, as to its being benefited by burning; burnt clay being an 

 excellent fertilizer if the clay contains undecomposed silicates of potash ; 

 but the expense of this process would be entirely wasted if the clay be 

 naturally poor in alkaline silicates. Again, peaty soils are often com- 

 pletely barren, this condition being due, in most cases, to the i)resence 

 of sulphate of iron and finely divided iron pyrites, so small an amount 

 as ^ per cent, of the former being quite sufficient to render a soil entirely 

 unproductive. 



We can also ascertain by analysis whether a soil contains an excessive 

 portion of one or more matters otherwise useful to vegetation, such as 

 nitrate of potash, chloride of sodium, &c. It appears to be the fact that 

 all soils w^hich contain readily soluble salts, in quantities admitting of 

 precise determination, are more or less unproductive, although the salt 

 may be a very eifective fertilizer when applied in a weaker solution. 

 Thus, a soil containing ^l per cent., or even less, of common salt hardly 

 grows any crop ; this being the case with land inundated by the sea. Such 

 a proportion, indeed, of any substance is much greater than could at any 

 time be applied with safety, while very minute quantities are frequently 

 of the utmost efficiency; for so small a quantity as 50 pounds of nitrate 

 of soda, applied to an acre of grass laud, or to wheat or barley, and 

 thoroughly washed into the soil, will produce a most marked effect iu 

 the darker green color and greater luxuriance of the herbage compared 

 with the portion not so treated. One hundred pounds of ammonia 

 applied to an acre of land, in the shape of sulphate or of chloride of 

 ammonium, has been known to raise the average produce of wheat 20 

 bushels, with a corresponding increase of wheat straw ; and 300 pounds 

 of superphosphate of lime, of good quality, has been found to increase 

 the turnip crop in favorable seasons from six to ten tons per acre. 



If a man wishes to make a living by farming, Dr. Voelcker thinks 

 that at least from three to five times as much of all the more important 

 fertilizers must be put annually upon the land as is removed from it in 

 the crops, a depreciation in the crop resulting when a materially less 

 amount is applied. 



Effect of keeping flour in eaerels. — As is well known, flour 

 kept in barrels for a long time often acquires a peculiar odor, supposed 

 to be derived from the barrel. Professor Poleck, of Silesia, has lately 

 made a careful examination of such flour, and has ascertained that this 

 smell actually indicates an incipient decomposition prejudicial to bread- 

 making, the gluten of the flour having in jiart become changed into a 

 soluble body. Thus, while sound flour preserved in sacks contained 

 11.06 per cent, of gluten and 1.41 per cent, of soluble albuminous mat- 

 ter, four other specimens of flour taken from different barrels were sev- 

 erally composed of 8.37 per cent, gluten to 2.14 per cent, soluble al'ou- 



