EFFECTS PRODUCED BY SULPHATE OF SODA. 331 



Home, of Edinburgh, observed that these salts produced a beneficial 

 effect upon vegetation. Applied to growing corn, they increased the 

 produce by one-fourth. Other experiments, since made in Germ-any, 

 have shown that they may be applied with manifest advantage both to 

 field crops and to fruit trees (Sprengel), but the price has hitherto been 

 considered too high to admit of their being economically used in ordinary 

 husbandry. 



The manufacture of sulphate of soda in England, however, has of 

 late years become so much extended, and the price in consequence so 

 much reduced, that I was induced in the spring of the year 1841, (when 

 the publication of these lectures was commenced,) again to recommend 

 it to the attention of the practical agriculturists of the country — as likely, 

 either alone or mixed with other substances, to increase in many locali- 

 ties not only the produce but the profit also to be derived from the land. 

 (See Appendix, also published at the end of this volume, — " Suggestions 

 for Experiments in Practical Agriculture," No. I.) Many experiments 

 were in consequence made in various parts of the country, the details of 

 some of which are given in the Appendix. When applied at the rate of 

 half a cwt. of the dry salt (or one cwt. of crystals) per acre, it produced 

 little effect upon the hay crop, the quantity being probably too small. 

 Apphed to hay and rye, at the rate of 84 lbs. of the dry salt, and to pota- 

 toes at the rate of 100 lbs., it gave per imperial acre, with 



Hay . . 

 Winter Rye 

 Potatoes . 



The grain of the dressed rye was much heavier than that of the other, 

 and, though nitrate of soda and sal-ammoniac applied to other parts of 

 the same field caused a larger increase in the crop of rye, yet the increase 

 obtained by the use of the sulphate was cheaper per bushel than that ob- 

 tained by the use of either of the other substances. 



On beans and peas also the effect produced by it (Appendix, page 23,) 

 was very striking — its action being exerted not upon the straw but upon 

 the pods, increasing their number and enlarging their size. 



The results of these experiments, therefore, are such as to encourage 

 further trials. The quantity applied should not be less than one cwt. 

 of the dry salt per acre, and it should be put on either in the state of a 

 very weak solution witli a water-cart, or sprinkled on the young crop 

 when the ground is moist or when rain is soon expected. 



4°. Sulphate of Magnesia {Epsom Salts) was found by Dr. Home to 

 promote vegetation almost in anequaldegree with the sulphates of potash 

 and soda, but the usually high price of this compound, among other 

 causes, has hitherto prevented it from being tried upon an extensive 

 scale. The manufacture of thiS article also has of late years, however, 

 been so much extended and simplified, that the refined salts for medi- 

 cinal purposes may be purchased as low as 8s. a cwt. (at Messrs Cook- 

 son's, Jarrow Alkali Works, near Newcastle,) and the impure salts of the 

 Yorkshire and other alum works at a much lower rate. So much capi- 

 tal indeed has now been embarked in the manufacture of the sulphates 

 and (arbonates of soda and magnesia (p. 192), and i: is so desirable 



