i 64 LESSONS IN CHEMISTRY. 



60 per cent of phosphate of lime. Many hundred tons of 

 these coprolites have lately been used for manure, and they 

 have even been applied dissolved in sulphuric acid, as a sub- 

 stitute for " vitriolized bones," with the very best results. It 

 has ah'eady been mentioned (132), that in the Greensand and 

 other rocks, constitutmg what is termed the chalk formation^ 

 which covers a considerable surface in England, and in Ireland 

 extends, with occasional inten-uptions, from Moira in Down 

 to Lough Foyle in Deny, a considerable amount of phosphate 

 of lime has also been found to exist. It is chiefly in the 

 Greensand, which appears to have been used several years 

 ago in some parts of Antrim, with good effects, as a manure 

 for both potatoes and oats, that that valuable substance has 

 been discovered.* 



258. Sulphate of Lime. — This substance, which is also 

 known by the names oi plaster ofParis^ alabaster^ and gypsum^ 

 has already been recommended as an important addition to 

 the manure heap (183); but, besides its use in the preseiTa- 

 tion of other manures, it has, for a very long period, been 

 extensively applied as a fertilizer in various parts of Europe, 

 and is at present one of the most favourite applications of the 

 farmers in many parts of the United States of America. At 

 one time, it was believed that it was capable of increasing 

 the produce of every description of crop; but, from the 

 results of careful experiments made by experienced agricul- 

 turists, both in France and England, more correct opinions 

 of its fertilizing qualities are now entertained. The use of 

 this manure was considered of so great importance in France, 

 that a particular inquiry into the circumstances connected 

 with its employment and effects, was considered worthy of 

 the attention of the government, and a report on all the 

 information collected was made to the Royal Central Agri- 

 cultural Society of France. " The following series of ques- 

 tions and answers, I believe," says Boussingault, " embrace 

 most of the points of any interest connected with the employ- 

 ment of gypsum. 1 St, Does plaster act favourably on arti- 

 ficial meadows? Of 43 opinions given, 40 are in the 

 affirmative, and 3 in the negative. 2d, Does it act favour- 

 ably on artificial meadows, the soil of which is very damp? 



* A nodule, discovered in the greensand, near Can-ickfergus, by Mr, 

 M^Adam, and examined in my laboratory, was found to contain so much 

 as 42 per cent of phosphate of lime. , 



