462 TrAKS ACTIONS OF THE AMERICAN INSTITUTE. 



analagous to tliat by which iron pyrites or sulphuret of iron is made 

 to yield copperas, the sulphnr and iron both oxj-dizing, the one to 

 form sulplniric acid, the other to constitute basic oxyd of iron, and 

 these two products uniting to form sulphate of iron or copperas. It 

 will be seen that when the removal of the injurious constituents has 

 thus been secured it is brought into the condition simply of an 

 impure carbonate of lime, and may be applied in the same manner. 

 To bring it to this state it must be exposed to air and moisture. 

 This can be done by leaving it fur a few months or weeks in piles 

 under open sheds, which is the better way, or by applying it in the 

 autumn and leaving it upon the surface until spring. If the latter 

 course is followed, probably as much as seventy or eighty bushels to 

 the acre could be applied without mischief, but if one-third of the 

 same quantity bf the raw or fresh material were applied in the 

 spring it would be likely to kill the young plants, and would on 

 some varieties of seeds prevent germination. As regards the old or 

 prepared material it is somewhat milder than ordinary slaked lime, 

 and thirty bushels per acre applied in the spring would be an aver- 

 age standard for its use. It is believed to be the most beneficial to 

 old and tough sward, to orchards and potatoes. Its peculiar odor, 

 arising from the presence of a very small proportion of tarry matter, 

 gives it a certain efficacy in repelling insects, worms, etc., and for 

 this reason strewn sparingly over young turnip plants or harrowed 

 in before sewing, its use is preferred in some cases in England to that 

 of common lime. On mossy lands and those recently reclaimed by 

 draining in the amelioration of muck, etc., gas lime, after due expos- 

 ure to the atmosphere, may be used in the same manner as common 

 lime. 



The disappointment experienced in attempting the use of gas 

 lime as a fertilizer has arisen for the most part from the exaggerated 

 claims that have been made in its fovor and the crude directions 

 given for its application. We need not refer further to the need of 

 removing the sulphites by continued exposure to the air, but a few 

 words should be directed to the statements made in the circulai-s of 

 those interested in its sale, that "it may be mixed at once with barn 

 yard manure and stable manure, expelling none of the valuable 

 gases, but fixing and retaining them fully equal to plaster." Old gas 

 lime, as shown by Prof. Johnston's analysis, of which mention is 

 made, may contain some thirty per cent of sulphate of lime or gyp- 

 sura, which by itself would be capable of fixing a proportion of 



