May 1908.J 457 



Freshly-burned lime, when removed 

 from the kiln, will weigh about 90 to 

 95 lb. to the bushel, and when slaked 

 will make about three bushels in volume. 

 Good limestone is found in pockets in 

 coastal limestone ranges of the We-t 

 coast, between Cape Leeuwin and Car- 

 narvon ; also hu ge areas of good lime- 

 stone exist at the head of the Great 

 Bi^ht, from Israelite Bay to Eucla, 

 reaching 150 miles inland. A small de- 

 posit is known at Southern Cross. 



Magnesian Limestones.— Magnesian 

 limestones or dolomites vary very much 

 in their composition, and may range in 

 carbonate of lime from 20 to 80 per cent, 

 and in carbonate of maguesia from 10 to 

 60 per cent. The average of such lime- 

 stone when burned will produce a lime 

 containing from 75 to 85 per cent, of 

 calcium oxide, and 5 to 20 per cent, of 

 magnesium oxide. Magnesian lime 

 weighs about 75 to 85 lb. to the bushel, 

 and when slaked will make about two 

 bushels for one by volume. There is a 

 small deposit of this rock at Milie Soak, 

 near Cue. 



Oyster Shell Lime.— Oyster shell 

 coutaius from 90 to 95 per cent, of cal- 

 cium carbonate, and will produce when 

 burned a comparatively pure lime, 

 which should contain from 85 to 95 per 

 cent, of pure calcium oxide if it has not 

 been excessively mixed with ashes in 

 burning. Freshly-burned oyster shell 

 lime weighs about 6n lb. per bushel, and 

 will make when slaked about two and a 

 half bushels for one by volume. Oyster 

 shells suitable for burning are to be 

 found in most of the estuaries in the 

 coastal districts. 



Slaked Lime.— The process of 'slaking 

 is the taking up of water, either from 

 the air or by water being poured over 

 the lime. The lime when, it has absorbed 

 all the water it. can forms calcium or 

 lime hydrate. It also absorbs some car- 

 bonate acid from the air, and forms car- 

 bonate of lime. 



The Maryland Agricultural Experi- 

 mental Station recently published an 

 article on this subject, from which it is 

 easy to ascertain the amount of water 

 required to slake differeut classes of lime 

 and the increase in bulk and weight due 



Scientific Agriculture. 



to slaking. 



Good stone lime 

 Magne.iastona lime 

 Oyster Shell lime 



& g 



lbs. 



93 

 8o 

 6o 



Weigh! 

 slaking 



)f Bus. 

 slaking. 



Weight per 

 bushel 

 after slaking. 



Total 

 after ! 



No. < 

 after : 



lbs. 







135 

 no 



100 



3 

 2 



2i 



45 

 55 

 40 



Gas Lime.— Quicklime is used at the 

 gas works for removing the impurities 

 from the gas. After the lime has been 

 saturated with these impurities it is of 

 no further use to the gas manufacturer, 

 and is sold for agricultural purposes 

 under the name of gas lime. It varies 

 greatly in composition, aud contain, the 

 sulphides and sulphites of lime, which 

 are injurious to the young plants it the 

 lime is applied too fresh. The action 

 of the air on these sulphides and sul- 

 phites changes them to sulphate of lime 

 (gypsum), therefore the exposure of 

 gas lime to the weather for some time 

 improves its agricultural qualities. Its 

 weight is about 65 lbs. to the bushel. 



Gypsum, or Land Plaster is a 

 combination of lime with .sulphuric 

 acid forming sulphate of lime. It occurs 

 in Nature in large deposits, forming 

 beds of rock, which are ground to a 

 fine powder for commercial purposes. 

 It varies in colour from white or light 

 yellow to gray. It is of advantage to 

 place gypsum in stables, etc., as it 

 absorbs the ammonia given off from 

 the manure, aud can afterwards be 

 applied to the soil. A little gypsum 

 mixed with the manure heap helps to 

 retain the ammonia which would other- 

 wise be lost. Gypsum is also stated to be 

 able to set free the potash contained 

 in the soil, and make it more readily 

 available as plant food. Some excell- 

 ent deposits of gypsum have found at 

 Dongarain this State. 



Marl is the term applied to deposits 

 which contain a large quantity of parti- 

 ally-decomposed shells. These are de- 

 composed by exposure to weather, and 

 such soils contain large quantities of 

 lime, which, when burned furnish a 

 supply of quicklime. 



Value of lime as a manure.— Al- 

 though all crops contain more or less 

 lime in their composition, the amount 

 is so small that it is hardly worth con- 

 sidering, aud suffi/jieut lime for the 

 requirements of all crops is to be found 

 in almost all soils. The quantity of 

 lime taken from the soil by a heavy 

 crop varies from 10 lbs. per acre iu a 

 crop of cereal to 90 lbs. in the case 

 of clover. 



It is the chemical action of lime on 

 the soil which gives it, its value, by 

 making the plant food readily avail- 

 able. This is brought about by the 

 action of the lime in decomposing the 

 mineral matter in the soil. 



Lime also hastens the decomposition 

 of organic matter and inert nitrogen- 

 ous compounds of humus in the soil 

 and promotes the formation of ammonia 

 and nitrate compounds from the same. 



