148 THE YEAR-BOOK OF AGRICULTURE. 



thrown out with the tar. It is a most valuable fertilizer, containing, in some cases, as much 

 as one and a half pounds of sal-ammoniac in the gallon. It may be used to promote the 

 fermentation of peat or couch-heaps, or may be mixed with any earthy or carbonaceous 

 composts. In England, it has been used, in some cases, in conjunction with saw-dust, and 

 gave very beneficial results. If applied to grass-land in too large quantities, it is liable to 

 scorch the surface ; but, diluted, it produces fine, dark-coloured herbage. The lime-water of 

 gas-works is also' a potent fertilizer ; but hitherto it has been little used. Thte lime em- 

 ployed to purify the gas is, to a certain extent, liouified ; and, after considerable evaporation, 

 a quantity of fluid, somewhat viscid, and smelling strongly of hydro-sulphuret of ammonia, 

 is run off to an underground tank. This lime-water, about five hundred tons of which are 

 annually produced at the Edinburgh Gas-Works, has hitherto been given for the carting 

 away. One or two farmers have used a. good deal of it ; but very large quantities are still 

 allowed to run to waste. If mixed with bibulous substances, more especially if they are 

 capable of being fermented, an excellent compost for use, along with other manure, will be 

 produced. Gas-tar may also be employed in a similar manner with advantage, only it is 

 necessary to use it rather cautiously and along with other substances, or it may injure the 

 crops to which it is applied. Transactions of the Highland Agricultural Society, Scotland. 



In regard to the value of gas-lime, great difference of opinion exists among American 

 agriculturists. Much of the gas-lime, as it comes from the purifiers, is in the state of 

 hyposulphite of lime, most of which, by exposure to air, moisture, and vegetation, passes 

 into sulphate of lime, (gypsum.) Some carbonate is also undoubtedly formed. So long 

 as the lime remains a hyposulphite, its value for agricultural purposes cannot be very- 

 great. The hyposulphites, as is well known, are all depilatories or hair-removers. The 

 depilatory powders sold by druggists are compounds of this character. We have heard 

 of an instance where a gentleman farmer added fresh gas-lime to his hog-pen, with the 

 intent that the swine should incorporate it with the compost-heap. This was effectually 

 accomplished; but at the expense of the bristles and hair of the hogs, which was, in a 

 great measure, removed during the operation. The editor of the Horticulturist, who 

 has a poor opinion of it, says: Some years ago we were informed, by a very intelligent 

 gentleman near Toronto, that it was not worth hauling two miles ; that they had tried 

 it to their entire satisfaction ; yet it might be valuable elsewhere or under other cir- 

 cumstances. We have seen an ^analysis by Professor Johnson, in which he found in one hun- 

 dred and twelve pounds fifty-six pounds of water, twenty pounds of carbonic acid, and thirty- 

 six pounds of lime and sulphur. This thirty-six pounds is about the same as gypsum, and is 

 all we should consider of any particular value. 



Dr. Ure, the celebrated chemist, has described it as "vile refuse, which should be buried 

 many fathoms deep in some barren region ; for, when spread on the farmer's field, after dis- 

 charging sulphuretted hydrogen with vapor of prussic and other malignant gases, its sulphur 

 gets oxygenated into sulphurous acid two volatile products alike detrimental to plauts." 



The following is a paper on the use of gas lime, by J. F. W. Johnston, of England: 



Refuse Lime of the Gas Works. This refuse lime consists of a mixture of carbonate of lime 

 with a variable quantity of gypsum and other salts of lime containing sulphur, and a little 

 coal-tar and free sulphur, the whole colored usually by a little Prussian blue. The follow- 

 ing table exhibits the composition of two gas-limes which have been analyzed in my labora- 

 tory from Edinburgh and London. The first two columns show what they were when sent 

 to me ; the second two, what they will become after long exposure to the air, after being made 

 into compost, or after being, thoroughly and for a length of time incorporated with the soil. 



This table shows that these gas-limes differ much in composition, especially in the propor- 

 tions of sulphur or of the acids of sulphur they contain. This arises chiefly from the kind 

 of coal which is employed in the manufacture of gas in different works. 



The most marked difference between the two samples here analyzed is in the compounds 

 called sulphite and hyposulphite of lime. The latter of these substances dissolves readily in 

 water, and its presence in such very different proportions satisfactorily accounts for the very 

 different effects which have followed from the application of gas-lime to the land in different 

 districts. The rains dissolve the hyposulphite and the sulphuret, and carry them down in 



