Last month it was said, among "Answers to Correspondents," that "gas lime was worthless as a manure." This has brought us the following letter on the subject, which we give entire:

"In the March number of the Horticulturist you say 'lime refuse of the gas works is worthless as a manure.' I have used this article some in composting with swamp muck, and on a fallow last summer; and my ideas about it are so very different, I am inclined to ask you to favor us with the reasons why you condemn it.

"I am satisfied there is in most of our soils, of whatever name, a vast amount of valuable, yet inactive, vegetable matter. Beside this, Providence has collected, (for oar use, no doubt,) in every part of our land, immense beds of muck, of itself sour and dead, but which may be converted into active fertilising manure. This can best be accomplished by the use of alkaline so/la These will render this otherwise dead and inactive mold available to plants. They also, if wisely applied, attract ammonia from the atmosphere, promote decomposition of the soil, and themselves decomposed by the power of the plant enter largely into its formation. Now, according to Prof. Johnston, this lime refuse, after a little exposure to the air, is more than one-half carbonate of lime - one of the best alkaline salts, possessing great quickening power. About one-fifth is sul-pKate of lime (gypsum). This, we all know, is good. About ten per cent is water and coal-tar; two per cent Prussian blue; and three per cent alumina and oxide of iron. If these are facts, why is this lime worthless? I ask for information.

T. C. Maxwell. - Geneva, N. Y".

And our excellent contemporary, The American Agriculturist, has the following:

" Lime refuse from the gas works is pronounced worthless as a manure. We should like to know the evidence on which this opinion is based. A large per cent of it is still caustic lime, and we have never seen any evidence that it would not answer to decompose peat and coarse vegetable matter as well as. other lime. If we recollect rightly, the late Professor Norton recommends it for this purpose. It is the cheapest source of lime acesssible to those who live near our large cities* A farmer near us uses it in large quantities, and we have never heard that it was not satisfactory in its action. If any of our readers has had experience in its use, we should like to have their opinions, and the reasons for them".

With due deference to these authorities, we have a decidedly poor opinion of lime rubbish from the gas works. We shall be as glad to learn that it is thus valuable as any one else, for we have a pretty large interest in the matter of manures. 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 circumstances. We have seen an analysis by Prof. Johnson, in which he found in 112 lbs., 56 lbs. of water, 20 lbs. of carbonic acid, and 86 lbs. of lime and sulphur. This 86 lbs. 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 discharging sulphuretted hydrogen with vapor of prussic and other malignant gases, its sulphur gets oxygenated into sulphuric acid - two volatile products alike detrimental to plants".

After all this, it may possess a certain value for mixing with muck, or other material, to form composts, but does it possess sufficient value to be worth hauling, when man and horse labor is high, and when fresh lime and gypsum can be had at very moderate prices? This is the question with us. How can a large per cent. of it remain caustic, as the Agriculturist says, after the process it goes through in purifying gas? To get at its true value, we must ascertain what proportion is useful as a manure, or for compost; then count up the cost of hauling, spreading, turning, and preparing for use. The great item of expense for manure, with us, is the labor of men and horses in getting it We await more particular information.

Gas Lime #1

The Mark Lane Express says, with regard to this material, that "the gas lime must not be applied, in a fresh state, to any crop, but should be mixed with two or three times its weight of earthy or vegetable mould, and then turned over repeatedly for at least twelve months. It will then be fit for applying to the land. It will be most appropriate lor clover or grass lands. From fifty to sixty bushels of the gas lime, prepared as before mentioned, may be used per acre in the autumn or spring".