Mr. B. P. WARE of Marblehead. Market gardeners make what they call a compost heap for the purpose of producing fermentation. Is the gain that the farmer or market gardener will derive by applying that manure after it has gone through the process of fermentation, which is supposed to render it more readily available as plant food, greater than the loss which will be occasioned by the process of fermentation?

Professor WHITCHER. That is a very difficult question to answer, because nobody can tell. I suppose it might be accepted as good proof that the advantage is greater than the disadvantage, from the fact that most market gardeners do that very thing. When we get down to the average judgment of any particular class who have studied their business as market gardeners have done, their judgment is very liable to be right. I have faith enough in humanity to believe that this is true, and when I find the teachings of what I believe to be science run contrary to that, I am pretty careful to look the teachings over again, to see if somebody has not made a mistake. I am inclined to think that the advantage is not due, as you have suggested, to the plant food being rendered more readily available, because I do not think that is true, but I think it is in a better mechanical condition, and therefore more generally distributed through the ground. I think it is due more to the mechanical condition than to any chemical change that results from fermentation. Fermentation does result in a loss of nitrogen; but, on the other hand, there may be such a supply of nitrogen left in the manure that the greater uniformity with which it can be distributed through the soil more than makes up for any loss in the process of fermentation. I think that may be true; but, on the other hand, I do not know but that there are other ways of getting the manure in just as good shape, and still save the nitrogen. I think it could be done. I should want to try it if I were engaged in that kind of work.

Secretary SESSIONS. The first question that was asked in regard to spreading manure limited it to manure that was put on the ground late in the fall, and remained through the winter. Would you answer the question in the same way, if the manure was spread on the land in August or September?

Professor WHITCHER. I would rather have it put on the land in August or September than late in the fall or in the winter.

Professor WHITCHER. Because the fall rains would wash the plant food into the soil, and there would be no danger of its running off, as there is when the soil is frozen. I believe the safe rule, the correct rule, is to apply manure just as soon as possible after it is produced. If it lies in the barn cellar it ferments, and there is some loss; if it lies under the eaves there is a washing out, — a big loss. If it is put onto the soil as soon as produced, whatever leaching there is goes into the soil. I would draw out manure any day in the year after the field was cleared so that a team could get there, even if the snow were two feet deep. We practice this method, and I believe it is the correct one. Get it out of the stable and onto the ground as soon as possible. Putting manure on a field at any time, unless the ground is very steep, in my opinion does not involve any loss.

Mr. CHARLES PARKER of Holden. Would it not be far better to use a harrow or plough when it is put on the field in August or September, and cover it up?

Professor WHITCHER. Yes, it would be better because of the fact that, if the manure dries on the surface, it gets into very hard lumps; whereas, if it is worked into the soil, it will be kept moist. Still, that practice could not be carried out with us, because we draw it out when the land is frozen ; but I think the suggestion is a good one, that it should be mixed with the soil, if possible.

Mr. HERSEY. Is there not another loss in allowing manure to decompose in a heap, through the escape of carbonic acid gas? Is not that beneficial to the soil? When it escapes in the soil, does it not hasten the decomposition of the soil itself, and thus let loose the plant food that is in the soil, and may it not be also beneficial to the growth of plants? As common air contains only about 6 parts in 10,000 of carbonic acid gas, would it not be beneficial to the growth of plants to have some of it escape from the soil while it was escaping from the manure in the process of decomposition?

Professor WHITCHER. I do not think there would be very much of a point there, from the fact that plants do not take up carbonic acid through their roots; the carbonic acid of the plant is taken in through the leaves, and comes from the atmosphere; and, while the amount of carbonic acid in the atmosphere is very small, nevertheless it is always amply sufficient to supply the amount that is required for the growth of large crops. In other words, if we furnish everything else that the plant needs, the plant will take care of itself, so far as obtaining a sufficient quantity of carbonic acid.

Mr. HERSEY. What amount of carbonic acid do plants require?

Professor WHITCHER. There have been a good many experiments made, showing different percentages; but, if I remember correctly, there has been no advantage shown in increasing the amount above that contained in the atmosphere.

Mr. HERSEY. Is there not some German authority who tells us that plants grow best in eleven per cent of carbonic acid gas?

Professor WHITCHER.

Eleven per cent would be a pretty heavy dose of carbonic acid, and would prove injurious to most plants.

Mr. HERSEY. I know it would be; but, as the result of some experiment that was tried, it was stated that common soil contained from 37 to 125 parts in 10,000, but that wellmanured soil after a heavy rain, in warm weather, contained 1,300 parts of carbonic acid gas. I think it is well to bring this up, because I think it is one of the things that the experiment station should take hold of and ascertain beyond the possibility of doubt whether we are losing anything by losing the carbonic acid gas from our manures or not, and whether the common air has enough for the excessive growth of plants which we require. I have no doubt that there is carbonic acid gas enough in the common air for the growth of forests; but I very much doubt whether the average amount is sufficient for the growth which we demand in our gardens.

Professor WHITCHER. I would like to say, in connection

with that, that I do not see how we can very well regulate that matter. Even allowing that there ought to be more carbonic acid in the atmosphere than there is, how are you going to get it there or keep it there? The wind will blow it away. It has been thoroughly demonstrated that plants do not derive their carbonic acid through their roots. If we could control it, it would be all right; but, suppose we should get a little more carbonic acid over our corn field, our neighbor will get it, if he lives on the windward side. Mr. HERSEY. It seems to me that if we fill our soil at no cost with carbonic acid gas, a considerable portion of it would naturally escape to the air and surround the plants, and thus the plants would take up what they needed; and, if there was any left, it would be all well enough for the neighbors to have it.

Professor WHITCHER. If there was any possibility of appreciably increasing the amount of carbonic acid in the atmosphere, the increased consumption of coal that is going on at present ought to have had an effect before now; and yet the results of analyses show that the carbonic acid in the atmosphere remains practically unchanged. Of course we cannot tell absolutely, because the methods of determining the amount of carbonic acid in the atmosphere employed by the early experimenters may have been faulty; but I think there is no belief among scientific men that the amount of carbonic acid is increasing.

Mr. E. B. LYNDE of West Brookfield. My neighbor sitting here by my side, and I, have been discussing the question of manure. He practices spreading his manure on his grass ground and ploughing it under; I do not. My manure all drops into the cellar, and never freezes; but, notwithstanding that it can remain there until spring and never freeze, I carry it out as fast as it is made, no matter if the snow is two feet deep. I have never practiced ploughing manure under upon grass land. It seems to me that there would be likely to be a loss if it is treated in that way.

QUESTION. What is the character of your soil?

Mr. LYNDE. A sandy loam.

Secretary SESSIONS. I wish Professor Whitcher would touch upon the matter of leaching, in answering that question.

Professor WHITCHER. The practice of the gentleman accords entirely with what I believe. I do not believe in burying manure. There used to be a notion that manure had a wonderful tendency to climb, and that we would lose a great part of its value in the atmosphere if it was not buried pretty deeply; but the fact is that the loss of manure is in the other direction, - downward. The water that passes through the manure soaks down into the subsoil, especially where you have a sandy subsoil. It It goes down much faster in a subsoil of that character than it does in a clayey one. That is one danger in burying it too deep. Again, decomposition does not take place so rapidly as when it is near the surface, and therefore it is not so rapidly made available for the crop. My belief is that it should be kept near the surface and mixed as thoroughly with the soil as possible, not carrying it down more than two or three inches, and then let the water wash the plant food down, and distribute it through the rest of the soil. The loss, as I have said, is downward, not upward.

Mr. LYNDE. I am in the habit of using sand as an absorbent. Now, is that the best way to save the plant food, and does it pay? Of course there is an expense in carting the sand in, there is a good deal of time spent in spreading it in the gutter, and then it takes time to move it onto the field. Is that practice a paying one?

Professor WHITCHER. Perhaps I can give my idea of that by stating what we do. We buy sawdust and go five miles to get it, whereas we could get sand for much less, and would only have to go about two hundred rods to get it. We had rather pay ten times as much for sawdust, and take all the labor of hauling it the extra distance, than use sand. Mr. LYNDE. Why?

Professor WHITCHER. I will tell you why. In the first place, the sawdust is very light to handle. In the second place, if you have cows you can keep them clean much more easily. If you use sand, it gets onto their udders and drops into the milk. You may say that you can clean the udders and get the sand off, but the man who will do that must be a better man than I can hire. Another thing is, a given amount of sawdust will absorb a great