There are several questions in regard to drainage which are impor tant. What are the effects of drainage on land, and how these effects are brought about? How does this system of drainage affect the profits of the farmer, and in what way does drainage pay him? The first effect of drainage-for I cannot dwell upon them, but must put them down here succinctly-is to carry off all the stagnant or surface water; 2d, it relieves land of water where it accumulates below, by the filtration of the rain through the surface; 3d, it causes the rains, instead of running over and washing the land, to descend where it falls, and this is the perfection of thorough drainage; 4th, as the rain sinks into the soil, it carries with it a continual supply of fresh air, and thus administers new doses of air to the substance of the soil; 5th, it makes stiff soils more crumbling, so that this kind of soil, instead of being hard to work after drainage, requires but half the force to plow it; 6th, it makes the soil warmer. You remember that I told you, that evaporation cools the surface; of course, if the surplus water is carried off by drainage, the soil is warmer. Then it also enables the farmer to proseed to till his land much sooner after the rains fall, and thus get ahead of others who do not drain their lands. So in the spring and autumn, in the open weather, he who drains his land has great advantage. And there is another advantage; it benefits his neighbor as well as himself, keeping the mists and fogs of his own land from that of his neighbor, while the man who neglects this, injures his neighbor by the converse process. Another point to which I have alluded, and at which [ will glance now, is that by this means, you compel nature to do the artificial work of taking out from the soil what is injurious to it, much more cheaply than it could otherwise be done. I have spoken of the importance of the healthiness of a climate. Among the means of improving lands, this of drainage has been attended with one remarkable result, in contributing to human happiness. It happens that drainage, while it has improved the soil, has been the means of improving the health of large districts, a result which every benevolent man must contemplate with high satisfaction. Drainage is attended not only with these good effects, but it gives the farmer larger, surer and more valuable crops. Land that would once only grow oats, has in this way been made to grow wheat. Crops that were uncertain, have been made certain, and the product doubled in quantity.

On what land does it do this? on wet lands, no doubt; but when I tell you that it does so not only on wet lands, but on lands liable to be burnt up with the sun in summer, it may excite surprise. I have a uggestion to make in regard to lands thus liable to be burnt up; but

of course, in making the suggestion, I do not intend that you shall go immediately to do it on a large scale, but that you should try the experiment on a small scale. But it is a fact, that on such land as I have described, thorough drainage has been found the most beneficial of all methods of improvement. In this neighborhood, you have sandy plains, and you have other stiff clay land. Now in summer, the sandy land bears the extreme heat, better than loam, and the loam better than clay; that is the soil which is most open, is least acted on by the sun. This is the case in the lands on the plains of Athens, of which I have spoken, which is liable to be burnt up by the sun.

Now if we consider the several causes by which this drought is produced, and how drainage affects it; you will see on what this experiment is founded. If the soil is merely burnt up by drought, and you suppose the roots to descend only to the depth of about 3 inches, it is obvious that the heat of summer dries up the land to the roots. But if by drainage, you open up the soil three feet deep, so that the rain, instead of flowing off the surface, descends through the soil, thus made pervious to it, the roots will grow deeper, and while the upper surface is dry, the drought does not reach the roots, which are thus enabled to live longer than they otherwise would. But there is another singular circumstance, with reference to soils that contain saline matter; potash is saline matter. The water with which it is saturated, comes to the surface, and evaporates, and this substance which is held in solution, is left on the surface, and kills the soil. Prof. J. here stated that he had sent him a specimen of the soil on the plains of Athens, for his examination and advice. On these plains, the grass grows luxuriantly in the spring; but as the sun grows more scorching, it gradually withers and dies. Prof. J. said that knowing the character of the rocks in that region, and that the sudden check to vegetation, was the results of the salt held in solution in the soil, and left upon the surface by evaporation the remedy was simple and easy; and that was drainage and ploughing. So that when the rain brought down the salt from the heights, it would also, run away with it, and not remain in the soil. Thus, you see, that the practice of draining, has been found to succeed, where it might have been least expected; and that it is an experiment well worth trying. I am sorry to detain you so long, but you will excuse me if I occupy a few moments, in answering the question, will drainage do in New-York; will it pay? I do not speak of this or that county, for I believe a discussion of this question, has already taken place, and that a great deal is to be found on the subject, in your volumes of Transactions; it is a discussion highly creditable in itself,

and from which I infer that you have confidence that it can be applied with profit, to certain parts of your State; but some general considerations, may be of use. The quantity of rain that falls, determines the quantity that remains. The quantity in New-York, is much greater than in Great Britain; yet we find in Great Britain, that it is not only necessary, but profitable. Now, the first question is, as to the quantity of rain that falls. Without any other data, I should say, that the quantity here, renders it probable, that drainage would do here. Knowing as I do, the profit of drainage, where there are but 24 inches of rain, I infer that where there are 40 inches, thorough drainage must also be profitable.

The way in which rain falls, is also important, and how many rainy days there are in a year. I did not anticipate that I should be drawn into this point, and cannot tell the number of rainy days in New Brunswick. During four months, spent among the practical agriculturists there, and after a thorough canvassing of the whole subject, I am satisfied, that thorough drainage, though expensive, can be safely recommended. In St. Johns, where it rains most, there are 74 rainy days in a year, In New-York, 111; in Rochester, 115. Here is another argument which strengthens the probability, that thorough drainage, might be resorted to with profit. I do not recommend it, nor do I want you to adopt my opinions, because I state them here. It was my duty to go into every county in England and Scotland, with a view to this subject. I conversed with the most experienced, practical men, in whose way I was thrown. The results are what I now tell you; that drainage has been found effectual, in a country, where they have less rain than you; where the soil is not stronger, or heavier than yours, and where the number of rainy days is not greater than at the places I have mentioned in your State. This, being so, whatever opinions you or I may entertain, the inference is irresistible, that the system may be tried with eminent advantage to the practical farmer; and I would say that there is a probability, that thorough drainage may be the means of gradually improving your soils. I think it is worth while seriously to consider, whether you may not turn it to your own individual advantage, and thus contribute to the wealth of all.

LECTURE SIXTH.

RELATIONS OF CHEMICAL PHYSIOLOGY TO THE PLANT, AND THE MODES OF PROMOTING ITS GROWTH.

GENTLEMEN: There is one aspect in which the art of farming seems exceedingly simple. If you look at the procedure of one of those who cultivates the rich land of the Genesee valley, which is a rich clay mixed up with a calcareous gravel, you see the routine which he pursues in the alternation of his crops, and you observe that he pursues this course regularly every third year, and you may naturally infer that this is a simple art, requiring no mental exertion to carry on all its details. It is because this art appears so simple, that farmers themselves are unwilling to believe that there are any difficulties connected with it, that it has been generally supposed that very little knowledge is necessary to practice such an art; that it needs very little intellect or intelligence, and that if a man is fit for nothing else he has brains enough for this. Besides the obvious effect which this idea has upon the agricultural community itself, it has its effect also in lowering the character of the agricultural body in the estimation of the other professions. Now, if the agricultural body has reasons to complain of the estimation in which they are held in other quarters-and it prevails among us and every where it appears to me that these persons themselves, that is the class of agriculturists who refuse to believe that there is any difficulty in this art, such as I have described, are themselves to blame for a state of things of which they complain. Those are really the friends of the agriculturist who show that this department of art can be made more certain in its results and more lucrative by the application to it of the various branches of natural knowledge, and that he is indeed the friend of the farmer who seeks to bring to bear upon it the results of scientific research, and to show the world that there is really something complicated in this apparently simple art.

I have been led to these remarks in consequence of having reached that stage in my progress which brings this most prominently in view;

that is, the relations of the soil to the science of Chemistry. You will recollect I showed you at our last meeting, that the soil is a complicated material, containing a great many substances, in different proportions, and on which proportions the quality of the soil depends. You will recollect that I showed you that the result of chemical research was the development of the fact that all fertile soils contained a certain number of certain things; and now I come to show you that all fertile soils do and must contain them, and that if certain of these things are wanting no soil can be fertile. To show the necessity of this I must bring under your notice the composition of the plant.

I explained to you at our last meeting, that if I take a vegetable substance and burn it nearly the whole of it burns away, leaving but a small quantity. I advert to this to show you that the same thing is true of the soil-as part of the soil burns away, and a part of every plant-but a certain quantity of each is left behind. Both contain a certain quantity of combustible and incombustible matter. In both, the first is organic, the second inorganic, or mineral matter. But they differ in this, that the part of the soil that burns away is very small compared with the whole mass, while in a plant the converse is the case; the largest portion of the plant burns away; so much greater is the combustible portion of it. [Prof. J. here pointed to a table showing the different quantities of ash left after burning different vegetable substances, wood, wheat, straw, hay, tobacco, &c.] Thus you perceive, said he, that in the case of the plant, first, the quantity of mineral or incombustible matter is less than in the soil, and second, that the quantity of combustible or organic matter is greater. Now, as the plant consists so largely of combustible matter, in order that we may know something of it, I must make you acquainted with some substances of which I have not yet spoken, as it will be necessary to illustrate not only what I have to say to-night, but at our next meeting. The part of a plant that burns away contains six different things, in different proportions-one or two of them in large proportions. This, [holding up a piece of it,] is common wood charcoal. If wood is ignited and closed from the access of air, it becomes charcoal. It contains all the mineral or incombustible matter of the plant. This charcoal, therefore, is a material representation of carbon. There are various forms of carbon, the diamond is one. But carbon is one of four or five other substances which constitute the combustible or organic portion of plants, and forms far the largest portion of it. Another substance is oxygen; a third hydrogen; a fourth nitrogen; a fifth sulphur; a sixth phosphorus.

Take any one plant, and the part that burns away contains these six different elements; but there are certain plants that do not contain all