the ridges above, no marks are to be seen, and I never have known in 20 years that the high land has been touched, while on the low land almost every shower, it is struck.

Professor STERLING. The low land is moist and the tall trees attract the electricity. If the conducting material is the same, the high ground is the most prominent, but if the hill is dry and the low land is moist and covered with tall trees, that changes the conditions entirely. I think it is owing to the fact that the induction takes place in the trees more on account of the moist soil in which they grow, than upon the hill. I am sorry to hear the expression that lightning-rods are played out. I must acknowledge that rods as they are ordinarily put up are, or ought to be played out, but at the same time I think the principles that I have advanced in this paper can be asserted, and that a building can be protected. And I think it will pay to go to the expense of the rod, put up in the proper way on a building.

Mr. STILSON. I wish to ask the Professor this question. In the case of the discharge, and to save human life where a person may be struck, what are the remedies always at hand, to be used temporarily by other persons present?

Professor STERLING. I don't feel hardly competent to answer that question. I have not looked at it specially; I am not posted: know the common remedies are cold water, etc., but I cannot speak with authority on that subject.

Mr. CHEEVER, of Rock county. There is no dwelling house in Wisconsin where there is not always a moist spot about it; there is always a place where the slops of the kitchen are deposited, and that is always moist.

Mr. WHITING, of Fox Lake. I would enquire if there is any such form in existence that can be cheaply procured. I am aware that a tubular form can be procured in the form of gas pipe at an expense that far exceeds the ordinary rods. The Professor said it was also important that they should be intimately connected, and that the surface should be large. I would like to ask if a tube of sheet iron could be made to answer the purpose. Would it answer to make a tubular rod of sheet iron, and have it connected by clinching in the ordinary way? Would the connection be sufficiently close? And then again, would it be necessary that the rod

should be solid, or would iron rolled up without being welded and connected at the edges be sufficient?

Professor STERLING. You know how the scroll rod is constructed. They are scrolls which are inserted into each other. I do not see any objection to that. If you have parts of iron, they ought to be intimately connected on the surface; and they are generally made to screw into each other. In regard to the practical way of effecting this, I don't know that I can give any opinion.

The rod which was manufactured at Janesville some time ago, a continuous copper rod without any break in it at all, in my judgment was one of the best rods we ever had. I believe the manufacturing of that rod has ceased. The edges were folded in, and it was entirely continuous, without any breaks in it at all, and in each of those parts where it was rolled you could put in wire to stiffen it if you wished. This scroll rod I think is very good if it is properly put up.

MR. BENTON. Is not the common inch gas-pipe made of galvanized iron with the ends screwed together firmly, a good conductor? Professor STERLING. I meant to have tried an experiment in regard to galvanized iron, as to its conductive quality, but I did not have time. It is stated in Chamber's Encyclopedia that it is a better conducting metal than iron, but iron in the form of those gaspipes is just as good as though it were solid, as you have less material and more surface.

OBJECTS AND METHODS OF CULTIVATION.

BY PROF. W. W. DANIELLS, UNIVERSITY OF WISCONSIN, MADISON. In all the operations intended to aid his crops in obtaining food for a vigorous and productive growth, the farmer needs to regard the soil as the only source from which that food can be obtained.

Plants do, indeed, draw a large portion of their subsistence from the air. But the supply from that source is always abundant, and to effect it in any way either in quantity or quality is impossible for man.

The soil is the great store-house of the mineral constituents of plant food, and it is to the increase of these constituents, either directly or indirectly, that the farmer must turn his attention.

To obtain this increase, he plows, harrows, cultivates, drains and

manures, and performs all the various operations that are included under the term "cultivation," regarded in its widest sense, including all the processes in use for the hastening of plant growth by the amelioration of the soil.

A soil is rock, that by the slow but constant action of natural forces, heat, moisture and the atmosphere has become disintegrated. Upon such pulverized rock plants have grown for innumerable years, and the decomposition of these plants upon the soil has supplied the surface with a stratum that is largely mixed with organic matter. This stratum is the arable soil which contains the greater part of the food that is immediately available to plants. It is that which is popularly known as the soil, and with which the farmer has to deal in his efforts to secure an abudant supply of nourishment for his crops, for to that end are all his efforts directed.

How is it, that the purpose sought is accomplished by the means used?

Nothing is added to the soil by plowing or harrowing, cultivating or hoeing. A field contains nothing after these operations have been performed that was not there before, and yet these are the means employed to supply through the soil, from year to year, that which, by the wonderful magic of plant-growth, shall bring the harvest with its hundred fold.

The mineral matter in agricultural plants is but a small per cent. of their total weight, and yet it is to supply that small proportion, the ash-ingredients and the nitrogen compounds, that all the labor of tilling is required. This food must all be taken up by the plant through its roots, and consequently must be in solution as it passes into the plant. But these ash-ingredients are many of them present in even the most fertile soils in exceedingly small proportions, so that if they existed in soils in a soluble form entirely, the large quantity of water that falls and is discharged through the soil would carry them away in solution, and the richest soil would thus soon become comparatively barren. Instead of being present in a soluble form, however, they are there mostly in the form of rock, which is affected but slightly by pure water.

Now the chief end to be gained by such mechanical operations as those of tilling the soil, is to supply to the plant these insoluble rock-ingredients of its food.

Every farmer understands that his soil is not in good condition

unless it is finely pulverized. The object of making it fine is twofold.

First, to allow the roots to readily penetrate it in search of that food which is present in so small quantities that it must be sought through a wide range of soil, and secondly, to put the soil in that mechanical condition best suited to changing the insoluble mineral food to a soluble form, in which state alone it can be utilized by the plant.

As before stated, the required change is produced by the air, by heat and frost, and by the action of natural waters which are charged with carbonic acid, and which have a much higher solvent power than pure water.

The processes of tilling are to put the soil in that condition in which these natural agents may most readily act upon it. This action takes place entirely upon the surface of the rocky particles, and consequently will be in proportion to the amount of surface exposed.

Now the extent of surface exposed to the action of a solvent is increased by increasing the fineness of the particles. Thus Magnus found that barley would grow and ripen seed in powdered feldspar, and Professor Storer matured buckwheat in quarry sand and freshly burned coal ashes. Had the material used in either of these experiments been coarse, instead of fine as they were, plants would not have grown in them. It is not enough that a soil shall contain all the elements required for plant growth, to make it fertile. The food must be dissolved, and the rapidity of its solution depends, other things being the same, upon the fineness of its particles. Hence the farmer breaks up his soil, bringing it into the finest possible condition, that the decomposing action of air and water may be rapid, and that the roots of the growing plants may be enabled to extend themselves through the soil to absorb any food there in readiness for them. Fineness of itself, however, is not enough. If it were, the heaviest clay soil would be more fertile than the lightest loam. The clay is too fine, so fine that the particles fit into the interstices, rendering the whole compact, thus excluding the air and preventing that rapidity of action which it is the object of cultivation to attain. But the highest degree of fineness consistent with lightness and porosity is always to be desired.

Cultivation of soils then, is, in one sense, analogous to the masti

cation of food by animals. It is preparing the food for the digestive organs of the plant.

The difference between a fertile and a sterile soil is often attributable to this one cause, a want of sufficient porosity to allow the air and moisture to enter it and decompose the mineral matter, changing such as is needed to that form capable of being taken up by the roots of plants.

This is the great difference between soils and subsoils, and the latter may be made fertile by the same pulverization and exposure to which the former has been subjected. It is principally by the gradual chemical changes in the composition of the soil brought about by the decomposing action of heat, moisture and air, that soils are continued in a state of fertility from year to year. These natural forces are continually at work for the farmer, and their work will be well and thoroughly done, in proportion to the opportunity he gives them, by furnishing a light, porous and well pulverized soil.

Were there, then, no other reason for thorough culture than this one, it must be greatly to the interest of the farmer to cultivate well and thoroughly, to plow deep and keep his soil well stirred, in order that his crops may yield the largest possible harvest. But there are still other reasons why the soil's fertility is increased by its being finely pulverized. Those properities of soils that are usually termed "physical," those in which the action is mechanical rather than chemical, are also in a high degree dependent upon the fineness of their particles. The first of these to which I wish to call attention is the power possessed by soils of absorbing certain substances, and of condensing upon the surface of the particles of which they are composed moisture and gases existing in the atmosphere.

If a dry sponge be dipped in water and then squeezed until no more water can be obtained from it, it is not dry as before, but still contains a large amount of water, which exists, not as water, but as moisture held upon the surface of the particles composing the sponge. The amount of water so held, is in direct proportion to the extent of surface with which the water comes in contact, for the cause of the waters being held there is that surfaces have a strong attraction for moisture. Any one who has had occasion to thoroughly dry a glass tube or bottle, knows something of the persistence with which moisture adheres to the surface of glass. Soft