No apology will be necessary for the long extract which we are about to give, to any person who will read it with attention. It is from a lecture on Agricultural Science, by Dr. Madden, and we confess ourselves incompetent to condense or improve the language of the learned author. We think we are safe in saying that it has never been before published in America: "The first thing which occurs after the sowing of the seed is, of course, _germination_; and before we examine how this process may be influenced by the condition of the soil, we must necessarily obtain some correct idea of the process itself. The most careful examination has proved that the process of germination consists essentially of various chemical changes, which require for their development the presence of air, moisture, and a certain degree of warmth. Now it is obviously unnecessary for our present purpose that we should have the least idea of the nature of these processes: all we require to do, is to ascertain the conditions under which they take place; having detected these, we know at once what is required to make a seed grow. These, we have seen, are air, moisture, and a certain degree of warmth; and it consequently results, that wherever a seed is placed in these circumstances, germination will take place. Viewing matters in this light, it appears that soil does not act _chemically_ in the process of germination; that its sole action is confined to its being the vehicle, by means of which a supply of air and moisture and warmth can be continually kept up. With this simple statement in view, we are quite prepared to consider the various conditions of soil, for the purpose of determining how far these will influence the future prospects of the crop, and we shall accordingly at once proceed to examine carefully into the _mechanical relations of the soil_. This we propose doing by the aid of figures. Soil examined mechanically, is found to consist entirely of particles of all shapes and sizes, from stones and pebbles, down to the finest powder; and, on account of their extreme irregularity of shape, they cannot lie so close to one another as to prevent there being passages between them, owing to which circumstance soil in the mass is always more or less _porous_. If, however, we proceed to examine one of the smallest particles of which soil is made up, we shall find that even this is not always solid, but is much more frequently porous, like soil in the mass. A considerable proportion of this finely-divided part of soil, _the impalpable matter_ as it is generally called, is found, by the aid of the microscope, to consist of _broken-down vegetable tissue_, so that when a small portion of the finest dust from a garden or field is placed under the microscope, we have exhibited