is desirable to use far more than the chemical equivalents, or the experiments don’t succeed.  I perceive that you intend to use guano next year, and that you intend to use it along with the seed.  I trust it will not be sowed in contact with either the seed or the quicklime, which you proposed to use in some of your land.  The best time I have found for applying guano is in wet weather, just when vegetation is making a start in the spring—­say the last week in March, or the first week in April—­as I fear a large part of the soluble portion of it would be washed away by the rains of winter.  It is true we have had none this winter, but when shall we have such another?  Did you ever use woollen rags as manure?  They ought to be excellent, as they are almost all albumen, and are, I fancy, to be had at a very moderate price, not far from you.  Can you inform me what it is that causes the land to be clover-sick?  If it is the abstraction of something from the soil, what is that something?  Sir Humphrey Davy said that a dressing of gypsum would prevent it; but clover does not succeed here (even when dressed with gypsum), if sowed every four years.  One reason why I think so small a quantity of manure will not succeed, is based on the theory of excrementitious secretion.  Decandolle proved that this secretion took place, but he did not succeed in proving that it poisoned the land for a similar crop.  I can only reason from analogy, and it does not follow that an analogy drawn from animal life will hold good when applied to plants; but if we were to feed an animal with pure gluten and pure starch, with the proper quantity of phosphates, &c., are we to suppose it would have no excrements?  Let this be applied to plants:  are we to suppose that the plant assimilates all that is absorbed by its roots and leaves?  When that which is absorbed is what would enter into the composition of the plant, is it not more rational to suppose that the inorganic and gaseous constituents only combine in fixed proportions, and that although the plant may absorb a much larger proportion of one than is required, the surplus is discharged excrementitiously, and perhaps may be unfitted for entering into the plant until it has undergone a decomposition?  In conclusion, I trust you will pardon my frankness in so boldly canvassing your opinions; but it is in this collision of opinion that the truth will be elicited, and if I judge you aright, it is that you wish to discover whether it harmonizes with your preconceived notions or not.

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LOW MOOR, 1st May, 1845.

HENRY BRIGGS, ESQ.