1st. _Water or moisture._--This must be estimated, because it is so variable, and a knowledge of its quantity is needful, if we will compare together different samples. A weighed amount of the peat is dried for this purpose at 212° F., as long as it suffers loss. 2d. The _proportions of organic matter and ash_ are ascertained by carefully burning a weighed sample of the peat. By this trial we distinguish between peat with 2 to 10 _per cent._ of ash and peaty soil, or mud, containing but a few _per cent._ of organic matter. This experiment may be made in a rough way, but with sufficient accuracy for common purposes, by burning a few lbs. or ozs. of peat upon a piece of sheet iron, or in a sauce pan, and noting the loss, which includes both _water_ and _organic matter_. 3d. As further regards the organic matters, we ascertain _the extent to which the peaty decomposition has taken place_ by boiling with dilute solution of carbonate of soda. This solvent separates the humic and ulmic acids from the undecomposed vegetable fibers. For practical purposes this treatment with carbonate of soda may be dispensed with, since the amount of undecomposed fiber is gathered with sufficient accuracy from careful inspection of the peat. Special examination of the organic acids is of no consequence in the present state of our knowledge. 4th. The _proportion of nitrogen_ is of the first importance to be ascertained. In examinations of 30 samples of peat, I have found the content of nitrogen to range from 0.4 to 2.9 _per cent._, the richest containing seven times as much as the poorest. It is practically a matter of great moment whether, for example, a Peruvian guano contains 16 _per cent._ of nitrogen as it should, or but one-seventh that amount, as it may when grossly adulterated. In the same sense, it is important before making a heavy outlay in excavating and composting peat, to know whether (as regards nitrogen) it belongs to the poorer or richer sorts. This can only be done by the complicated methods known to the chemist. 5th. The estimation of _ammonia_ (actual or ready-formed,) is a matter of scientific interest, but subordinate in a practical point of view. 6th. _Nitric acid_ and _nitrates_ can scarcely exist in peat except where it is well exposed to the air, in a merely moist but not wet state. Their estimation in composts is of great interest, though troublesome to execute. 7th. As regards the ash, its red color indicates _iron_. Pouring hydrochloric acid upon it, causes effervescence in the presence of _carbonate of lime_. This compound, in most cases, has been formed in the burning, from humate and other organic salts of lime. _Sand_, or _clay_, being insoluble in the acid, remains, and may be readily estimated.