From the experiments and observations which have been made with respect to the decomposition of animal bodies that are interred in burying-grounds, it appears that they are, in such situations, subjected to very different laws of decomposition, from those which take place in bodies exposed to the open air. In the former case no danger can attend the operation provided the body be buried at a sufficient depth, and that the grave be not opened before its entire and complete decomposition. The depth of the grave ought to be such that the external air cannot penetrate it; that the juices with which the earth is impregnated may be conveyed to its surface, and that the exhalations, vapours, or gases, which are developed or formed by decomposition, should not be capable of forcing the earthy covering which detains them. The nature of the earth in which the grave is dug, influences all its effects. If the stratum which covers the body be argillaceous, the depth of the grave may be less, as this earth affords with difficulty a passage to any gas or vapour; but, as a general rule it may be admitted, that bodies should be buried at the depth of five feet, to prevent any unpleasant consequences. It is also important to remember that the decomposition of the soft parts, according to _Mr. Petit_, is not terminated until the expiration of three years, in graves of four feet deep; or four years when their depth is six feet. This term, of course, is stated as a medium; it must necessarily vary according to the nature of the soil, and the constitution of the subjects buried in it. A knowledge of these facts ought to lead to a more rational system of interment. We can scarcely expect to see the fulfilment of the wish expressed by Evelyn in his _Sylva_, the establishment of a _Necropolis_ without the walls; but much may be effected by judicious regulations; and the law will uphold any parochial officer in the conscientious discharge of the requisite duties; in certain cases it invests him with a considerable latitude of discretion; thus when a body is brought to be buried “it seemeth to be discretionary in the minister whether the corpse shall be carried into the church or not, and there may be good reason for this, especially in cases of infection.”[164] A curious controversy has lately taken place upon the introduction of iron coffins, and chemists have differed widely upon the subject of their relative durability, when compared with those of wood. Sir _William Scott_ (now Lord _Stowell_) decided, and we think very justly, that under ordinary circumstances the former appear less perishable, and therefore when admitted into burying-grounds, that the parties are to be held liable to extraordinary fees.