Prof. Voelcker, in a paper published in the Journal of the Royal Agricultural Society, shows pretty conclusively that even the use of the same earth four or five times over, although perfectly successful in accomplishing the chief purpose of deodorization, fails to add to it a sufficient amount of fertilizing matter to make it an available commercial manure. Extended experience in small villages and public institutions seems to confirm his view, that, if the earth-closet is to be adopted by towns, they cannot depend either on farmers buying the manure, or undertaking the labor of supplying and removing it. It is estimated, that, for a population of one hundred thousand persons, there would be required seventy-five tons of earth per day, to say nothing of heavy refuse matters which would be thrown into the closets, and would increase the amount to be removed. Even the quantity required for a village of a few hundred inhabitants, if it were to be brought in and carried out, would entail a considerable cost for handling. I have recently concluded an experiment of six years' duration, the result of which seems to show that this objection to the adoption of the earth-closet system may be set aside, or at least reduced to such proportions as to make it unimportant. In the autumn of 1870 I had brought to my house, where only earth-closets are used, two small cart-loads of garden earth, dried and sifted. This was used repeatedly in the closets; and, when an increased quantity was required, additions were made of sifted anthracite ashes. I estimate that the amount of material now on hand is about two tons. We long since stopped adding to the quantity, finding that the amount was ample to furnish a supply of dry and decomposed material whenever it becomes necessary to refill the reservoirs of the closets. The accumulation under the seats is discharged through simply arranged valves into bricked vaults in the cellar. When these vaults become filled,--about three times in a year,--their contents, which are all thoroughly decomposed, are piled up in a dry and ventilated place with a slight covering of fresh earth to keep down any odor that might arise. After a sufficient interval these heaps are ready for further use, there being no trace, in any portion, of foreign matter nor any appearance or odor differing from that of an unused fresh mixture of earth and ashes. In this way the material has been used over and over again, at least ten times; and there is no indication to the senses of any change in its condition.