When the coffin is not laid in contact with the soil, but entombed in a vault or walled grave, the occupied space is covered by a stone cemented down, air-tight, upon a ledge in the wall, and the raising of which is for ever forbidden. The entombment may also be made by an air-tight surrounding of concrete. The best practice of vault burial is to place some charcoal or disinfectant along with the coffin, so that no foul gas shall escape should reopening be necessary. When old vaults underneath churches are reported upon and found inimical to public health, the churchwardens can be compelled to remove the contents elsewhere, and disinfect the vaults, charging the poor-rates with the expenses. No interment is now allowed under any new place of worship, except with the authority of the Secretary of State. During the ten years, too, which followed the passing of the Burial Acts in 1852, more than one hundred church vaults in the metropolis were disinfected and sealed up. Cemeteries, and not churchyards, are now the chosen sites for interments. These cemeteries are permitted to be located upon any piece of ground, provided that the usual restrictions are not set at naught.[100] A well-chosen cemetery[101] is one whose soil is dry, close, and yet porous, permitting the rain and its accompanying air to reach a reasonable depth, and so expedite decay. The formation is also well covered with vegetable mould, which assists in neutralising any hurtful emanations and encourages the growth of shrubs. The subsoil is also of such a kind as to need no underdraining, and such as will prevent the water lodging in any grave or vault.[102] It will also stand exposed to the north or north-east winds, which are dry, and which do not hold the putrefactive gases in solution, like the moist south or south-westerly winds. [100] The Congress of Hygiene at Brussels recommended an intervening space of 400 mètres between a cemetery and any habitation. [101] The Greek word cemetery means a sleeping-place, and the idea of rest would be far better conveyed if only ashes were laid there, as no further atomical change would be possible. [102] In the Tooting cemetery enquiry, November 1874, it was proved that although the subsoil required draining, the merest surface drainage had been resorted to. The Burial Board admitted that in one instance a coffin had been deposited in a grave with water in it sufficient to cover it.