The discharge channel of any underground waters likely to disturb the foundations should be discovered, and when there are adjacent hills, by tracing their dampest part the probable direction of the surface flow may become known. Inquiry should be made to find out whether any borings have been made over the site in order to determine if the “boils” have been artificially created or are natural blow-wells, in which the water rises over the top and can, perhaps, be led away by gravitation. It is advisable to fill every bore-hole with Portland cement mortar before any excavation is commenced, or they will burst out when the surrounding ground is disturbed. Bags containing shot have been used to help to close a hole, but a preferable method is to insert a pipe down the bore, it having been previously cleared of all dirt; and to fill it with neat Portland cement mortar, the tube being raised as the hole is filled. Such a method, although successful with small holes, is useless in the case of “blows” of the ordinary size. A permanent shaft or cylinder is then necessary. With regard to the treatment of “boils” in foundations, when in the possession of the information hereinbefore named it may indicate a remedy either for “boils” in which the cause of disturbance is at a considerable depth and the head and fall of water moderately large, or when the agitation is merely superficial, which may result from the range of the tidal waters or the want of surface drainage. When a “boil” is of the first order, it is useless attempting to simply stop it by force and prevent the issue of water, as such a method of procedure would result in merely diverting the disturbance, and in addition leave a weak place in the foundations; however, if many “boils” appear, and the disintegrating agency of the water is removed either by conducting or diverting the flow from the site, they can then be filled, and it should be simultaneously effected, or any mere exudation in the whole of the “boils” may become increased in one or two to a flow sufficient to cause a slip or instability, and any concentration of the discharge may produce movement of the ground. Small springs or “boils” have been sufficiently arrested by depositing clay over them, excavating it, and putting in the foundations very promptly and before the “boil” burst out again; such treatment, however, may lead to the backing of a wall becoming saturated and the water being dammed up: on the other hand, the “boil” may be sealed and the water flow away in the original underground channels; also when a “boil” is tapped it may induce an increased flow of the underground waters, for they will find the course of least resistance; and should they reach a fine sand stratum will filter through and set it in motion, provided the head is sufficient to overcome friction; and the support rendered to any overlying stratum will therefore be destroyed.