Our last earthquake experience showed that buildings erected upon made ground are not safe, unless the lot has been piled, and piling is an expensive process. One of the buildings on California street, near Sansome, which was badly injured by the earthquake, is about to be replaced by a more substantial structure which is being built upon piles. The lot has a frontage of 100 feet by a depth of 89 feet, and the piling of it cost $20,000. This tax is entailed upon builders upon water lots only, and even after such lots are thus provided with an artificial foundation, it is open to doubt whether a building is anything like as safe upon them in case of earthquakes, as it would be upon natural foundation of solid ground. Rents have rather fallen than advanced in the city slip and water lots region, while the imperative necessity of piling makes buildings much more expensive than before; consequently a fair rate of interest cannot be expected, in the shape of rents at the city front. Owners, whose buildings have not a foundation of piles cannot go abroad, trusting with certainty to their property renting; for while they are away, a shake may come which will injure their buildings and frighten tenants out of them. Ever since the last earthquake, lots upon "made ground" have been in disfavor, with no prospect of a change.