Q. My inquiry of October 13, to which you now very kindly reply, was prompted by the fact that in a new building fitted with a copper boiler of the best make, supplied with the safe and vacuum valve of your illustration, the boiler suffered a total collapse when the water company suddenly turned off the water, a few days before the date of my letter. The water company promptly replaced the boiler with a new one, because they neglected to give notice of their intention to turn off the water; but I now desire to learn whether or not such accidents are preventable. I always use the open-end relief-pipe where there is a tank to carry it above, but when you have city water at 45 pounds pressure what do you do?

A. It would seem that your experience justifies our opinion that it is not always safe to rely on safety and vacuum valves on range-boilers. Under the conditions named by you - viz., that you have a public water-service with an average pressure of 45 pounds to the square inch - we should advise you to take this supply to a tank, controlling it by a ball-cock. Then take your supply to the boiler from this tank, returning the hot-water pipe above and over the tank as a relief-pipe. You can then use copper boilers with safety.

The only other plan is to use galvanized-iron boilers. This is cheaper, but not so desirable, although generally done. How your water will be affected by contact with galvanized-iron you can ascertain by trial.