I have used steam for two winters in my greenhouses, in place of the hot-water system, which had furnished the heat for the previous twelve years; and if my experience will be a help to those who still doubt, I am disposed to add something to the valuable contributionsin your April and May numbers.

I adopted the Exeter Machine Co.'s boiler, for the reason that I knew of its value in heating dwellings, public buildings, etc, in this region, where it meets with unqualified approbation. I am very glad to see that Mr. Evans and Mr. Simpson have found this boiler and the heating by steam as easily understood and managed as I have done, and I am free to say that all who adopt the system of low pressure, with the boiler and plans of piping houses recommended by the experienced workmen of the Exeter Company, will not be disappointed.

The specially valuable point in the sectional boiler is, as Mr. Simpson says, that more sections can be added in case more heat is wanted. Another important feature should be mentioned, and that is, in case of accident from improper management : The sections do not explode, tearing everything to pieces; they simply crack, and you have notice at once by the steam or water oozing out. In such case the cracked section can be removed, the connecting joints plugged, and the heating go on till a new section is ready. With ordinary care, however, such a contingency will not arise, for the sections will never give out if there is sufficient water in the boiler.

My boiler has twenty-four sections, in two batteries of twelve sections each, set over two fire boxes. In moderate weather one fire will make steam fast enough to heat the six houses, equal to 12,000 feet of glass. The second fire is lighted when the weather requires it. It will readily be seen that this plan of two fire boxes is specially valuable in case of accident to the boiler.

Five pounds pressure has proved in my houses to be sufficient to meet the coldest temperature, even at the extreme ends of the houses. Two or three pounds is more often the register of the gauge, and the thermometer in the houses will stand at 6o°. I have never been able with hot water pipes to raise the temperature so high in my largest houses at night as with steam at five pounds and less; hence I do not see the need of fifteen to twenty pounds pressure, which appears to be Mr. Bochman's register (see p. 105 of your April issue).

Some of your correspondents advise the use of large pipes. Under high pressure Mr. Bochman's reasonsmay be good; but for good resultsin warm, as well as cold winter weather, I would prefer four 1-inch or 1 1/4-inch pipes to two 2-inch pipes, the cost of putting up being about the same. I think the large pipes objectionable from the fact that the heat cannot be kept low enough in moderate weather. With four lines, instead of two, the temperature is under better control. I have adopted, as a compromise, this plan : A large main of 2-inch pipe runs the entire length of the house, about twelve inches from the ridge, the gradient line being, say ten inches in the hundred feet, downward toward the extreme end, where branches of smaller pipe lead to the coils and manifolds, as shown by Mr. Evans on pages 102-3. (April number, G. M.) These coils have a like gradient downward to the inner end of the house, and hence the return water is flowing freely in all, and finally drops into the main drip and returns to the boiler.

The entire series of pipes must, of course, at the lowest point be some fifteen inches above the water line in the boiler, thus dispensing with automatic traps, etc.

Here we have a large pipe heating the upper part of the house, and a series of three or more small pipes, which are opened or closed as occasion requires, on the sides. The advantage of this system will be apparent to any one who will look into it. I believe the large pipe near the roof does an important part of the heating, and is a test of the idea suggested in the editorial notes of the G. M., page 107. An all-important requisite is good draft. Burning anthracite coal with a sluggish draft is very expensive. We all know that it can be reduced by dampers; but we must not be content with anything short of a strong upward current when occasion requires.