Sir, - I have noticed with interest the several communications upon heating, and have felt a strong desire to put in a word; but have been deterred by the fact that I was only an amateur.

Mr. Park's letter, however, confirming, as it does, the opinion I formed a his place last year, emboldens me to say my say in the matter. The chief objection to the common hot-water, and also to steam apparatus, I take to be, an insufficient range in the amount of heat that can be evolved. This, I think, is overcome by a-high-pressure hot-water apparatus, as per sketch. This can be kept in action with the water only blood warm, and in a few minutes can be run up to, and maintained at, any required point, up to say a hundred pounds pressure, by simply weighting the valves, and firing up. And, by the way, I think "economy in fuel" is too much harped upon ; yon can not get something out of nothing. If you want heat you must burn fuel; and Mr. Park, instead of growling at his furnace for using up so much coal, should thank his stars that it had the capacity to do it.

Scale one inch to the foot.

a Regulating valve.

b Feed tank.

c Check valve on feed pipe.

Furnace of 1/4 inch iron.

Water space 1 1/4 inch. Circulating pipes, 1 1/2 to 2 1/2 inch, Supply and overflow pipes,1/4 inch.

Brooklyn.

[This is another "Brooklyn," distinct from the other. We should like you to have said something about the probability of "blowing up" with a high-pressure boiler; the amount of danger in the one you propose; how to avoid it, etc. Will you not do so, and go a little more into detail with regard to the capacity of your boiler, etc.? People do grumble about burning coal; sometimes unjustly, but oftentimes with good reason. What we want, is something in the way of heat for what we do burn. - Ed].

Hartford, Conn., December 14, 1860.