DEAR SIR,--I have received with great pleasure your favor on the subject of the steam engine. Though deterred by the complexity of that hitherto known, from making myself minutely acquainted with it, yet I am sufficiently acquainted with it to be sensible of the superior simplicity of yours, and its superior economy. I particularly thank you for the permission to communicate it to the Philosophical Society; and though there will not be another session before I leave town, yet I have taken care, by putting it into the hands of one of the Vice Presidents to-day, to have it presented at the next meeting. I lament the not receiving it a fortnight sooner, that it might have been inserted in a volume now closed, and to be published in a few days, before it would be possible for this engraving to be ready. There is one object to which I have often wished a steam engine could be adopted. You know how desirable it is both in town and country to be able to have large reservoirs of water on the top of our houses, not only for use (by pipes) in the apartments, but as a resource against fire. This last is most especially a desideratum in the country. We might indeed have water carried from time to time in buckets to cisterns on the top of the house, but this is troublesome, and therefore we never do it,--consequently are without resource when a fire happens. Could any agent be employed which would be little or no additional expense or trouble except the first purchase, it would be done. Every family has such an agent, its kitchen fire. It is small indeed, but if its small but constant action could be accumulated so as to give a stroke from time to time which might throw ever so small a quantity of water from the bottom of a well to the top of the house (say one hundred feet), it would furnish more than would waste by evaporation, or be used by the family. I know nobody who must better know the value of such a machine than yourself, nor more equal to the invention of it, and especially with your familiarity with the subject. I have imagined that the iron back of the chimney might be a cistern for holding the water, which should supply steam and would be constantly kept in a boiling state by the ordinary fire. I wish the subject may appear as interesting to you as it does to me, it would then engage your attention, and we might hope this desideratum would be supplied.