N. B. I have not, upon overlooking what I have above written, been so particular in my objections to your proposed alterations as may be agreeable and will ask for a little of your patience. See how the alteration of the wheels on the connecting rod by being smaller will operate. They will most certainly shorten the stroke of the engine. This therefore cannot take place unless we alter the wheels round which they move accordingly, which may be done. At the same time in doing it we shall be obliged to lengthen the spindle of the horizontal wheels and disturb the wooden work the whole of which will be attended with considerable expense and require a second alteration when we come to operate with power equal to what those wheels will require, and indeed, why should we go to any expense in alterations which can do us no service; as I clearly saw from actual experiment that about 1400 pounds will be necessary to be applied directly to the wheels independent of friction, which is equal to an engine of 24 inches Cylinder. An Engine of this size I find has 5424 pounds power independent of the friction of the machine and I think power enough for the air pumps (perhaps something more.) This I cannot however ascertain until I get a barometer and try our present engine, which I believe perfect. I was about trying the power by weights but found difficulties which I have not yet been able to get over, as her power is equal both ways, and to bring the weight only to the connecting rod would tear everything to pieces. Yours, &c. N. J. ROOSEVELT. A plan of my substitute which may not be quite correct, as I do not understand anything of drawing. N. J. R.[3] N. J. ROOSEVELT TO R. R. LIVINGSTON. Second River, _Sept. 10th, 1798_. Dear Sir,