I send you the Candles I have been making; In a little time after they are lighted the smoke and flame separates, the one issuing from one end of the Candle and the other from the other end. I supposed this to be because a quantity of Air enters into the Candle between the Tallow and the flame, and in its passage downwards takes the smoke with it, for if you blow a quantity of air up the Candle, the current will be changed and the Smoke re-ascends and in passing thro’ the flame makes a small flash and a little noise.

But to express the Idea I mean of the smoke aescending more clearly it is this, that the air enters the Candle in the very place where the melted tallow is gelling into the state of flame, and takes it down before the change is compleated, for there appears to me to be two kinds of Smoke, humid matter which never can be flame, and enflameable matter which would be flame if some accident did not prevent the change being compleated and this I suppose to be the case with the descending smoke of the Candle.

As you can compare the Candle with the Lamp, you will have an oppertunity of ascertaining the cause, why it will do in the one and not in the other. When the case of the inflamed part of the wach is close with the edge of the Tin of the Lamp no counter current of Air can enter but as this contact does not take place in the candle a counter Current enters and prevents the in the candles, which illumenates the Lamp. For the passing of the air thro’ the Lamp does not, I imagine, burn the smoke but burn up all the oil into flame, or by its rapidity prevent any part of the Oil flying off in the State of half flame which is smoke.

I do not my Dear Sir offer these reasons to you but to myself, for I have often observed that by finding words for my thoughts I understand my thoughts the better. Thoughts are a kind of mental smoke, which requires words to illuminate them. I am Affeckenately your Obedient Humble servant