We have no account that I know of when the use of fire was not known. We read Gen. iv. 22, that Tubal-cain was an instructor of every artificer in brass and iron, and if reason has any thing to do in this case, we may suppose that the use of fire was known to these mechanics. The date to which this reading belongs, is 3875 years before Christ; but there can be no reasonable doubt but that the use of fire was known long before, and that it was used in the offerings which were made by Cain and Abel. That the discovery of arts and the progress of science have changed man from what he originally was, is no more reasonable, than to suppose that the education which a child acquires by degrees, by the same degrees changes him in respect to his nature. That the arts and sciences serve to improve and extend the human intellects is reasonable enough, but that they add any thing to the natural principles or faculties of man is not conceivable. In fixing the "line of demarcation" between the human nature and the brutal, I will suggest two characteristics which you have noticed by which the distinction may be ascertained. The first is the power or faculty of improving from generation to generation his condition by means of art, and knowing how to advance from one degree of science to another. This I will suppose belongs to man and is peculiar to our race of being. We know of no other animal on earth that has ever improved his condition by the discovery of the arts or an increase of science. The other characteristic is one of your propositions, on which you build your system of doubting, viz. _Superstition_. This is found in no creature but such as is susceptible of religion. Man is the only religious animal, if I may be allowed this form of expression, found on the earth. The progress which man has made in arts and sciences, and the progress he has made in divine or religious knowledge distinguish him from the brutal creation. As in the former he has run into thousands of errors, so in the latter he has wandered in darkness, with now and then a blessed ray of light which improved his mind. When the knowledge of the arts became generally defused by means of the extension of the Roman government, it pleased our blessed Creator to cause the sun of divine light to rise on the Jew and Gentile world. And gave him a covenant of the people, a light to lighten the Gentiles, and the glory of his people Israel. Your opinion that men are seldom made unhappy in consequence of doubting a future existence, may be true in a comparative sense, for I believe there are few in comparison with the whole, who do doubt on this subject. Generally speaking, it is the few, who like the philosopher that rendered himself blind by endeavouring to find out what the sun was composed of, thought there was no sun nor any light, that so far give up a hope of futurity as to be miserable in their belief.