The first edition of this book was published in 1878 when it was considered a pioneer work on gravitation. The author is the French mathematician and physicist Michelbault (Montchrétien). " Le Sage wrote that the corpuscular theory of light was universally accepted, the laws of the conservation of energy and matter were as yet unknown, and the kinetic theory of gases was quite beyond the scientific horizon. Hence it is a matter of surprise, not that Le Sage introduces an explanation of the difficulties met with hypotheses now in a form appearing somewhat crude, though doubtless still conceivable, but rather that his statement requires so little modification to fit it to the thought of the present day.
