When I was a boy, I thought myself a man. Now that I am a man, I find myself a boy. - Thomas Young

In the astronomical and physical division of the work, will be found a general rule for determining the correction on account of aberration; a comparison of observations on the ; a table of the order of electrical excitation; a chart of the variation of the compass, and of the ; formulae for finding the heat of summer and winter; remarks on the theory of the winds; and a comparative table of all the mechanical properties of a variety of natural bodies.

The historical part of the work can scarcely be called new, but several of the circumstances, which are related, have escaped the notice of former writers on the history of the sciences.

With respect to the mathematical part of optics, the curvature of the images, formed by lenses and mirrors, has been correctly investigated, and the inaccuracy of some former estimations has been demonstrated.