This historic book may have numerous typos, missing text or index. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. 1812. Not illustrated. Excerpt: . After having multiplied and varied his experiments in such a manner as to present positive results, M. Lepere, in conjunction with the committee of engineers appointed to examine his experiments, draws the following conclusions: 1st. That the schist of Cherbourg, when strongly calcined and pulverised, forms an excellent mortar when mixed with sour lime.

Sdly. That in order to give precisely the same properties to schist which are possessed by puzzolana and terrass, the former must be calcined in a reverberating, instead of a lime, furnace. No. 50. Description of a very simple and useful Scale, for dividing the vanishing Lines in Perspective. In a Letter from G. Cumberland, Esquire, to Mr. NiCholsok.

* (With an engraving.) SIR--Having been in the habit of drawing for my amusement all my life, and feeling the value of that acquirement, it has been my practice to recommend to others as much of that acquisition as can with vcry DEGREESftttle trouble be attained; I mean the putting into perspective common objects; such as simple landscapes, machines, buildings, and the interior of apartments, manufactories, &c. And where I have had an opportunity to give four or five close lessons, I have generally seen my end obtained to their great satisfaction, without ever showing them the Jesuits, or any other voluminous treatise; books that have hindered more the study of art, than they have ever made artists; for a moment's consideration on this subject will convince any mind, capable of reflection, that, to accomplish the general ends that even moat painters have in view with respect to that art, it is only necessary to know the use of the points of sight and horizontal line. For while men have agreed to avoid bevel lines in all their constructions that are intended for use or ha.