3. They shall have the charge, under the direction of the Council, of printing the Memoirs of the Society and of correcting the press. SECT. XIII. Of the Society's Property. An inventory of the furniture and other articles in the Meeting Room of the Society, shall be made every year. Catalogues of the Library, Collections in Natural History, &c. shall also be made for the use of the Members of the Society. SECT. XIV. Of Donations. Every person who shall contribute to the Collection or Library of the Society, shall be recorded as a benefactor, his name shall be read at the annual general Meeting, and shall be inserted in the next succeeding volume of the Society's Memoirs. 1. All communications, presents, &c. shall be sent to one of the Secretaries, if not personally presented by a Member at a meeting of the Society. 2. The author of any communication, if a Member, shall have the liberty of reading his own paper. ON Isometrical Perspective: by Professor FARISH. II. On certain remarkable Instances of deviation from Newton's Scale in the Tints developed by Crystals, with one Axis of Double Refrac- tion, on exposure to Polarized Light: by Mr. HERSCHEL...... III. On the Rotation impressed by Plates of Rock Crystal on the Planes of Polarization of the Rays of Light, as connected with certain pecu- liarities in its Crystallization: by Mr. HERSCHEL.. IV. On the Chemical Constituents of the Purple Precipitate of Cassius: by VII. On the Physical Structure of those Formations which are immediately associated with the Primitive Ridge of Devonshire and Cornwall: XI. On a remarkable deposit of Natron found in cavities in the Tower of ADVERTISEMENT. THE Society as a body is not to be considered responsible for any facts and opinions advanced in the several Papers, which must rest entirely on the credit of their respective Authors. N [Read February 21, and March 6, 1820.] In the Course of Lectures which I deliver in the University of Cambridge, I exhibit models of almost all the more important machines which are in use in the manufactures of Britain. The number of these is so large, that had each of them been permanent and separate, on a scale requisite to make them work, and to explain them to my audience, I should, independently of other objections, have found it difficult to have procured a warehouse large enough to contain them. I procured therefore an apparatus, consisting of what may be called a system of the first principles of machinery; that is, the separate parts, of which machines consist. These are made chiefly of metal, so strong, that they may be sufficient to perform even heavy work and so adapted to each other, that they may be put together at pleasure, in every form, which the particular occasion requires. Those parts are various; such as, loose brass wheels, the teeth of which, all fit into one another: axes, of various lengths, on any part of which the wheel required may be fixed: bars, clamps, and frames; and whatever else might be necessary to build up the particular machines which are wanted for one Lecture. These A |