CONTENTS. 
iii 
Art. XVL Description of a Teinoscope for altering the Lineal 
Proportions of Objects; with Obseryations on 
Professor Amici’s Memoir on Telescopes without 
Lenses. By David Brewster, LL. D. F.R.S.L. 
&. Sec. R. S. Edin. - - 334? 
XVII. Description of the Slide of Alpnach. By the late 
John Playfair, Esq. Professor of Natural Phi- 
losophy in the University of Edinburgh, & Sec. 
R. S. E. With Notes and Observations, 338 
XVIII. Account of Meteorological Observations made in 
N. America by Dr Holyoke and Prof. Dewey, 34?9 
XIX. Account of Natur^ Ice-Houses in Connecticut. By 
Benjamin Silliman, Professor of Mineralogy in 
Yale College, - - - ' 353 
XX. Description of a New and Portable ^Ethrioscope. 
By John Murray, Esq. F. L. S., M. W. S., and 
Lecturer on Chemistry, &c. - - 356 
XXL Description of a Copper Battle-Axe found in Ratho 
Bog, and now in the possession of Andrew Wad- 
dell, Esq. F. R. S. E. - - 357 
XXII. Meteorological Observations made at the Radcliffe 
Observatory, Oxford, in the years 1816, 1817^ 
1818, 1819^ 1820, 1821. Communicated by the 
Rev. A. Robertson, F. R. S. Savilian Professor 
^ of Astronomy at Oxford, - - 359 
XXIII. Notice respecting Mr Barlow’s New Discoveries 
on the Magnetism of Red Hot Iron, &c. 360 
XXIV. Practical Rules for the Determination of the Radii 
of a Double Achromatic Object-glass. By J. F. W. 
Herschel, Esq. F. R. S. L. & E. &c. - S6l 
XXV. Proceedings of the Royal Society of Edinburgh, 370 
XXVI. Proceedings of the Wernerian Nat. Hist. Society, 373 
XXVII. Proceedings of the Cambridge Philosophical Society, 374? 
XXVIII. Scientific Intelligence, - - 378 
I. natural philosophy. 
Astronomy. 1. Comet of 1819, that seems to have passed over 
the Sun, - - _ . 378 
Optics. 2. Mr Herschel’s Experiments on Plagiedral Quartz. 
3. New Property of the Ordinary Ray of Crystals with two 
Axes. 4. Singular Effect of Heat on the Colouring Matter 
of Ruby, - ... 379 
Electricity. 5. Singular Effect of Lightning at Geneva, ib. 
Meteorology. 6. Mr Bowditch on the Meteor of Nov. 181 9 . 
7. Remarkable Aurora Borealis seen in Scotland. 8. Me- 
