CONTENTS. 
Ill 
Art. XXTIl. On the Opals of Hungary. By J. S. Beudant, 
Chevalier of the Legion of Honour, Member 
of the Wernerian Society, &c. - 332 
XXIV. On the Alloys of Steel. By J. Stodart, Esq. 
F. R. S.; and Mr Faraday, Chemical Assist- 
ant to the Royal Institution, - 350 
XXV. History of Mechanical Inventions and Processes 
in the Arts, 
1. The Rev. Mr Cecil’s Machine, in which Hydrogen 
Gas is the Moving Power, - - 364 
2. Account of Mr Bald’s Steam Passage-Boat for the 
Alloa Ferry, . - , 365 
3. Mr Harford’s Improvements on Puddling Furnaces, 369 
4. Description of a Ductilimetre for comparing the duc- 
tility of different Metals. By M. Rcgnier, 370 
5. On the Fabrication of Artificial Pastes in Imitation 
of Precious Stones. By M. Doualt Wieland, 370 
6. Description of a New Blowing-Machine, - 373 
7. Account of Improvements made on Steam-Packets, 
and other Vessels. By David Gordon, Esq. ib. 
8. Notice respecting the Escapement of M. Jurgensen, 375 
XXVI. Geological Thermometer, shewing the Opinions 
attributed to various Geologists with respect 
to the Origin of Rocks, - - 376 
XXVII. Celestial Phenomena, from October 1. 1822 to Ja- 
nuary 1. 1823, calculated for the Meridian of 
Edinburgh, Mean Time. By Mr George 
Innes, Aberdeen, - - 377 
XXVIII. Proceedings of the Royal Society of Edinburgh. 
(Continued from p. l65.) - 379 
XXIX. Proceedings of the Wernerian Natural History 
Society. (Continued from p. 1 67 .) - ib. 
XXX. Scientific Intelligence, - - 380 
I. NATURAL PHILOSOPHY. 
Astronomy. 1. On the Solar Nutation. 2. Dr Brinkley's 
Elements of the Comet of 1821. 3. Length of the Pendu- 
lum at Madras. 4. Derangement of the great Mural Circle 
at Greenwich. 5. Curious appearance observed on the 
Moon at the Cape. 6. Comet of 1 822. 7* Account of Rieussec's 
Chronograph for noting small intervals of Time, 380-385 
Meteorology. 8. Depression of the Barometer in England 
on the 25th December 1821. 9* Observations on the Baro- 
meter and Thermometer at Berlin, 25th December 1821. 
10. Singular contrast between thej Winter of 1821-2 in the 
North of Europe and South America, - 385,-386 
