Scientific Intelligence — Astronomy. 1 75 



Mr Whewell gave an account, illustrated by drawings, of the Phenomena 

 of granite veins in Cornwall, especially at Trewavas Head, Polmear Forth, 

 and Wicka Pool. 



November 24, 1828. — The Bishop of Lincoln, the President, in the 

 chair. 



A memoir was read by Professor Airy On the Longitude of the Cambridge 

 Observatory. He observed that differences of longitude, as determined by 

 geodeiical operations, and by differences of sidereal time, do not necessarily 

 coincide. They depend upon different definitions and are useful for dif- 

 ferent purposes. The geodetical longitude of Cambridge Observatory from 

 Greenwich, as proved by the trigonometrical survey, is 24" 6. of time east. 

 But on the 21st, 22d, and 23d of October last, a comparison of the transit 

 clocks at the two places was made by means of six pocket chronometers, 

 carried four times from one place to the other ; and this gave the astrono- 

 mical difference of longitude 23" 54. which Professor Airy considers as the 

 quantity to be used in future. 



A paper was also read by Mr Willis of Caius College, On the Vowel 

 Sounds ; and after the meeting experiments were exhibited illustrative of 

 the doctrines asserted. It appears that the vowel sounds may be produced 

 by means of a loose reed in the order /, e, a, a, o, o, u, by successively con- 

 tracting the aperture of the cavity in front of the reed. It appears also, 

 that by fitting on a tube of gradually increasing length, the sounds pro- 

 duced are, the above series of vowels in a direct order, and the same in an 

 inverse order, with intermediate positions giving no sound; and that this 

 cycle is repeated at equal lengths of the tube. A variety of other in- 

 teresting facts and principles were brought forward. 



Art. XXX.— scientific INTELLIGENCE. 

 I. NATURAL PHILOSOPHY. 



ASTKONOMY. 



1. Observations on Encke's Periodical Comet. — This comet was disco- 

 vered on the 3d October by M. Pons at Florence. Our able countryman, 

 Mr Dunlop, <liscovered it at Makerston, in the observatory of Sir Thomas 

 Brisbane, on the 25th of October, and has observed it diligently since that 

 time. 



2. Ephemeris of Encke's Cotnet continued. 



io«o n- 1,.. A Declination Log. Dist. 



. 1828. Right Ascen. ^^^^^^ froS Earth. 



Nov. 15.3 329° 31' 18°25' 9.6942 



17.3 327 24 17 20 9.6911 



19.3 325 20 16 13 9.6881 



21.3 323 17 15 5 9-6863 



23.3 321 20 »13 57 9.6843 



