1835.] Scientific Intelligence. 469 



of their perihelia nor their ascending nodes regular. The times of 

 their perihelia are also irregular. These are 



January 14 



February 10 



March 8 



April 10 



May 9 



June 11 



July 10 



August 8 



September 15 



October 11 



November J8 



December 13 



137 



The number of those whose course is direct is . 



Retrogade 



137 



If we assume that there are 30 comets in the orbit of Mercury, 

 and no more, (but assuredly there are more ; these 30 have been ob- 

 served), then within the orbit of Herschel there will be above 

 3,000,000 of comets, or 7,000,000 within the solar system. 



Note. — Olbers is of opinion that people in general will allow the 

 comet of this year to pass without notice, in consequence of the poor 

 supply of light. The following table of its course is taken from a 

 short paper by Arago, in the Annuaire for this year. By means of 

 it the track of the comet may be studied on the celestial globe, by 

 those who are not familiar with the geography of the heavens, and 

 their knowledge thus acquired may be applied to the real objects. 

 The comet will be found 



near '( in the Bull 

 between the Twins and Auriga 

 in Auriga (the charioteer) 

 in Lynx 

 in the Great Bear 



in Bootes 



in the Crown 



between Hercules and the Serpent 



in Ophiucus 



near v of Ophiucus 

 in Scorpio near Antares 

 Mr. Wheatstonc on Speaking Machine*. Sth Mai/. — Mr. 

 Wheatstone gave an account of the different attempts which have 

 been made to invent speaking machines, from the time when the 

 oracular responses were delivered at Delphi, through the period 

 when a speaking head was exhibited by the Pope towards the end of 

 the 10th century, and others afterwards, by Roger Bacon and Alber- 

 tus Magnus, with the impositions which were practised upon the 

 credulous, to the present time, when the principle of a speaking 

 instrument has been developed by Mr. Willis. Van Helmont was 



