hitelligence and Miscellaneous Articles. 361 



other day the altitudes and azimuths of some of the fundamental 

 stars were observed. The length of the tail is stated to be, on 

 March 6, 42° 55' ; on March 7, 37" 23' ; and, on March 1 7, 32° 47'. 

 It is stated also, that on March 8, the colour of the tail had changed, 

 and become more like the rays of the moon : on the 15th it appeared 

 to be much brighter*. 



XII. Extract from the Translation of a Letter from Professor 

 Bessel, on the Variations of the Proper Motions of Procyon and 

 Sirius. We have already given this communication in full, in our 

 last Number, p. 256. 



LIII. Intelligence and Miscellaneous Articles. 



RECENT COMETS. 



THE Great Comet of 1845, the discovery of which was announced 

 last month, has since been observed in England ; though, owing 

 to its distance from the earth, it had become so faint an object as to es- 

 cape any but a practised eye, aided by the most powerful instruments. 

 Observations made at Ceylon, Bombay, Madras, and other places in 

 the east, have already been received in this country : astronomers are 

 yet expecting the arrival of those made at the Cape of Good Hope, 

 which will doubtlessly furnish data for the satisfactory determination 

 of the elements of its orbit. 



A second telescopic comet was discovered at the Observatory of 

 the Collegio Romano, on the evening of February 25. The posi- 

 tions given by Prof. De Vico are as follows : — 



It was observed by Prof. Schumacher on March 15, at 9^ 55"" 36" 

 (Altona mean time). Its right ascension was then 9^ 29"" 46**3, 

 and its declination -f- 37° 5' 44". 



ON HUMOPINIC ACID. BY M. WOHLER. 



The author gives this name to an acid product analogous to hu- 

 mus, which is produced by the decomposition of narcotina by heat. 



"When narcotina is heated by an oil-bath in a platina vessel, to 

 some degrees above its melting-point, it begins to become coloured, 

 and eventually assumes a deep reddish-brown ; at about 428° it sud- 

 denly swells and disengages a very large quantity of ammoniacal gas, 

 nearly pure. 



The residue solidifies into a very spongy mass, which, after pow- 

 dering, is nearly of a pure brown colour ; it is essentially composed 

 of humopinic acid. 



In order to purify it, the powder must be digested in hydrochloric 

 acid, then washed, and afterwards dissolved in caustic potash, which 



* For other observations of this comet, see the preceding volume, p. 

 341.— Edit. 



