312 Scientific Intelligence [April, 



The septaria occur either in beds, or casually dispersed through 

 the mass of the great deposit of blue clay which lies above the 

 chalk. The deep cutting for the archway at Highgate Hill, the 

 canal in the Regent's Park, and the clay pits between London 

 and Hackney, exhibit sections of this stratum ; as also do the 

 cliffs at the Isle of Sheppy, and at Southend, on the opposite 

 shore of the Thames. The space between the South Downs and 

 the central chalk ridge of the Isle of Wight is chiefly occupied 

 with the same deposit. Septaria also exist in other beds of slaty 

 clay lower in the series than the chalk. They bear a great 

 analogy also with the balls of argillaceous iron ore, deposited in 

 the shale between certain beds of coal ; and probably these iron- 

 stone balls would answer many of the purposes of the genuine 

 septaria. 



With regard to the latter query of our correspondent, we fear 

 that it will be impossible to prevent either iron or brass wire from 

 being corroded when exposed to a constant alternation of air and 

 of moisture. — Ed. 



IX. Neiv Comet. 



Dr. Olbers, of Bremen, has just discovered a new comet, 

 Nov. 1, at seven p. m. in the west shoulder of Serpentarius, 

 between the stars K and No. 104 of Bode. It was small and 

 very brilliant, particularly in its centre, without a visible nucleus, 

 or tail. It cannot be seen without the telescope. At 7 h 14' its 

 right ascension was 253° 13', its northern declination 9° 14', 

 its course was directed from E. to S. (Quoted from Gazette 

 d'Aix-la-Chapelle, in Journ. Phys. Nov. 1817.) 



X. Chemical Analysis of Pimento. 



M. Braconnot has subjected this substance to an elaborate 

 examination, the result of which is, that it consists of the follow- 

 ing ingredients : 



1 . Fecula 9-0 



2. A very acrid oil 1-9 



3. Waxy matter united to a red colouring principle. 0*9 



4. A peculiar gummy matter 6-0 



5. Animalized matter 5-0 



6. Citrate of potash 6-0 



7. Insoluble residue 67-8 



8. Muriate of potash. "} 



9. Phosphate of potash. 1 3*4 



Loss. J 



100-0 



M. Braconnot has performed some experiments on lichens, 

 and particularly on a species of variolaria, probably the faginea, 

 the constituents of which are stated to be the following ; the 

 particular details are not given, and the analysis is obviously 



