Intelligence and Miscellaneous Articles. 381 



'o 



rhomb of the loxodrome is measured by the constant intercepted 

 arc of the equator on the first sphere. 



4. Conversely, if an equal sphere be described about the pole of 

 the loxodrome, and the loxodrome he stereographically projected 

 upon it, then the projection is the spherical logarithmic, whose con- 

 stant subtangent measures the angle of the rhomb in the projected 

 loxodrome. 



At the close of his paper Mr. Davies announces that another 

 system of coordinates, having the same relation to the plane-rectan- 

 gular system that the system he has already treated of has to the 

 plane polar system, will be discussed in No. 25 of Leybourn's Mathe- 

 matical Repository, and in the subsequent Numbers of that work. 



LXII. Intelligence and Miscellaneous Articles. 



ANALYSES OF VEGETABLE SUBSTANCES. BY M. PELLETIER. 



[Continued from p. 313.] 

 f^ARMINE.— This is the colouring principle of cochineal, and was 

 first obtained in a separate state by Pelletier and Caventou, in 

 1808. Carmine, procured by the process described by these authors 

 in their original paper, was subjected to analysis after being dried in 

 vacuo, and at a moderate heat, to deprive it of all traces of alcohol 

 and aether. Its composition was determined by burning with per- 

 oxide of copper. It yielded 



by direct Atomic Calculated 



Analysis. Composition. Results. 



Carbon 49-33 16 49-43 



Hydrogen 6'66 .... 26 .... 665 



Azote 3-56 .... 1 .... 3-57 



Oxygen 40-45 10 40*42 



M. Pelletier expresses, however, some doubt as to the true com- 

 position of carmine, and thinks it possible that the specimen ana- 

 lysed contained some water. 



Chlorophylle. — This name was given by M. Pelletier to the sub- 

 stance from which the colour of the leaves and young stalks of ve- 

 getables appeared to be derived, and which was formerly called the 

 green matter of vegetables, green resin, &c. Later researches have 

 however convinced M. Pelletier that wax enters into the composi- 

 tion of chlorophylle, which, however, does not entirely consist of it. 

 This wax may be obtained colourless and friable when it is sepa- 

 rated from the green oil with which it is combined in the green 

 matter of leaves ; he has not however yet ascertained whether the 

 green colour is essential to the oil, or whether it is derived from a 

 green substance which it holds in solution. For the reasons above 

 stated M. Pelletier has not given any analysis of chlorophylle. 



Olivile. — This is a peculiar vegetable product discovered by M. 

 Pelletier in 1816, in a concrete juice which exudes from the trunks 

 of olive trees in the most southern parts of Italy* It was known 

 to the ancients, and employed by them as an application to wounds. 



