Intelligence and Miscellaneous Articles. 335 



to the cap, and only very slowly i£ the pressure be relaxed. The 

 Cartesian diver is now suitable for its ordinary use. 



4. After reiterated repetition of the given procedure, the relaxa- 

 tion of the pressure is useless ; the diver is filled to such a degree 

 that he remains below when the cylinder is turned upside down, 

 the ball resting on the cap, and the tube pointing upwards. 



f). If the cylinder be kept inverted, and the cap be pressed several 

 times iu quick succession, at each interruption of the pressure an 

 air-babble escapes, by which the diver becomes yet more completely 

 filled. At last these means are no longer operative ; a minute aii> 

 bubble remains in the ball, but is of no import for its use as a diver, 

 since the requisite degree of filling has been exceeded. 



After the diver has been taken out of the cylinder, the water 

 which has entered can be removed by a vigorous shaking, of course 

 with the tube downwards. — Poggendorff's Anncden, Ergdnzung, 

 vol. vi. pp. 332, 333. 



RESEARCHES ON THE SPECTRUM OF CHLOROPHYL. 

 BY J. CHAUTARD. 



Conclusions. — I. The spectrum of chloroplryl is characterized by 

 certain bands, among which there is one, in the red, the special 

 properties of which suffice to distinguish the solution. The quali- 

 ties of this band are sensibility, certainty, and generality. 



a. Sensibility, by clear outlines, a fixed position, and a remark- 

 able permanence through a solution so dilute as to contain less 



than jofoo- 



b. Certainty, by the division into two which it undergoes under 

 the influence of the alkalies — a character which belongs neither to 

 the lines of blood, nor to those of bile, nor to those of any other 

 organic fluid. 



c. Generality ; that is to say, this line always appears wherever 

 chlorophyl exists, pure or adulterated. 



II. Chlorophyl exists, in vegetables, in three different states, 

 which can be perfectly recognized in the spectroscope — in leaves 

 newly formed, in adult leaves, and in leaves dead or detached from 

 the vegetable. 



a. In young leaves just expanding, the instability of the elements 

 is very great, and is recognized by the appearance of temporary 

 accidental bands under the action of chlorhyclric acid. 



6. In the second case the same acid gives rise, in the alcoholic 

 solution, to quite another system of bands, which I call permanent 

 accidental bands. 



c. Lastly, In alcoholic solutions of leaves from which the life 

 has disappeared, or in those of fresh chlorophyl which have under- 

 gone a certain amount of change, the permanent accidental bands 

 appear immediately, without the intervention of chlorhydric acid. 



III. As the last consequence of the spectrum-analysis of chlo- 

 rophyl, let us say that this substance, so easy to modify when con- 

 sidered in the physiological point of view, is nevertheless much less 



