552 Intelligence and, Miscellaneous Articles. 



as a carbon-spectrum, but wMch, according to Vogel, have likewise 

 formed the spectrum of comets. Moreover, if it be remembered 

 that the repulsion hi question, in itself, requires from the repelliug 

 body only the conducting quality, and not any free positive or 

 negative electricity, the expectation will not be considered un- 

 warranted that these experiments will be of importance for the 

 electrical theory of the tails of comets and their repulsion — a 

 theory to which several distinguished astronomers have already 

 turned their attention. 



In several tubes even at a pressure of 20 millims. (at which the 

 observations commenced) distinct strata appeared ; and while the 

 rarefaction was then continued the connexion between the number 

 of the strata and the rarefaction could be proved. It came out 

 that, so long as the chemical quality of the luminous gas-columns 

 and all the other circumstances except the density could be taken 

 as unchanged, the number of the strata diminishes in the ratio of the 

 rarefaction, or, in other terms, that the interval from the centre of 

 one bright stratum to that of the next increases proportionately to the 

 rarefaction. This law may be expected to hold good either strictly 

 or at least very approximately ; for it appeared correct so far as 

 our observation extended. The intensity of the current, too, has 

 a great influence upon the number and clearness of the strata ; 

 indeed, by altering it stratified can be changed into imstratified 

 light, and the converse. By further investigations we shall pro- 

 bably obtain data enabling us here also to state a simple normal 

 relation. The conjecture expressed in our first communication on 

 the phenomena in question, that the magnet increases the number 

 of the strata by condensation, is now verified by the observed in- 

 crease of the strata proportionate to the density. 



It was mentioned in our second communication, that when the 

 tube was filled with oxygen the so-called dark space appeared in 

 grey-green light. This nebulous grey-green light we have ob- 

 tained, by the employment of the G-eissler air-pump after filling 

 with oxygen, in the entire Wtillner tube with the sole exception 

 of the capillary part, and found it accompanied by a very vivid 

 brilliance. The observations made on this occasion would agree 

 better with Sarashxs than with Morren's explanation of brightly 

 luminous G-eissler tubes. We must reserve the details for a sub- 

 sequent full communication, as well as those of the experiments 

 of which the chief results have now been described, and also the 

 numerous more or less important collateral phenomena observed, 

 such as — that the grey-green light in oxygen-tubes is neither 

 attracted nor repelled, that on the rarefaction being increased a 

 bright spiral, wound round the positive wire electrode, is developed, 

 that at the tip of this electrode a very bright starlike point makes 

 its appearance on filling the tube with a carbon compound, that 

 the yellow-green light in the glass, which we mentioned in the first 

 communication, constantly accompanies the higher degrees of 

 rarefaction, that in very many cases the so-called dark space is 

 absent, that the current, long continued, has an analyzing effect, 

 &c. — Kaiserliche AJcademie cler Wissenschaften in Wien, math.- 

 naturw. Classe, Oct. 12, 1876. 



