150 Royal Society. 



limpid and perfectly fluid (incorpusculated), and almost always the 

 seat of the colour ; the latter existing as a substance dissolved in 

 the fluid, while in no instance does colour develope itself in the 

 chylo-aqueous fluid. 



The paper then shows, that at the point where the chylo-aqueous 

 system disappears, namely at the Myriapods, the true blood becomes 

 the vehicle of tlie corpuscles. 



And lastly, the author adduces a great variety of observations in 

 confirmation of the statement, that throughout the whole Molluscan 

 series without exception, coinciding with his " single-Jluid series," 

 the fluids are richly charged with corpuscles. 



The paper is accompanied by numerous illustrations, displaying 

 the characters of the morphotic elements of the circulating fluids of 

 the Invertebrata. 



Anril 1. — A paper was also read, entitled, " On the Electro-che- 

 mical Polarity of Gases." By W. R. Grove, Esq., M.A., F.R.S., &c.- 



The author refers to the experiments of Faraday on dielectric 

 induction, to those of Gassiot on the increase of electrical effects of 

 tension, according as the chemical intensities of a voltaic battery 

 are increased, and to other results, which, though supporting the 

 ^dew of a physico-polar state of gaseous substances intervening be- 

 tween oppositely electrified surfaces, have not hitherto shown any 

 change in the arrangement of the gaseous particles dependent upon 

 their chemical characteristics. 



The electric or voltaic disruptive discharge has hitherto presented 

 only one phenomenon which ofl'ers any analogy to electrolysis, viz. 

 that observed by Mr. Gassiot and others, of the positive terminal 

 being more intensely heated than the negative, when the voltaic 

 discharge passes between metals. With the voltaic arc the eff"ects 

 of heat and the destruction of the terminals so interfere with any 

 eflfects properly due to the transmission of the electric current, that 

 it is next to impossible to eliminate the latter ; on the other hand, 

 with the electric spark from an ordinary machine, the quantity of 

 matter acted on is too minute to give satisfactory evidence of the 

 changes taking place. Mr. Grove sought an intermediate degree 

 of electrical action, and by the aid of an apparatus of Ruhmkorf for 

 producing a powerful secondary current, the results detailed in this 

 paper were mainly obtained. 



A polished silver plate is laid on the pump plate of a good air- 

 pump, and a metallic point is attached to the rod passing through a 

 collar of leathers at the top of the receiver, the point being adjusted 

 at from one-eighth to one-fourth of an inch distance from the plate. 

 Caustic potash is kept suspended in the receiver, and a mixture of 

 oxygen and hydrogen, or atmospheric air and hydrogen, allowed to 

 enter it, and then attenuated until the barometer stands at half an 

 inch ; the discharges from the secondary coil are now made to pass 

 between the point and the plate, when if the latter be positive it is 

 oxidated, if negative the spot of oxide is reduced. 



If there be excess of oxygen and little or no hydrogen, oxidation 

 takes place, whether the plate be positive or negative, though in 



