1876.] On the Gaseous State of Matter. 455 



two, an afferent and a motor, just as, in Man, the double function o£ 

 an ordinary spinal nerve is divided in the head between the 5th and 

 7th pairs. And it seems not unlikely that while the " axial cords " 

 (motor nerves) of the arms are derived from the peripheral part of the 

 Crinoidal axis, the " ventral bands " (sensory nerves) are derived from 

 the central part of that axis, which has been shown to be continued, as 

 the " axial prolongation," to the oral ring. 



The Society then adjourned over the Easter Eecess, to Thursday, 

 April 27, 1876. 



April 27, 1876. 

 Dr. J. DALTON HOOKER, C.B., President, in the Chair. 



The Presents received were laid on the table, and thanks ordered for 

 them. 



The Bakerian Lecture, <e On the Gaseous State of Matter/' was 

 delivered by Prof. T. Andrews, LL.D., E.R.S., Vice-President 

 of Queen's College, Belfast. The following is an Ab- 

 stract : — 



After referring to certain modifications in his former method of work- 

 ing at high pressures, the author describes some preliminary experiments 

 which were undertaken to determine the change of capacity in the capil- 

 lary bore of the glass tubes under the pressures employed. Erom these 

 experiments it appears that, on raising the pressure from 5 to 110 atmo- 

 spheres, the capacity was increased for each atmosphere by only 

 0-0000036, and that this change of capacity was chiefly due to com- 

 pression of the internal walls of the glass tube. Another set of experi- 

 ments was made to ascertain whether air or carbonic-acid gas is absorbed 

 at high pressures to any appreciable extent by mercury. Eor the method 

 of operating and other details reference must be made to the original 

 memoir; but the general result is that no absorption whatever takes 

 place, even at pressures of 50 or 100 atmospheres. The pressures are 

 given according to the indications of the air-manometer in the absence 

 of sufficient data (which the author hopes will be soon supplied) for 

 reducing them to true pressures. In the mean time it is probable, from 

 the experiments of Cailletet, that the indications of the air-manometer 

 are almost exact at 200 atmospheres, and for lower pressures do not in 

 any case deviate more than -^ from the true amount. 



In a note which was published last year in the ' Proceedings ' of the 

 Society (No. 163), it was stated that the coefficient of expansion (a) for 

 heat under constant pressure changes in value both with the pressure and 



