37 



vacuum-tube inserted about 2 inches apart, I obtained a stratified 

 discharge similar to that from an induction coil. 



The experiment was repeated with 400 series of Grove's nitric 

 acid battery. In this case distinct sparks between two copper discs 

 were obtained, and the luminous layers were shown in a peculiar and 

 striking manner, thus proving that the induction coil is not necessary 

 for the production of the striae, as in most of the experiments the 

 only interruption of the battery circuit was through the vacuum- 

 tube. 



I had another tube prepared, substituting for metallic points balls 

 of gas-carbon. At first the stratified discharge was obtained as before, 

 while little or no chemical action took place in the battery ; on heating 

 the potassa, the character of the stratifications gradually changed, and 

 suddenly a remarkably brilliant white discharge, also stratified, was 

 observed ; intense chemical action was at the same time perceptibly 

 taking place in the battery, and on breaking the circuit, the usual vivid 

 electrical flame-discharge was developed at the point of disruption. 



The continuation of these experiments will necessarily occupy much 

 time, involving, as they do, the charging of so extended a series of 

 the nitric acid battery, and with the requisite care necessary for 

 the proper insulation of each cell ; other phenomena were observed 

 which require further verification, but I hope that after the recess the 

 result which I hope to obtain may be of sufficient interest to form the 

 subject of a future communication. 



VII. "Note on the Transmission of Radiant Heat through 

 Gaseous Bodies." By JOHN TYNDALL, Ph.D., F.R.S. &c. 

 Received May 26, 1859. 



Before the Royal Society terminates its present session, I am 

 anxious to state the nature and some of the results of an investiga- 

 tion in which I am now engaged. 



With the exception of the celebrated memoir of M. Pouillet on Solar 

 Radiation through the atmosphere, nothing, so far as I am aware, 

 has been published on the transmission of radiant heat through 

 gaseous bodies. We know nothing of the effect even of air upon 

 heat radiated from terrestrial sources. 



