Reports and Proceedings — Geological Society of London. 89 



when mixed with, air are first of all stated; also tlie influence, of 

 dust on the explosibility. Then follows a historical summary of 

 methods of gas-testing used in coal-mines, more particularly by 

 " test-flame " and " flame-cap," whether with oils, alcohol, or 

 hydrogen. The hydrogen-flarae, however, is considered to give 

 the best results. It has, indeed, been found practicable to introduce 

 it into an oil safety-lamp, so as to supply a " standai'd flame " and 

 its distinct " flame-cap " ; and to supply a light even when the oil- 

 wick fails to burn. It is specially adoptable for testing the coal- 

 bunkers on board ship, which are so often the source of destructive 

 fires and explosions. Test-chambers and other apparatus for ex- 

 perimenting with flame-tests on known and unknown mixtures of 

 air and gases are fully explained and illustrated. 



Amongst the combustible gases carbonic acid is here included ; 

 and Dr. Haldane's researches on the poisonous pi-operties and 

 the detection of this gas (carbon-raonoxide) are summarized 

 (pp. 130-145). Carbonic acid gas (carbon-dioxide) is also dealt 

 with, as often present with combustible gases, and as being a product 

 of their burning or explosion. 



A very important chapter follows on the detection and measure- 

 ment of the vapour of petroleum in the air (by B. Redwood), 

 pp. 168-197 ; particularly in the steamers carrying petroleum in 

 tanks, and in the holds of vessels carrying or that have carried 

 casks of petroleum. 



A classified bibliography of papers relating to the subject of this 

 useful book is added (pp. 198-200), and an index is appended. 



T. E. J. 



K,E!JP0:RTS J^IsTlD IFS-OGJBSXDII^a-S- 



Geological Society of London. 



I._December 2, 1896.— Dr. Henry Hicks, F.R.S., President, in 

 the Chair. The following communications were read : — 



1. "Another Possible Cause of the Glacial Epoch." By Professor 

 Edward Hull, LL.D., F.R.S., F.G.S. 



In the introductory portion of the paper the author gives an 

 account of the submarine topography of the area east of North 

 America, and summarizes Dr. J. W. Spencer's work upon a sub- 

 merged Antillean continent ; he then deals with the efi"ects which 

 would be produced upon the Gulf Stream by the uprising of this 

 continent in the Glacial Period, and maintains that, as the current 

 could not pass into the Gulf of Mexico (being debarred by a coast 

 of high continental land), it would flow directly northwards into 

 the North Atlantic, and thereby be deprived of about 10° (Fahr.) 

 of heat : the effects of which may be practically illustrated by sup- 

 posing the isothermal line of 32° to take the place of that of 42° 

 in the northern hemisphere. He argues that the increased snowfall 

 which would thus be caused over certain areas would tend to intensify 

 the cold through all the adjoining tracts. 



To the effects produced in this way must be added those due to 



