504 Mr. A. V. Harcourt. On the Limitation and [June 17, 



We find that the epochs of maximum prominence disturbance in the 

 higher latitudes are widely different from those near the Equator. 

 The latter are closely associated with the epochs of maximum spotted 

 area ; the former occur both N. and S. at intervening times. 



We have then two sets of strongly marked prominence outbursts 

 occurring at intervals of between 3 and 4 years. 



Both sets are represented closely in the Indian pressure curves. 



" On Two Methods for the Limitation and Regulation of Chloro- 

 form when administered as an Anaesthetic." By A. Vernon 

 Harcourt, F.R.S., Eeader in Chemistry at Christ Church, 

 Oxford. Received June 17, — Read June 19, 1902. 



In the ' Transactions of the Chemical Society ' for 1899 an apparatus 

 is described for providing a current of air mixed in any desired pro- 

 portion with chloroform vapour. This apparatus served its purpose in 

 experiments on small animals, but was on too small a scale, and offered 

 too much resistance, to provide the free supply of air at a rate of 4 or 

 5 litres a minute which human respiration requires. 



A gas passing close over the surface of a liquid for a sufficient 

 distance yields to the liquid any part of the gas which is soluble, and 

 takes up from the liquid any part of the liquid which is volatile, as 

 completely as when the gas bubbles through the liquid, while suffering 

 much less resistance to its passage. 



BOXES IN TANK. 



O out in 



Fig. 1. 



Fig. 2 



The apparatus shown here (figs. 1 and 2) consists of two closed boxes 

 made of galvanised iron, a square foot in area and 2 inches in height, 

 with transverse partitions soldered to the top and reaching nearly to the 

 bottom. The partitions are f-inch apart, and extend from one side to 

 within an inch of the opposite side each way alternately. Large 

 stopcocks at the two ends of one of these sides provide inlet and 

 outlet. By this arrangement the gas travels in each box a distance of 

 about 15 feet over the surface of the liquid. 



