112 NATURAL SCIENCE [August 



London) on behalf of the Railway Company. He reported to the 

 Company that the lignite contained: — 



Moisture . 



Volatile matter .... 

 Fixed carbon .... 



Ash. . 



This record I take it is about the usual result of the analysis of 

 li-nite, and I fear throws very little light on the subject. 



The greater probability seems to be that the gas is derived from 

 either the Purbeck Beds or the Kimmeridge Clays by percolation 

 through the comparatively porous strata above. The Purbeck beds 

 arc known to contain a certain amount of petroleum and bituminous 

 matter, one bed being particularly rich ; but far richer deposits are 

 in the deeper lying Kimmeridge Clays, immediately above which Mi- 

 Henry Willett discovered the gas. 



This matter, however, as also the subsidiary one of the associa- 

 tion of petroleum, is one which can only be determined satisfactorily 

 by means of a deeper boring. The Heathfield borings are much 

 shallower than the bulk of those in North American gas wells, which 

 not uncommonly exceed 1000 feet. The gas which occurs in so 

 many of these American wells is usually the forerunner of a spring 

 of petroleum, and it is possible that the occurrence of gas in large 

 quantities at Heathfield may indicate that there is a larger supply of 

 oil in the petroleum-bearing strata beneath than has been before 

 known to occur at the same horizon in other places. 



Dr Hewitt has also reported to the Railway Company on the 

 gas, which, he states, is composed of three constituents : — 



Marsh Gas . ... 91 "90 



Hydrogen ..... 7 "20 



Nitrogen ...... "90 



100-0 



The first two of the above gases, it may be remarked, are in- 

 flammable, but burn only with a blue non-luminous or comparatively 

 null-luminous flame. Nitrogen is not an inflammable gas. It is 

 clear, therefore, that there is nothing in the analysis which can 

 account for the illuminating power of the natural gas at Heathfield, 

 for it burns with a brilliant yellow flame. The gas when burnt in 

 an ordinary ' batswing ' or ' flat flame ' burner is so luminous that 

 the casual observer would not remark the difference between it and 

 ordinary household gas (although the difference does actually exist). 

 Therefore we must suppose either that some luminous property in 

 the gas did not present itself in the sample taken away by Dr 

 Hewitt, or else that some variation has occurred in the constituents 



