348 



KNOWLEDGE. 



September, 1913. 



there a few megaspores. Some of them grade into a material 

 which is nothing but a black carbonaceous mudstone. The 

 majority of the coals examined are humic coals, composed of 

 the droppings of trees and plants in the form of spores, fruits, 

 leaves, twigs, and sometimes fragments of flattened stems. 

 Mr. Lomax comes to the conclusion, contrary to some recent 

 opinions, that no great quantity of wood enters into the com- 

 position of coal ; and what there is occurs mostly in the form 

 of charcoal or " mother of coal." In the hardest, purest, and 

 brightest coals the material has been reduced to a more or 

 less pulpy state before carbonisation. 



An interesting and important practical application of these 

 results has been made. The author suggests that the micro- 

 scopic examination of a coal-seam may be a good guide as to 

 the inflammability of the dust likely to be given off. Many 

 coals have been shown to be composed largely of the spores 

 of the huge Lycopods of the Carboniferous period, plants 

 whose descendants are the recent Selaginellas and Club- 

 mosses, the spores of which are known to be highly inflam- 

 mable. The spores in the coal have not lost their highly 

 inflammable and explosive nature during their long entombment, 

 and when released in the form of dust during working produce 

 a highly explosive mixture. Many coals, moreover, contain 

 the resinous and inflammable bodies known as Ovalites 

 resinosus. Hence coals rich in megaspores and Ovalites 

 resinosus are likely to give rise to a very explosive dust, and 

 this conclusion is borne out by the microscopic examination 

 of coals which are known to produce such a dust. 



ALLUVIAL FAN FORMATIONS.— In arid regions 

 of high relief, such as the western deserts of North America, 

 there are huge deposits of rock-detritus in the form of confluent 

 or interdigitating alluvial fans. These fans or cones are 

 deposited by occasional violent torrents, and, owing to the 

 diminishing velocity and carrying power of the water towards 

 the lower levels, a more or less regular gradation occurs from 

 large blocks at the upstream point of the fan to fine silt in 

 the playas, or river-bottoms. This material is prevailingly 

 angular, although there may be admixture of rounded pebbles 

 due to the denudation of old conglomerates in the mountains 

 from whence the detritus is derived. When cemented these 

 fan-deposits are called " breccias," in accordance with current 

 usage ; but as A. C. Lawson points out (Bulletin of the 

 Department of Geology, University of California Publi- 

 cations, Vol. VII.), the term "breccia" is so overloaded with 

 meanings that it has no particular connotation suggestive of 

 the kind of rock to which it is applied, or its origin. Hence 

 Dr. Lawson proposes the new term " fanglomerate " — a 

 particularly ugly hybrid — for the deposits described above. 

 He also points out the scarcity of rocks of this kind in the 

 older geological formations, even after making due allowance 

 for possible non-recognition or disguise under other names, 

 and suggests that this may be explained by the supposition 

 that the combination of bold relief and aridity was not common 

 in the geological past. It is further concluded that the period 

 of time from the Quaternary to the present is exceptional in 

 geological history in respect to the coexistence of these two 

 conditions over a large portion of the North American 

 continent. 



METEOROLOGY. 



By William Marriott, F.R.Met.Soc. 



THE "FERNLEY" SELF-RECORDING RAIN 

 GAUGE. — The Southport Meteorological Observatory is 

 considered by meteorologists to be one of the best equipped 

 observatories in this country. When the Royal Meteorological 

 Society held its Provincial Meeting at Southport in May last 

 year, the Fellows had an opportunity of inspecting the 

 Fernley Observatory and the Marshside Anemograph 

 Station, and also of seeing the large collection of instru- 

 ments at work, the great care bestowed upon them, and 

 the remarkably clear and valuable records obtained from 

 them. Mr. Joseph Baxendell, the Borough Meteorologist, in 

 his Report for 1912, describes the " Fernley " self-recording 



rain-gauge, which he has just brought out and added to the 

 equipment of the Observatory. In this he has introduced a 

 new action of siphoning, and also added other improvements. 

 Figure 376 illustrates the working of the instrument. 



The rain collected by an 11-inch deep-rimmed funnel [not 

 shown for want of space] passes through a wide pipe (C) to 

 the cylinder (A), raising the float (B) and a new anti-friction 

 wheels' pen-carrier, until 0-50 inch has fallen, when a cam 

 (K) throws over a rocking-weight shown, and this, by means 

 of a tripping-rod (J), causes the contents of a tilting-bucket 



Figure 376. 

 Plan of the " Fernley " Self - Recording Rain Gauge. 



(H) to be emptied into a water-air-pump (G, F). A i-inch 

 bore copper syphon (D) above the pump, and leading 

 from the side of the rain cylinder (A) to a trap (E), is 

 rapidly exhausted by the water-air-pump and, coming into 

 action full-bore, empties the half inch of rainfall in half a 

 dozen seconds, the pen returning to zero on the chart. The 

 water, escaping through a pipe (M), refills the tilting-bucket 

 (H), which is raised or "righted " not merely by the flush of 

 water, but also by a lever (O) that is actuated by the rocking- 

 weight while the latter is being raised into position (through a 

 pin and lever) by the weight of the descending float (B). A 

 detent (N) locks the rocking-weight until rainfall has caused 

 the pen once more to approach the top of the chart ; the 

 rocking-weight cannot, therefore, be accidently thrown over in 

 the meantime. 



This new rain-gauge, which is made by Messrs. Negretti 

 and Zambra, works in a most satisfactory manner, and will 

 be of great value not only to meteorologists, but also to 

 engineers, surveyors, and all others who require continuous 

 rainfall records of a thoroughly reliable character. 



