282 



POPULAR SCIENCE MONTHLY. 



principal heiglits. The Delaware, Susque- 

 hanna, and Potomac rise west of the Alle- 

 ghany Front, which they cross, and, continu- 

 ing eastward, traverse the Alleghany ridges 

 and the Blue Ridge to reach the Atlantic. 

 From among the Alleghany ridges of Vir- 

 ginia the James and Roanoke flow through 

 the Blue Ridge eastward. New River, on 

 the contrary, has its source east of the Blue 

 Ridge in North Carolina, and runs north- 

 west across the Blue Ridge, the Alleghany 

 ridges, and the Alleghany Front, to the Ohio. 

 It is thus a general fact that the streams of 

 the Appalachian ranges are not controlled 

 by the mountains. The ridges pursue their 

 courses, and the streams, passing across the 

 ridges, pursue independent courses. The 

 discordance is one of the most marked fea- 

 tures in the topography, and it gives rise to 

 many picturesque water gaps. It is due to 

 the fact that the transverse river channels 

 are older than the valley ridges. Within the 

 valley the brooks and creeks have arranged 

 themselves usually in systems of pairs. 

 Flowing southwest, a brook meets its fellow 

 running northeast, and together they turn 

 southeast or northwest to traverse a ridge. 

 In the valley beyond the ridge they are 

 joined by a pair similar to their own courses 

 before their union. Beyond a second ridge 

 or a third, the growing creek may for a time 

 fl )W northeast or southwest, but it will pres- 

 ently pass out by another water gap. Ulti- 

 mately it falls into one of the great trans- 

 verse rivers. This arrangement of parallel 

 brooks which swell the volume of a creek 

 generally flowing at right angles to their 

 courses, resembles a vine from whose cen- 

 tral system branches are trained on a trellis. 

 Although most conspicuously developed in the 

 Alleghanies, this trellis system of drainage 

 is common in regions where beds of hard 

 rock lie steeply inclined to the general sur- 

 face. The parallel branches of the system 

 are controlled by the parallel ridges between 

 each two pairs. Thus it appears that the 

 hard rocks have to this extent influenced the 

 arrangement of the streams. 



Petrolenm-Lamp Accidents. — The recent 

 report of Mr. Alfred Spencer, an officer of 

 the control department of the London County 

 Council, on petroleum lamp accidents, and 

 the measures necessary for preveuting them, 



is a very important and practical document. 

 His conclusions regarding their safe con- 

 struction and proper management are as 

 follows: (1) The oil reservoir should be of 

 strong metal, properly folded and soldered 

 at the joint, and should not be of china, 

 glass, or other fragile material. (2) There 

 should be no opening between the reservoir 

 and the burner, other than through the tube 

 which holds the wick, and this tube should 

 be extended to within a quarter of an inch of 

 the bottom of the reservoir, and should have 

 no opening into the reservoir except at its 

 base. (8) The burner should be securely 

 attached to the reservoir, preferably by 

 means of a strong and well-made screw at- 

 tachment. (4) There should be no openings 

 through which oil could flow from the reser- 

 voir should the lamp upset. (5) Every table 

 lamp should have a broad and heavy base, 

 to which the reservoir should be strongly 

 attached. (6) Wicks should be soft and not 

 tightly plaited, and should quite fill the wick- 

 tube without having to be squeezed into it. 

 (7) Wicks should be frequently renewed, and 

 before being put into lamps should be dried 

 at a fire and then immediately soaked with 

 oil. (8) The reservoir should be filled with 

 oil before the lamp is lit. (9) The lamp 

 should be kept thoroughly clean, all oil 

 should be carefully wiped ofP, and all charred 

 wick and dirt removed, before lighting. 



(10) When first lit, the wick should be par- 

 tially turned down, and then gradually raised, 



(11) The wick should not be left turned 

 down, as there is then a greater liability to 

 explosion in lamps of unsafe construction. 



(12) Lamps which have no extinguishing ap- 

 paratus should be put out as follows : The 

 wick should be turned down until there is 

 only a small, flickering flame, and a sharp 

 pirff of breath should then be sent across the 

 top of the chimney, but not dov^Ti it. (13) 

 Cans or bottles used for oil should be free 

 from water and dirt, and should be kept 

 thoroughly closed. 



The Sernm Treatment of Disease. — It is 



stated in the British Medical Journal that 

 the sorum treatment of disease probably 

 originated in the observation made by Von 

 Fodor, in 1887, that blood when drawn from 

 the body had a distinct bactericidal action. 

 " Nuttall and others then pointed out that 



