March 3, 19 10] 



NATURE 



2\ 



he car platform level, the driver can exercise control so 

 IS to cause the platform to incline to either one side or 

 he other. With the car at rest on the curve, some pack- 

 ng blocks were laid on the ground reaching to within 

 ibout a foot of the chock on one side of the car. The 

 Iriver then inclined the car so that the chock rested on 

 he packing blocks ; some planks were laid resting on the 

 jround at one end and against the car platform at the 

 >ther, so as to extend the inclined plane of the platform 

 [own to ground-level. The packing cases were then 

 lasily shoved off without the assistance of any tackle 

 vhatever. On unloading being completed, the driver 

 :aused the car to recover level immediately. Mr. Brennan 

 las not yet published a complete description of the 

 nechanism for bringing the gyroscopes back to their 

 entral position, certain patents having been applied for 

 md not yet granted. 



We then had an opportunity- of taking a run round the 

 jrcle. All passengers stood, and, despite the fact that 

 here was nothing to take hold of, perfect steadiness of 



THE FUEL QUESTION IX THE UNITED 

 STATES. 



A N important department of the United States Geo- 

 "^"^ logical Survey is that devoted to fuel. More than 

 400,000,000 tons of coal, valued at above io6,ooo,oooZ., 

 were raised in 1908, nearly the whole of which was con- 

 sumed in the countr}', and this department has made numerous 

 researches as to the best methods of utilising this coal. 

 The information acquired is published from time to time 

 in the form of bulletins, most of which are supplied free 

 or at a nominal cost. Four bulletins recently issued, Nos. 

 373> 382, 383, and 385, may be taken as indicating the 

 scope of the work done. They are entitled " The Smoke- 

 less Combustion of Coal in Boiler Plants," by D. T. 

 Randall and H. W. Weeks ; " The Effect of Oxygen iir 

 Coal," by D. White; "Notes on Explosive Mine Gases 

 and Dusts," by R. T. Chamberlin ; and " Briquetting 

 Tests at the United States Fuel-testing Plant, Norfolk, 

 Virginia, 1907-8," by C. L. Wright. The paper on 



The Brennan Mono-Rail Vehicle. 



■quilibrium was experienced by everyone. The angle of 

 leel inwards w:e estimated to be about 10 degrees on this 

 rip. An exhibition of the vehicle taking sharp curves 

 oUowed, the minimum radius being 35 feet, after which 

 ve had a trip at high speed down the straight portion of 

 he track and back again. Complete success attended all 

 he trials, and Mr. Brennan is to be heartily congratulated 

 »n the results. 



From our previous description of the track it will be 

 mderstood that its simplicity renders it very suitable for 

 nilltary purposes. The short cross-sleepers are simply 

 aid on the ground without ballast, and we noted on this 

 'isit that, at one part of the straight line, longitudinal 

 sleepers had been used. At the factory entrance a short 

 >art of the line is flush with the surface of the macadam, 

 llustrating the value of the system for tramway work, 

 't is intended to put in hand one or more trailers to be 

 :oupled to the present vehicle, in order to show the 

 iracticability of running such vehicles on trains. 



NO. 2105, VOL. 83] 



briquetting is chiefly of interest to the mine-owners and 

 coal-users of \'irginja, although the summarj- of the recent 

 literature on briquetting possesses a wider value. The 

 work described by R. T. Chamberlin in the memoir on 

 explosive mine gases and dusts had only just commenced 

 when, in December, 1907, a series of unusually disastrous 

 explosions took place in the Naomi, Monogah, and Dan- 

 mines of Pennsylvania and West Virginia. This led to a 

 diversion of the original inquirv-, the gas and dust con- 

 cerned in these explosions being subjected to a detailed 

 examination. Special attention was given to the part 

 plaved bv the methane evolved from the coal in the pro- 

 duction of these explosions, this gas being more rapidly 

 evolved the finer the state of division of the coal. After 

 this emission of methane had gone on for some tinie the 

 dust was less readily ignited, and experimental evidence 

 is given showing that the fresh dust is more dangerous 

 than old dust. 



The memoir bv Mr. D. White, on the effect of oxygen 



