262 Progress in Science. (April, 
Under the name of the Aérophore, M. Denayrouze has brought out an 
ingenious apparatus for furnishing to the miner a supply of fresh air in the 
midst of a deleterious atmosphere. The air is compressed by a double- 
barrelled pump of peculiar construction, the cylinders being movable, whilst 
the pistons are fixed, thus reversing the usual arrangement. By means of a 
regulator the pressure of the air may be adjusted at pleasure. The miner 
inhales the air through an india-rubber mouth-piece, whilst a supply is 
delivered on similar principles to hislamp. The Denayrouze lamp is specially 
construéed to burn independently of the surrounding atmosphere, and derives 
its air solely from the lamp-regulator. In one form of the Denayrouze appa- 
ratus the air is compressed into strong reservoirs, at a pressure of 20 atmo- 
spheres. Experiments putting the apparatus to tests which seem to be 
sufficiently severe have recently been conducted in this country,—it is said 
with much success. No doubt such an apparatus might be of special service 
in re-opening a pit after an explosion, and before it is expedient to admit 
fresh air; but it is evident that apparatus of this kind can have but a limited 
application, and is not likely to be used for prolonged work. 
To prevent the collier from tampering with his Davy-lamp, Messrs. Bailey 
and Waddington have patented the application of a seal to the locked lamp. 
This seal is enclosed in a case, and so arranged that the miner cannot un- 
screw his lamp and expose the light without breaking the seal, and thus 
convicting himself. 
At a recent meeting of the North Staffordshire Institute of Mining and 
Mechanical Engineers, a paper was read, by Mr. T. M. Goddard, on “ Better 
Communication in Pit-Signalling by means of Electricity.” He described the 
system of eleGrical signalling employed with much success at the Golden- 
hill Colliery. This system was said to be much more economical than the 
ordinary method of using a stranded bell-wire, and not so liable to get out of 
repair. Moreover, less room is required in the shaft with this system. 
The subje@ of coal-cutting by machinery was recently brought before the 
Cleveland Institution of Engineers, by Mr. J. S. Jeans, of Darlington. After 
tracing the history of such machinery, he described two of the most popular 
coal-cutters,—namely, Mr. W. Firth’s machine, and the Gartsherrie coal- 
cutter of Messrs. Baird. The latter has been successfully working at the 
Hetton Colliery. 
‘An Essay on the Prevention of Colliery Explosions,” by Mr. Emerson 
Bainbridge, of Sheffield, has appeared in the columns of the *“ Colliery 
Guardian.” After enquiring into the cause of such accidents, the author 
examines how far the means now used for their prevention can be considered 
successful, and points out what he considers should be done by legislation 
and by mining-engineers to prevent such explosions, and to lessen their fatal 
effects when they do occur. Mr. Bainbridge’s experience and position should 
secure a respectful attention to his views. This essay is one of those written 
in competition for the Hermon prizes. The three prize-essays—those of 
Mr. W. Galloway, Mr. W. Creswick, and Mr. W. Hopton—have been pub- 
lished in a separate volume. Another of the competitive essays, by Mr. J. 
Harrison, of Eastwood, Notts, has appeared in the *“t Mining Journal.” 
An “ Official Report on the Coal-Fields of Victoria,” prepared by Mr. J. 
Mackenzie, the Government Examiner of Coal-fields in New South Wales, 
has been recently issued. It contains a careful description of the several 
coal-deposits of the Colony, illustrated by sections, and offers suggestions 
where search should and should not be made for payable seams of coal. 
Mr. H. B. Medlicott has published, in the ‘‘ Memoirs of the Geological 
Survey of India,’ some ‘‘ Notes on the Narbada or SatparA Coal-Basin.” It 
seems probable that we have in this basin a more complete representation of — 
the great plant-bearing rock-series of India than in any other part of the 
Peninsula. The writer advises that the experiment of boring for coal within 
the field, at a distance from the actual outcrop, should be made at Budi, in 
the Dudhi Valley. 
