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The Optical Magic Lantern Journal and Photographic Enlarger.
79
to the orifice of the gas tap, expecting that if all the air had been expelled the gas would light, and if not, that it would fizzle. However, the moment I applied the light a tremendous explosion followed, as loud as the discharge of a heavy piece of ordnance, and the generator was blown into fragments. My own escape was miraculous, for I was standing with my face close to the top of the generator, but I received only a cut on the lip, the force of the explosion being away from where I was standing. As
the end of the gas outlet is at least two feet | from where the gas enters the tube inside the . generator, I do not see how applying a light at |
the orifice could fire the gas inside the generator, unless acetylene gas has more dangerous characteristics than any other lighting gas. Perhaps some of the readers of this journal can throw some light upon the accident ? ”
After reading this, we feel that we must again emphasise one or two points that we have several times tried to impress upon users of generators. One is that when once the calcium carbide has become wet it will, in spite of having been withdrawn from the water, continue to slowly give off a quantity of gas, and if this be not used up, and the bell container be small, it will become filled with gas and the overflow will bubble up through the water. The remedy for this is a larger container. Another point is to keep a light away from the generator.
The cause of the explosion
is not far to seek; given an explosive mixture of gas coming from a pipe of large diameter with little or no pressure of gas behind it, we have the very best conditions fora blow-up if a light is applied. If under these conditions, pressure had been applied on the gasometer, it is possible that the flame would have remained and burned at the outlet. It must be remembered that in the generator spoken of, it is only the weight of the bell tank which gives pressure to the gas, which pressure is ample when the gas is used
at the extremely small orifice of the burner with |
which it is intended to be employed. Even under the conditions spoken of by Mr. Miller, had he reduced the outlet pipe (say, by inserting a burner in it) the pressure would then have been ample to prevent firing back, and until the pro
portion of air in the gasometer had been reduced, |
the holding of a lighted match at the burner would merely have blown the flame out. At the next stage, or when the proportion of air became diminished, the mixture would burn
: the London County Council.
with a faint bluish light, which would gradually become brighter as the air became expelled, when the acetylene would give its utmost brilliancy.
We must congratulate Mr. Miller on his
| miraculous escape, and hope that the above
few hints will assist him and other readers to a better understanding of the working of a gas generator. At the same time, we consider that the instructions sent out with acetylene generators are far from sufficient to put a beginner on his guard as to what might happen under certain circumstances.
During some experiments several months ago, we showed that by allowing air to bubble up through the water used in a generator, which water was impregnated with acetylene gas, even this when collected ina jar would burn.
Aft
Carbide of Calcium.
: LONDON COUNTY COUNCIL.—PUBLIC CONTROL
DEPARTMENT.
ABSTRACT OF THR REGULATIONS AS TO THE KEEPING, SALE, AND CONVEYANCE OF CARBIDE OF CaLciuM IN THE MbsTROPOLIS.
This Abstract has no legal validity, and is intended only for the information and guidance of the persons concerned. For further information reference should be
' made to the Petroleum Acts, and to the Order in Council
dated 26th February, 1897.
GENERAL,
1. By an order in Council, dated 26th February, 1897, Carbide of Calcium can only be kept in pursuance of a license granted by the local authority.
2. No exemptions from this provision are made, so that a license is necessary for the keeping of any quantity of the Carbide, whether for sale or private use.
3. Where Carbido of Calcium is—
(a) Kept at any place; or
(b) Sold or exposed for sale, the vessel containing it shall bear a label stating in conspicuous characters, the words, “Carbide of Calcium,” ‘‘ Dangerous if not kept dry,” and with the following caution :— “The contents of this package are liable if brought into contact with moisture to give off a highly inflammable gas,”’ and also the name and address of the owner or vendor.
LICENSES.
4. Application to the Council fer a license to keep Carbide of Calcium at any place in the County of London (except the City of London) must be made upon the form provided for the purpose, which can be obtained by application in writing, addressed to the Chief Officer, Public Control Department of the London County Council, 21, Whitehall-place, S.W. .
5. Every application must be accompanied by a fee of 5s. in money, or, if sent through the post, by cheque or postal order for that amount payable to the order of The fee will be returned to the applicant if the license be not granted.