234 The Safety-lamp. 
gold medal, or one hundred and_ fifty florins, at the option of 
the author. 
An anonymous individual has offered to the French Royal 
Academy ‘of Sciences a sum of 7000 francs for the foundation of 
a prize of experimental prnsonny: 
nm ee 
XXXVII. Intelligence and Miscellaneous Articles. 
THE SAFETY-LAMP. 
Ox this subject we haye received a letter fr om an anonymous 
correspondent, from which we take the following par agraph: 
* Ina letter to Dr. Thomson which appeared in the Annals 
of Philosophy for April 1516, p. 319, the following statements 
eccur respecting the lamp for mines : 
** You have not developed the prineiple upon which. the be- 
nefits of the gauze depend. You talk of a fixedness of the air 
which.cannot be. If an explosion takes place without any con- 
siderable extrication of heat, the contact of the adjacent wires 
cools down the red-hot air, and renders it incapable of kindling 
combustion without,’”’. It is clear, therefore, that Dr. Thomson 
did not before that time possess the principle upon.which the 
non-communication of combustion through wire-gauze or multi- 
plied holes in metal depends; and it is also clear that the prior 
discovery and development of the wire-gauze principle by which 
the inflammation of gases is arrested, belongs to the writer of that 
letter, if at that time no statement of the principle had appeared. 
tn print. If it had, Dr. Thomson. weuld have known of it. If 
it had, let the time be stated. Af it had not, let due credit be 
given to the writer of that letter.” 
The remaining part of our correspondents letter, we. withhold 
as irrelevant.to the question on which he treats.. He has.“ still 
some remaining doubts of the perfect safety of the lamp,” and 
to have these “removed he proposes that ‘the lamp, should be 
plunged into various mixtures of hydrogen and oxygen gases— 
of artificial carburetted hydrogen gas with oxygen. No such 
_ Mixtures ever exist in mines, and they have therefore nothing to 
do with the lamp, as a safe-lamp, for mines. Our correspondent 
next proposes that similar experiments shoul:t be made with in= 
flammable “ yas from the mine by plunging the lamp entirely i into 
various mixtures of it with common air in. vessels i in the Jabora- 
tory, not applying it, to blowers in the mines.”? Such experi- 
ments as he recommends with the gas of. the mine, have been 
often. made-already, and always. with results favourable to. the 
safety of the lamp, - arian 
