/ 



38 Hydro-oxygen Blowpipe. 



My experiments were also repeated by Mr. Rubens Peale, dur- 

 ing many successive years, at the Philadelphia Museum, for the 



amusement of visitors. 



About the year 1813-14, it was ascertained, at the laboratory 

 of Dr. Parrish, that a bladder being supplied with a mixture of 

 hydrogen and oxygen, in due proportion, and punctured by a pin, 

 while subjected to compression, on igniting the resulting jet, the 

 gas within the bladder did not explode. Of course a burning jet 

 of flame thus created, was found competent to produce, while it 

 lasted, the same effect as when otherwise generated by the same 

 gaseous mixture. 



Soon after this result was obtained, Sir Humphrey Davy dis- 

 covered, that if a lamp flame be completely surrounded by a 

 gauze of fine wire, it may be introduced into an inflammable 

 gaseous mixture without causing it to explode. This was as- 

 cribed to the refrigerating influence of the metal, keeping the 

 gaseous mixture below the temperature requisite for inflamma- 

 tion. Hence it was inferred, that if a mixture of hydrogen and 

 oxygen, while condensed within a suitable receiver, were allow- 

 ed to escape through a capillary metallic tube, so as to form a jet, 

 this might be made to burn without communicating ignition to 

 the portion remaining in the receiver. 



By means of an apparatus contrived agreeably to this idea, Dr. 

 Clark of Cambridge, England, repeated the experiments, made 

 many years before by Silliman and myself, without any other 

 reference to ours, than such as was of a nature to do injustice. 

 An exposition of the invalidity of Dr. Clark's pretensions to ori- 

 ginality was made in Silliman's Journal for 1820, vol. ii, and in 

 Tilloch's Philosophical Magazine, for 1821, vol. lvii. 



The light produced by the hydro-oxygen flame with lime 

 having been observed by Lieutenant Drummond, of the British 

 navy, was ingeniously proposed by him, as the means of illumin- 

 ation in light-houses, and in consequence, has been subsequently 

 used as a substitute for the solar rays, in an instrument known 

 as the hydro-oxygen microscope, which is a modification of that 

 which has been called the solar microscope. The name of 

 Drummond light has consequently been given to a mode of illu- 

 ation, which I originally produced as above stated. 



The instrument which was used by Professor Silliman and by 

 Rubens Peale, was that above described as having two perfora- 

 tions meeting in one. In this form it was, I believe, employed 

 by Dr. Hope, of Edinburgh, and Dr. Thompson of Glasgow, 

 who both treated it as my contrivance, anteriorly to the publica- 

 tion of Dr. Clark's memoir. 



The other form, consisting of two concentric pipes, was mod- 

 ified by a Mr. Maungham, with the view of producing a lime 

 light for the microscope above alluded to. When I saw Mr. 



