150 A nevj 'Modtjuation cj JSiooi/i's apparatus, &c. 



cjviired. It may also be employed in a great variety of otKe? 

 situations with ecjual convenience; as it is quite immateriiJ 

 whether the levers, A B, are suspended from above, as in thi^ 

 instance ; below, or even side-ways j and tlieir points of suspeu- 

 .sion may likewise be varied, when necessarv. by a suital)le pro- 

 vibion in their construction, so as to be placed either nearer ti> 

 the wheel and axle, in order to act upon them by the handle, G, 

 with greater leverage, to gain power ; or further from them, ta 

 gain time ; as the handle, G, then moving in a circle of lesser 

 diameter, can consequently be turned more swiftly about. 



CHI. A veiv Modifiration of Nooth's Apparatus, and of 

 Welter's Tube of Safety : — The Ckrysopmie submitted to 

 the Oxihydrogen Blotu-pipe. Comviunicated by J. Murhay, 



To Mr. Tilloch. 



Sib, — A-Iaving found the apparatus, of which the drawing 

 accompanying this is a correct portrait, a useful instrument ni' 

 my own manipulations, and considering it a valuable simplifica- 

 tion of Nooth's apparatus, as the safety-tube is an improvement 

 oi that of Welter, — Mr. JSteele of this place, the projector, hu^^ 

 been induced at my request to permit me to submit it to you - 

 which I now do, in the conviction that it will be found an im- 

 portant acquisition to the cliemist. 



I am respectfidly, sir, your most obedient servant, 

 Greenoclc, MavSl, 1817. ' J.MuRRAY. 



P. S. I have submitted the chrysnprase to the flame of the 

 oxihydrogen^blow-pipe. This gem, which is silex coloured witlv 

 oxide of nickel, has been among the most refraclory substance* 

 which I have yet exposed to its energy. Soon after it became 

 intensely red hot, it lost its colour and became Tv/ult; tinged with 

 yelloiv. The edge of the polislicd cnstal seemed abraded, aiul 

 fractures were discoverable in the cry&tal 5 but fus^ioYi was nj)t. 

 evident. J. M. 



DescriptiQn of Steelk's Modifimt'wv of Nooth's Apparatus, 

 and o/'Wki-TER's Tube if Safety. 



A is a globular receiver, to contain the liquid required to be 

 saturated with the gas arising from the retort B. 



C is a quilled balloon, the quill of which is accurately ground 

 JTito the neck of A, and nearly reaches its bottom. 



Into the neck of the balloon, C, a safety appendage, D, U 

 fitted; the bulb of which may confviin a further portion of tlie 

 liquid to be saturated (or mcjturyj if a (greater pressure be re- 

 quired). 



