170 MisceiianevHn Inteltigtm 



c. 



rativCf i. p. 98. The Peak of the Azores from the same volume, 

 p. 99, note. £din. Phil. Journal^ iii. p. 192. 



6. Earthen-iuare Reflectors. 

 To the Editor of /Ae Quarterly Journal of Science, ^c. 

 Sir — I have great pleasure in informing you, that we have 

 adopted some of the reflectors proposed by Mr. P^illington, and 

 described in your fifth volume, to the gas lamps in our city, 

 and find tliem attended with such advantages, as to induce me 

 to write to you on the present occasion. They are made of 

 earthen-ware, with the common white glaze, are about eleven 

 inches diameter, and cost about seven shillings a dozen. They 

 not only considerably increase the light, but materially contri- 

 bute to the protection of the head of the lamp, by preventing 

 its being unsoldered, or injured, by the flame ; and I am per- 

 suaded, that if known, they would be duly appreciated, and ge- 

 nerally adopted. I am, Sir, yours sincerely, 



Charles Wilkinson. 

 Bath, April 'IQ, 1820. 



7. Gas Tube. — Mr. Phipson, of Birmingham, in order to ob- 

 viate the effects produced by the action of gases on copper or 

 brass pipes, through which they pass, has adopted the plan of 

 lining them with lead. A tube is formed of rolled copper, by 

 drawing it through a plate, and the edges are soldered together, 

 so as to form a safe joint, the superfluous solder is dresfeed off, 

 and the tube again drawn ; a piece of lead pipe is then drawn 

 through a plate on a mandrill, of the diameter of the tube re- 

 quired, and placed within the copper pipe ; then by passing 

 through it a conical mandrill attached to a rod, the lead pipe is 

 forced against the inner surface of the copper tube, so as to leave 

 them in perfect contact ; or sometimes a lead pipe is prepared 

 on a mandrill, of the diameter of the tube required, and a cop- 

 per pipe, already soldered, drawn over it ; they are then passed 

 both together on a mandrill through a draw-plate, so as to 

 bring the two into complete contact. The lead pipe is proof 

 against the action of gas, and the copper pipe, at the same 

 time tliat it supports and defends it, makes a better appearance. 



