G8 ANNUAL OF SCIENTIFIC DISCOVERY. 



sure of gas, the fibres being disposed transversely to the passage of the gas, 

 and held together by perforated or other porous plates. By means of suita- 

 ble connections between these porous plates, he causes the fibres to be com- 

 pressed more or less, according to the density of the body required, which 

 will also be according to the initial pressure of the gas. The fibrous mate- 

 rial being held somewhat loosely together, the pressure of the gas produces 

 this effect. The greater the initial pressure becomes, the more the fibres are 

 compressed together, rendering it more difficult for the gas to permeate. 

 Thus, by the self-action of the gas on the regulator, the exit pressure is regu- 

 lated and rendered uniform. In order to intercept the grosser impurities of 

 the gas before passing through the regulator, a little loose wool is placed be- 

 tween the ingress passage and the body of fibrous material before mentioned, 

 which latter also has a similar effect in filtering and purifying the gas. 

 Mechanics' Magazine, No. 1830. 



BACHELDER'S COAL-OIL LAMP. 



This lamp is designed for burning all kinds of coal oils without employing 

 the common glass chimney, and thus avoiding the expense of their breaking 

 and the inconvenience of the lamp getting out of order from that cause, and 

 also to obtain the greatest amount of illumination from the combustion of a 

 given amount of oil. The invention consists in the use of tapers or wick- 

 tubcs, placed below and on both sides of a flat wick-tube or main illuminat- 

 ing burner, in combination with a suitable cap, thus supplying sufficient 

 oxygen completely to bum the oil without a chimney, and also without rais- 

 ing the cap so as to obscure a large portion of the flame. The lower part of 

 the cap is screwed upon the lamp in the usual manner. Above this is a retic- 

 ulated ring, for the purpose of admitting air under the wick-cap, which is 

 slotted at the top to fit a flat wick. This ring is removable for the purpose 

 of cleaning. By the contraction of the cap near the top, the air is concen- 

 trated upon the flame. Into the lower part of the cap are inserted the usual 

 wick-tube, and likewise two very small and short wick-tubes. By this ar- 

 rangement, the lamp, when trimmed and lighted, has a stronger draft on 

 account of the tapers in the short tubes; consequently the outer cap may be 

 lowered upon the main w r ick-tube, so that the illuminating flame is almost 

 entirely above the cap. In other lamps, where the draft is to be produced 

 by the wick-cap alone, it is necessary to elevate this cap, so as to give a con- 

 siderable volume of heated air in the upper part of the cap, in order to cre- 

 ate sufficient draft ; but this elevation of the cap obscures more of the flame, 

 and lessens the illuminating power of the lamp. On the contrary, by the 

 use of the small draft-lights, the top of the cap may be adjusted about half 

 an inch lower upon the illuminating burner without causing the lamp to 

 smoke; consequently it is practicable to secure a greater illuminating power 

 from a given amount of oil, and to dispense altogether with glass chimneys, 

 which are liable to break, difficult to keep clean, and otherwise objectiona- 

 ble. Journal Franklin Institute, Oct. 1859. 



NEW VENTILATOR. 



A correspondent of the New York Tribune proposes a plan for ventilating 

 rooms warmed by stoves, which is as follows : Apply a vertical pipe ,to the 

 front of the chimney, into which the lower end should enter below the 



