PATENTS. 



653 



light of the same candle-power. It was esti- 

 mated as the result of the Crystal Palace experi- 

 ments that an area of one half of a square mile 

 could be brilliantly illuminated at a cost of less 

 than twenty -five cents an hour. The quality of 

 the light it is claimed is greatly superior to that 

 of electricity, owing to its greater diffusive- 

 ness, rendering it less trying to the eye, and 

 therefore better for all practical purposes. 

 The carbon particles are raised to an intense 

 white heat, and the form of the flame is such 

 that they are retained in that condition for a 

 longer period than is the case with any other 

 system. The lucigen has been adopted with 

 satisfactory results at the works of the great 

 bridge over the Frith of Forth and at a large 

 number of manufacturing establishments in 

 Great Britain. 



Improved Curtain Fixture. Persons who are 

 particular about the quantity and direction of 

 the light falling through a window will be in- 

 terested in a device which uncovers at will 

 either the .whole of a window, or the upper 

 or lower half, or any part thereof. The roll- 

 er (A, Fig. 5) is provided with a longitudi- 

 nal slot through which the curtain passes as 

 shown in section at B. At the left the whole 

 appliance is shown in position for use. The 

 roller is fixed at a middle point of the sash and 

 a cord ascends over a pulley above the win- 

 dow. By pulling this upper cord the curtain 

 unwinds and the whole window is covered. 

 Continuing the hoisting operation the lower 



half is exposed. By lowering and partially 

 rolling the curtain, the central portion of the 

 window will be screened, and by lowering it to 

 the floor and then pulling the side cord, the 

 lower half of the window is covered, and by a 

 slightly different manipulation the upper half 

 is covered if the room is not high enough to 

 hoist the curtain by the upper cord. The tas- 



sels are weighted so that they balance in any 

 position, and a very complete adjustable shade 

 is thus provided for any conditions of light. 



A Gravity Lateh. The liability of springs to 

 wear out or become useless through rust or 

 mechanical complications in connection with 

 door-latches has, in the course of time, given 



rise to innumerable annoyances, and a latch- 

 lock operating by gravity has many claims to 

 consideration. The one shown in Fig. 6 is 

 very simple in construction. The diagram at 

 the left presents a front view, and that at the 

 right an edge. The casing has a central chan- 

 nel and side flanges for attachment to the door 

 at an angle of forty-five degrees. A bolt hav- 

 ing its lower end obliquely beveled rests in the 

 channel riding upon an anti- friction wheel 

 and projecting when the door is open like the 

 catch of an ordinary knob-latch. When the 

 door is closed it engages a beveled striking 

 plate, and the bolt slides upward in the chan- 

 nel, slipping at once into the mortise when the 

 door is shut, and automatically locking itself 

 in its lowest position by a shoulder near its 

 upper end. A pawl is provided at the upper 

 end, which drops into a notch, affording addi- 

 tional security. A knob on one side of the 

 door and a key on the other afford an easy 

 means of sliding the bolt upward when the 

 door is to be opened. The key acts through 

 the door upon the pawl and disengages it from 

 the other side. A set screw, however, locks 

 the bolt permanently, so that it can not be 

 opened by means of the key. 



A Self-Closing Gate. The accompanying sketch 

 shows a simple device for closing a gate by 

 means of a weight and pulleys without the usual 

 post and chain which occupy space, and are 

 generally in the way. An arm is attached to 

 the upper cross-bar of the gate, arid from its 

 end a line passes around a horizontal and over 

 a vertical pulley, the action being direct and 

 the rise and fall of the weight perpendicular and 

 close to the fence. The cut (Fig. 7) explains the 

 principle, which is so simple that any one with 

 moderate ingenuity can render himself liable 



