Fig. 5.
The oxycalcium lamp is represented at [Fig. 5], and it consists of a vessel with an aperture in its base, is provided with a valve to close the same when needed, and is capable of holding about a half-pint of spirits of wine. This is called the cistern, and it is placed valve downwards into a second or outer cylinder rather deeper than itself. This operation opens the valve of the cistern, and allows a sufficiency of spirit to flow out so as to fill the space between the bottom of the cistern and the bottom of the outer cylinder. From this outer cylinder proceeds a long horizontal tube, terminating in a small chamber that holds the wick, and it is here that the lamp is lighted.
Behind the wick is a steel pin for holding the cylinder of lime, and in front of the wick is the small end of a bent tube (marked o o), carrying the oxygen gas. This oxygen gas tube passes along the under side of the tube connecting the outer cylinder with the wick chamber, and extending some little distance behind the outer cylinder, there terminates in a tap. This tap is to be connected with the bag containing the oxygen gas by means of a flexible pipe.
In arranging the oxycalcium lamp for use the cistern should be filled with spirits of wine, and the wick cut off smooth. The lime cylinder is to be placed on the support, and the tap o connected with the bag containing the oxygen gas.
A weight equal to about 40 lb. or 50 lb. is to be placed on the bag, and the apparatus is ready for use. The lamp is to be lighted at the wick and the gas admitted by gradually turning the tap at the end of the tube o; the tap attached to the bag having been previously turned fully on. The oxygen gas now issues from the point of the tube in front of the flame and forces the flame against the lime, producing thus the oxycalcium light.
The quantity of gas admitted requires to be regulated to the size of the lamp flame, for if the gas be in excess, the lime will be cooled down and the light diminished. A similar loss of light will result from having too little gas; so that some attention will be required to enable the operator to adjust the apparatus satisfactorily.
The wick should be carefully put into the wick-holder in straight lengths, not twisted together, and not too tightly packed. A slight separation should be made in the top of the wick to allow the stream of gas to pass freely. The point of the jet should be about one-tenth of an inch below the top of the wick, and should not project into the wick. The wick should be kept up close to the point of the jet, and not be allowed to bend towards the lime cylinder.
The spirit to be used with the oxycalcium lamp is to be alcohol or the best methylated spirit; paraffin spirit will not do. It is best to renew the wick each time the lamp is used.
Fig. 6.