Gas: its Advantages and Drawbacks - Varieties and Cleaning of Burners - Incandescent Light - Economies - Reading a Gas Meter - Chandeliers - Globes - Gas-poisoning - Acetylene Gas-Lamps: their Choice, Care, and Cleaning - Colza and Spirit Lamps - Electric Light - Candles.

GAS is the method of illuminating most in vogue; it has many advantages, and some disadvantages, amongst which may be reckoned the following:-

Advantages And Disadvantages

(1) It is available for cookery, laundry work, and warming, in addition to lighting. (2) It saves time and trouble. (3) It is safer than lamps or candles, especially where there are children. On the other hand, there are several drawbacks. (1) It is certainly the most unhealthy form of light, as it dries and heats the air; and one burner alone consumes as much oxygen as two adults. (2) The smallest escape will produce poisonous effects, and serious explosions may result from it. (3) The sulphurous vapour rapidly tarnishes silver, and injures plants, leather, and gilding.

Varieties Of Burners

There are three varieties of burners in common use. (1) The Argand (the most costly), which burns the gas from a ring of small holes, and which on an average equals thirty candles. (2) The Fishtail, or Union, which is formed by two small holes bored in the top of a closed tube, inclining towards each other, producing a flame as shown. (3) The Batwing, which is formed by a long cut through a bulb on the end of a burner. This is durable and very easily cleaned, but from the spreading of the flame it is not so suitable where globes are used as it is for kitchens and passages.

Varieties Of Burners 5Varieties Of Burners 6

In all good burners steatite or pottery tops are used. In these there is a certain contrivance which retards the gas current; the illuminating power of one of these good burners is equal to about sixteen candles, the consumption being 4 or 5 cubic feet in one hour. It is important that burners should be of a suitable size for the purposes intended; a 5-foot burner is appropriate for a sitting-room, while for a passage or bathroom a 2-foot burner would be sufficient.

Governors

In many institutions economy in gas is secured by the use of a gas-governor, which acts as an automatic gas-tap, when fixed between the meter and the gas lights; closing and opening with every increase and decrease of pressure from the street mains. The cost varies from 1 15s. to 17, according to the size of the pipes to be controlled.

To Clean Burners

For this purpose an old toothbrush, or a corner of an old post-card should be used, not a wire, as this enlarges the holes and leads to the use of more gas. Grease may be removed by rubbing with paraffin, stale beer, or vinegar.

INCANDESCENT BURNERS are composed of 99 per cent. thoria and 1 per cent. ceria. The brightness is due to alternate oxidation and reduction of two parts carbon and three parts oxygen. The mantle fabric consists of "de-nitrated" collodion, which is steeped in mixed cerium and thorium nitrates in correct proportions. The mantle fabric is then woven into the familiar form, and on burning off the nitrates and collodion the ordinary mantle is left. After fixing a new one the taper should be applied to the narrow top of the mantle, the flame then travels evenly round till it reaches the base. The length of life of a mantle depends on the manner in which it is woven and the care it meets with; it usually lasts from 1000 to 3000 hours, and then gradually loses its lighting powers. This loss is due to the presence of dust, which clogs the pores of the mantle and causes bits of silica to fuse on the fabric. There is less danger of injuring a mantle where a by-pass is used : this costs 1/6 extra, or with lever and chains 2/6.

The most efficient form of incandescent light is that given by the "Block" burner, one alone being equal to three hundred candles, and costing (according to the booklet issued by the Gas Company) one farthing per hour, using eight parts of air to one of gas. The mantle, which costs 1/3, is made of more durable materials than the ordinary varieties, and is mounted on a brass cap with a double nickel wire support, which ensures its comparative longevity. The price of the burner is 5/6.

The inverted incandescent burners, which shed the light downward, and thus do not affect the ceilings, cost 6/6 each; the small inverted "Bijou" burners 4/6 each. These may be fixed to an ordinary bracket, either singly or in clusters.

The "self-lighting" arrangement costs 9d. for each light to which it is attached. The pneumatic gas-lighting apparatus, costing 6/6 for each burner, is a great convenience, since by its means the gas may be switched on from the doorway in exactly the same way as the electric light.

Economy may also be ensured by turning off the gas from the meter at a given hour each night and also by day if no stoves are used. This prevents leakage through small escapes; but it is most important to see that all taps are turned off first, or when the gas is again turned on and lights applied explosions may result, if not lighted at once.

The price of gas varies much in different localities, and at different times. The usual price in Cardiff is 2/10 per 1,000; in 1901 it went up to 3/4, owing to the raised price of coal; in 1902 it fell to 3/1; in 1913 it is now'2/6 per 1,000 cubic feet. At Hull, in 1901, it was 1/10; 1902, 2/- per 1,000 feet.