There are other types of generators, such as the 'Water
dropping' variety, in which the water drips on to the carbide, and the reverse, in which fine granulated carbide drops a little at a time into water; but these types are not very frequently met with and need hardly be described.
It should never be forgotten that acetylene is an explosive gas and should be treated as such. Searching for a leak with a lighted match, though perhaps permissible when the operator knows his business, may be a dangerous proceeding when the contrary is the case.
Acetylene burners are generally of the 'Batswing' type, and are as a rule four in number, mounted in a row with a reflector behind, each burner being separately controlled by its own tap (Fig. 7). An acetylene flame is very smoky, and care must be taken that the burners are not turned too high. A nipple cleaner, consisting of a fine wire in a short handle, can usually be obtained from any dealer, and is very handy.
Acetylene gas can also be used for lantern illumination in quite another way, viz. by a blast from a blowpipe, in combination with either air or oxygen, on to a special 'Pastille' provided for the purpose, or an ordinary limelight jet can be used. These methods entail the use of acetylene under pressure, and are so analogous to limelight that I shall for convenience deal with them in the chapter devoted to that illuminant.
CHAPTER V
LIMELIGHT AND THE ACETYLENE BLAST