104. The oil used in lamps is of two distinct kinds. The fat greasy oils, such as seal or whale oil from animals, and olive or colza oil from vegetables. To obtain a good light from these fat oils it is necessary to make the flame hollow, and admit air into the interior, as is done in what is termed an Argand burner. In order to cause a strong current of air through the flame of an Argand, a tall glass chimney is requisite.