The main difficulty which the condenser ought to overcome and upon which its efficiency should depend is the removal of naphthalene; this compound, which is present in the gas, condenses on cooling to a solid which crystallizes out in the form of white flakes, and the trouble caused by pipe stoppages in the works as well as in the district supplied is very considerable.
For local services where stoppages are frequent the demand is for engines capable of quickly ' At the beginning of 1908 the Great Western's loading gauge on its main lines was widened to 9 ft.
It has been found in practice advantageous to prepare the canes for crushing in the mills, as above described, by passing them through a pair of preparing rolls which are grooved or indented in such manner as to draw in and flatten down the canes, no matter in which way they are thrown or heaped upon the canecarrier, and thus prepare them for feeding the first mill of the series; thus the work of crushing is carried on uninterruptedly and without constant stoppages from the mills choking, as is often the case when the feed is heavy and the canes are not prepared.