Caro has stated that to derive the best results a mantle needs to
contain a larger proportion of ceria than the 1 per cent. present in
mantles made according to the Welsbach formula, that it should be
somewhat coarser in mesh, and have a large orifice at the head. Other
authorities hold that mantles for acetylene, should contain other rare
earths besides the thoria and ceria of which the coal-gas mantles almost
wholly consist. It seems probable, however, that the composition of the
ordinary impregnating fluid need not be varied for acetylene mantles
provided it is of the proper strength and the mantles are raised to a
higher temperature in manufacture than coal-gas mantles by the use of
either coal-gas at very high pressure or an acetylene flame. The
thickness of the substance of the mantle cannot be greatly increased with
a view to attaining greater stability without causing a reduction in the
light afforded. But the shape should be such that the mantle conforms as
closely as possible to the acetylene Bunsen flame, which differs slightly
with different patterns of incandescent burner heads. According to L.
Cadenel, the acetylene mantle should be cylindrical for the lower two-
thirds of its length, and slightly conical above, with an opening of
moderate size at the top.
Pages:
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547