Tim spark arrestcr, although one of tlle earliest of the numerous improvements which have contributed to the advancement of American locomotive engineering, has, as yet, tailed to attain a degree of perfection Commensurate with that of many constructive details of later origin. While from its earliest period to the present it has |'eceived continued attention, and has probably been the subject of more experiment and inventive eflbrt than any other adjunct of the locomotive, the variations in the present practice, which will be obvi-,~us to even an unskilled observer, show clearly that the standard has not yet been arrived at. The boilers, frames, cylinder attachment :rod valve gearing of different builders have been reduced to unitbrmity in all substantial particulars, but there is a considerable range of difference in the construction of spark arresters.
As preliminary to a review of the history and present development of locomotive spark arresters it may be remarked, that to constitute a pe~:fect one, there would be required a device which would offer no impediment to the draught, and at the .same time completely bar the