Particular attention was paid to the nature of the exhaust ventilation at the “heading” posts, as this is the most important point in the protection of the workers. It was provided in eight out of the nine principal yarn-dyeing factories. The exception was one where the work was said to be solely for the home market. In one a 2 foot 6 inch Blackman fan was placed in the wall without connection of the “heading” posts with it by means of ducts and hoods. In four, hoods and ducts of wood, square in section, with right-angle bends, had been locally applied to the posts. In other four, hoods and ducts were of metal, circular in section. The velocities in feet per minute (obtained with a Davis self-timing anemometer) were taken at the opening into the branch duct behind or under the post. The value of anemometric tests in detecting blockages or interference in the ducts is evident from the table on p. 300. +----+-----+---------+-----+--------------+----+---------+----+ | | | | | | | | | | (1)| (2) | (3) | (5) | (6) | (7)| (8) |(10)| | | | | | | | | | +----+-----+---------+-----+--------------+----+---------+----+ |Fan.|Fan. |Fan. Fan.| Fan.|Fan. Fan. Fan.|Fan.|Fan. Fan.|Fan.| | 240| 820 | 330 Nil|1,200| 420 450 210| 780| 570 700| 850| | 450| | 450 20| | 420 510 210| | 570 700| | | | | | | | | | | | 480| 270 | 450 270| 780| 360 420 390| 660| 540 490| 850| | 480|(750)| 420 270| | 360 420 430| 540| 570 570| | | | | | | | | | | | 480| 330 | Nil 250| | 270 120 420| 510| 540 530| | | 450|(440)| Nil 300| | 300 120 490| | 540 540| | | | | | | | | | | | 324| 320 | 300 180| | 350 480 450| 300| 300 450| | | 280|(420)| 250 150| | 290 480 420| | 300 450| | | | | | | | | | | | 25| | 130 350| | 430 390 510| | 420| | | 25| | 220 180| | 420 360 460| | 400| | | | | | | | | | | | | | 360 300| | 240 420| | | | | | | 240 280| | 450 480| | | | | | | | | | | | | | | | Nil 210| | 390 | | | | | | | Nil 210| | 390 | | | | | | | | | | | | | | | | Nil| | | | | | | | | Nil| | | | | | +----+-----+---------+-----+--------------+----+---------+----+