+----------------------------+-------+--------+--------+-----------+---------+---------+----------------+----------+---------+------+
| | | | | | Air | |Water Evaporated| Water | | |
| | | | | Coal |Pressure |Chimney |per lb. of Coal.| Evapor- | Thermal |Effic-|
| | Grate |Heating |Duration| burned |in Stoke-|Draught--+-------+--------+ated per |Units per|iency |
| Description of Boiler. | Area |Surface |of Trial|Per sq. ft.| hold-- |Inches of| |From and|sq. ft. of| lb. of | of |
| |sq. ft.|sq. ft. | Hours. | of Grate |Inches of| Water |Actual | at 212 | Heating | coal. |Boiler|
| | | | | per Hour. | Water. | | | deg. F.| Surface. | | %. |
+----------------------------+-------+--------+--------+-----------+---------+---------+-------+--------+----------+---------+------+
|Ordinary cylindrical single-| 81 | 2308 | 25 | 14.2 | Nil | 0.36 | 8.56 | 10.26 | 4.26 | 14,267 | 69.7 |
| ended; 3 furnaces; 155 lb. | " | " | 24 | 13.9 | " | 0.50 | 8.84 | 10.33 | 4.32 | 14,697 | 68.0 |
| working pressure; closed | " | " | 9 | 30.3 | 0.81 | 0.39 | 7.93 | 9.27 | 8.46 | 14,686 | 61.4 |
| stokehold system.[1] | " | " | 8-1/2| 29.1 | 0.65 | 0.32 | 8.84 | 10.34 | 9.05 | 14,612 | 68.4 |
+----------------------------+-------+--------+--------+-----------+---------+---------+-------+--------+----------+---------+------+
|Ordinary cylindrical single-| |2876 in | | | | | | | | | |
| ended; 3 furnaces; 210 lb. | |boiler, | | | In Ash- | | | | | | |
| working pressure; closed | 63.2 |766 in | 13 | 20.6 | pit | 0.58 | 11.30 | 12.33 | 5.14 | 14,475 | 82.3 |
| ashpit, Howden system.[2] | | air | | | 1.53 | | | | | | |
| | |heaters | | | | | | | | | |
+----------------------------+-------+--------+--------+-----------+---------+---------+-------+--------+----------+---------+------+
|Niclausse water-tube; 160 | 46 | 1322 | 8 | 12.8 | Nil | 0.20 | 8.41 | 10.15 | 3.75 | 14,680 | 66.9 |
| lb. working pressure. | " | " | 8 | 21.9 | " | 0.20 | 8.01 | 9.40 | 6.11 | 14,760 | 62.1 |
| | " | " | 37 | 20.2 | " | 0.29 | 7.62 | 9.00 | 5.44 | 14,600 | 60.5 |
+----------------------------+-------+--------+--------+-----------+---------+---------+-------+--------+----------+---------+------+
|Niclausse water-tube; | 34 | 990 | 9 | 14.0 | 0.10 | 0.23 | 8.77 | 10.50 | 4.17 | 14,640 | 69.8 |
| 250 lb. working pressure. | " | " | 9 | 22.0 | 0.27 | 0.23 | 7.68 | 9.06 | 5.74 | 14,640 | 60.4 |
| | " | " | 90 | 15.4 | Nil |Not asce-| 7.61 | 9.08 | 4.00 | 14,630 | 59.9 |
| | | | | | | rtained | | | | | |
+----------------------------+-------+--------+--------+-----------+---------+---------+-------+--------+----------+---------+------+
|Babcock water-tube; 3-3/16 | 36 | 1010 | 9 | 13.0 | " | 0.26 | 9.31 | 11.02 | 4.30 | 14,590 | 73.2 |
| in. tubes; 260 lb. working | " | " | 9 | 20.0 | 0.18 | 0.20 | 8.58 | 10.11 | 6.13 | 14,590 | 67.0 |
| pressure. | " | " | 90 | 14.5 | Nil |Not asce-| 8.09 | 9.53 | 4.18 | . . | 63.1 |
| | | | | | | rtained | | | | | |
+----------------------------+-------+--------+--------+-----------+---------+---------+-------+--------+----------+---------+------+
|Babcock water-tube; 1-13/16 | 62 | 2167 | 28 | 18.4 | " | 0.45 | 8.94 | 10.61 | 4.61 | 14,520 | 70.7 |
| in. tubes; 270 lb. working | " | " | 24 | 19.2 | " | 0.47 | 8.93 | 10.59 | 4.82 | 14,390 | 71.1 |
| pressure.[3] | " | " | 12 | 20.5 | " | 0.42 | 9.42 | 11.04 | 5.41 | 14,080 | 75.8 |
| | " | " | 7 | 28.9 | 0.50 |Not asce-| 8.54 | 9.88 | 6.91 | 14,390 | 66.3 |
| | | | | | | rtained | | | | | |
| | " | " | 30 | 19.9 | Nil | 0.38 | 10.11 | 12.00 | 6.01 | 14,530 | 79.9 |
| | " | " | 29 | 27.1 | 0.66 | 0.23 | 9.96 | 11.67 | 8.05 | 14,630 | 77.1 |
+----------------------------+-------+--------+--------+-----------+---------+---------+-------+--------+----------+---------+------+
|Belleville water-tube with | 44 | 910 in | 24-1/2| 15.8 | Nil | 0.36 | 9.65 | 11.46 | 4.94 | 14,697 | 77.2 |
| economizers; 320 lb. | " | boiler;| 24 | 17.4 | " | 0.39 | 9.33 | 11.00 | 5.30 | 14,805 | 71.8 |
| working pressure. | " | 447 in | 11 | 19.8 | " | 0.43 | 9.39 | 11.03 | 6.38 | 14,578 | 73.3 |
| | " |economi-| 8 | 27.2 | " | 0.39 | 8.28 | 9.79 | 7.78 | 14,611 | 65.0 |
| | |zer;1357| | | | | | | | | |
| | | total. | | | | | | | | | |
+----------------------------+-------+--------+--------+-----------+---------+---------+-------+--------+----------+---------+------+
|Yarrow water tube; 1-3/4 in.| 56 | 2896 | 26 | 16.9 | Nil | 0.31 | 9.57 | 11.45 | 3.12 | 14,750 | 75.0 |
| tubes; 250 lb. working | " | " | 26 | 18.2 | " | 0.31 | 9.37 | 11.33 | 3.30 | 14,500 | 75.7 |
| pressure. | " | " | 25 | 21.3 | " | 0.31 | 8.83 | 10.45 | 3.63 | 13,500 | 75.2 |
| | " | " | 30 | 35.4 | 0.53 | 0.26 | 8.82 | 10.59 | 6.04 | 14,430 | 70.9 |
| | " | " | 8 | 41.9 | 0.86 | 0.31 | 8.24 | 9.94 | 6.69 | 14,500 | 66.3 |
| | " | " | 8 | 33.7 | 0.31 | 0.30 | 8.39 | 9.93 | 5.47 | 14,680 | 65.4 |
| | " | " | 8 | 39.8 | 0.82 | 0.24 | 8.85 | 10.43 | 6.81 | 14,530 | 69.5 |
+----------------------------+-------+--------+--------+-----------+---------+---------+-------+--------+----------+---------+------+
|Durr water-tube; 250 lb. | 71 |2671 in | 26 | 16.1 | Nil | 0.39 | 7.95 | 9.50 | 3.24 | 14,500 | 63.8 |
| working pressure. | " | boiler;| 26 | 17.7 | " | 0.30 | 7.06 | 9.28 | 3.43 | 14,620 | 61.7 |
| | " | 140 in | 25 | 21.1 | " | 0.31 | 7.62 | 9.08 | 4.05 | 14,650 | 60.3 |
| | " | super- | 7 | 33.8 | 0.70 | 0.36 | 7.72 | 9.29 | 6.59 | 14,570 | 62.7 |
| | " | heater;| 8 | 26.7 | 0.33 | 0.35 | 7.86 | 9.26 | 5.30 | 14,320 | 63.1 |
| | " | 2811 | 8 | 34.6 | 1.11 | 0.20 | 8.02 | 9.53 | 7.02 | 14,230 | 64.8 |
| | " | total. | 22 | 34.8 | 0.73 | 0.16 | 6.84 | 8.06 | 6.02 | 14,430 | 54.0 |
| | " | | 24 | 29.9 | 0.35 | 0.12 | 7.62 | 9.00 | 5.75 | 14,240 | 61.2 |
| | " | | 20 | 19.9 | Nil | 0.21 | 7.30 | 8.33 | 3.66 | 14,240 | 58.6 |
+----------------------------+-------+--------+--------+-----------+---------+---------+-------+--------+----------+---------+------+
[1] In the first three trials no retarders were used in the tubes. In
the last trial retarders were used.
[2] In this trial retarders were used in the tubes.
[3] The first four trials were made with horizontal baffles above the
tubes; the last two trials with the baffling described in the text.