174 APPENDIX V The volume of gas per second is found as follows : 0iooo = 3.3 :5 = 0m366 01000 14 The consumption of coal per second is arrived at as follows: 1 kg of coal gives about 9 m3 00 of gas, and; accordingly: £ = ; 0.14 = 0 kg 0155 per second=about 55 kg 80 per hour. 9.00 The dimensions of the fireboxes were the same as before, o,=4XlX0.56 = 2m224, and corresponded with a fuel consumption of 25 kg of coal per square meter of grate per hour. The rate of combustion was rather slow, a condition which is particularly favorable for realizing theoretical combustion. The area of the hot gas ports from the firebox: Ği = 4XO. 16X0.32 = 0 m2 20. The velocity in these parts is low: ^iooo = 0.66 : 0.20 = 3 m 20 per second. The area of the waste gas ports is co2 = 16XO.24X0.12 = 0 m2 46. The velocity in these ports is ^iooo = 0.66 : 0.46 = 1 m 43 per second. These low velocities make it certain that the waste-gas flue will receive the coolest gases in the chamber and are also very favorable to the obtaining of a uniform temperature over the whole hearth of the muffle. The height of the waste-gas flue according to Yesmaim's formula is 0 m 38. The computation for the chimney was not made, as the existing chimney was amply sufficient and gave a large margin of safety, the velocity of the gases at its outlet being very nearly zero.