FoRcixG-HousE Miscellanies. 375 



2. With set-o£E. Jan. 31-Feb. 10 



Average temperature at boiler 193° 



Average temperature at far end 123° 



C. Steam Circulation^ 1 lb. or more pressure. — 



1. Straight run. Jan. 16-31 



Average temperature at boiler 21 1 



Average temperature at far end 212° 



2. With set-off. Jan. 31-Feb. 10 



Average temperature at boiler 211° 



Average temperature at far end 212° 



o 



It is thus shown {A) that whilst the readings at the two ends of 

 the run, with water, were very nearly the same in the straight pipe, 

 they were widely different when the crook or set-off was inserted. 

 I^ot only was the temperature at the farther end less with the 

 crooked run than with the straight one, but the temperature at the 

 boiler was much higher, showing that the impediment had increased 

 the pressure and consequently the temperature in the fore part of 

 the run. This explains why it is that water pipes are often so hot 

 near the boiler but so cold at the further end of the house : some 

 impediment, like crooks, dips, elbows or partially filled pipes, is 

 probably in the circuit. With steam under low pressure, however 

 (C), there was no difference in the temperatures at the two ends 

 between the straight and crooked runs. 



Another point receiving attention in the second experiment was 

 the time required to heat up steam and water systems. It is said by 

 many persons that inasmuch as water begins to move before steam 

 forms, therefore hot water will warm up a house sooner than steam. 

 It is true that water moves off first but it travels slower ; it is soon 

 overtaken by the steam. Our tests showed that 



7. In starting a new fire with cold water, circulation begins with 

 hot water sooner than with steam, but it requires a much longer 

 time for the water to reach a point where the temperature of the 

 house is materially affected than for the steam to do so. 



We also found that 



8 The length of pipe to be traversed is a much more important 

 consideration with water than with steam, for the friction of the 

 water upon the pipe is much greater than the friction of steam, and 

 a long run warms slowly with water. 



