It is generally taken as constant, but its value at moderate pressures is difficult to determine.
The reader will be able to make out the simultaneous motions and pressures at various points.
It was found, however, that when Oxyacetylene using acetylene under low pressures, the burner tip blowpipe.
became so heated as to cause the decomposition of some of the gas before combustion, the jet being choked up by the carbon which deposited in a very dense form; and as the use of acetylene under pressures greater than one hundred inches of water was prohibited, no advance was made in this direction.
But if hinges are introduced at crown and springings, the calculation of the stresses in the arch ring becomes simple, as the line of pressures must pass through the hinges.