considered in proportioning all parts of the structure which will be affected by these, loads, whether the span is to be provided with mechanical power at first or not, as it may become necessary later on to put it in. The wind load on the house must also be considered in proportioning the tower posts and all bracing between them.

CAMBER AND DEFLECTION.

The lengths of all truss members shall be such that, when the assumed uplift is applied at the ends of the span, and when the greatest live load is on the structure, the centre lines of the bottom chords from end to end of span will lie in a horizontal plane. The vertical movement of the ends, from the condition of no stress in the chords, when the weight of the finished span is supported on the falsework, to the condition of the span swung, must be very carefully figured, as upon this will depend the camber increments or decrements in lengths of members, the clearances, adjustments, etc.