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CHAPTER IX.

Quantities of Materials (Cont'd.)

IV. Special Methods of Measurement of Quantities.

2. Weights of Metals

Gauge Points and Their Use.

At the foot of Table 11 will be found the names of several of the more common metals used in construction work together with the value of what is termed the Gauge Point of that metal. In all cases this value is the ratio between the weight of any material in the metal whose gauge point it is, and the weight of the same quantity of Iron; the weight of the material being found in Iron by the use of the Table, its weight if made of any other metal is found by multiplying the weight in iron thus found by the Gauge Point of the desired metal.

For example, let us suppose the metal whose weight is desired to be brass whose Gauge Point as given is 1.09. The operation just described and with the factors given in Table 11 give the weight per linear inch of the given area if the material were iron, and to obtain its weight in brass we multiply its weight thus found in iron by 1.09 the Gauge Point given for brass— the product being the desired weight in brass.

The unit of length has been assumed in this form of measurement as one inch instead of one foot as probably covering more cases of actual problems than the foot unit, although in the cases of Beams, Girders, built up Sections, etc., the foot unit would oftenest apply.

Gauge Points of Various Metals.

Wrt. Iron— 1.00 Copper— 1.15
Cast Iron— 0.93 Brass— 1.09
Cast Steel— 1.02 Lead— 1.47
Steel Plates— 1.04 Zinc— 0.92

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