Arizona republican., 1916-04-02

utensils and vessels employed by brew cries, preserve Q manufacturers and similar industries where heat conduc-
 tion, non- -corrosion and non poison GUS nature are essential.
 The use of aluminium wire as con-
 ductor in long distance power trans
 mission schemes has been carried on in
 a limited way and there is the prom
 ise of some expansion in this depart ment of consumption. A recently de- veloped branch Of the aluminium in- dustry is the manufacture of the metal in the form of powder for use as a paint pigment. in explosives in litho graphing and in printing. There has been some increase in the use of alum mum foil, displacjng tin foil for wrap i ping such articles as tobacco and candy.
 ! On the whole, while aluminium pro- 1 auction is progressing it's progress has been so slow and of such negative na-
 ture as to promise no interference with 1 the copper industry. The demand for i aluminium at present prices has not de- veloped to such an extent as to unset 1 tie conditions as between aluminium
 and copper.
 1 As is generally known. copper is a better electrical conductor than alum l mum; and mechanically, it is much stronger; for equal cross section alum
 inum has about half the strength of lcopper; and for the same electrical con- lductivity the breaking point of alum | ok 1f copper wire. This means that on a power transmission line, the aluminium 1 wire is about 80 per cent that of cop
 per wire required to break the copper wire. assuming that neither wire was
 scratched or nicked. Aluminium. being
 quite soft, is more liable 10 slight me-
 cfanical injuries from erecting oi
 handling. Sudden breaking of alumi- mum wires occurs from time to time iay reason uf injuries suffered durine erection. Ar arc due to short cir
 cult or to wires mOmentarily swinging
 together, may cause serious damag,
 to an aluminium line on account of tn, } low fusing point of aluminium, thu !, burning and biting the wire. and re ducing the mechanical strength. Witt , copper, however, the arc has little 0 s no effect. Aluminium is cheaper thai , copper when the two are compare merely on the basis of .conductivit and will furnish more conductivity fo s q dollar than copper. For the same con ductivity, aluminium is considerabl s lighter than copper, the ration bein to l. This might indicate that lighte s towers could be used. Experienc s shows that the reverse is the case. be 1 cause it is not the dead-weight of tn
 strength of the tower, but the strain
 i caused by winds. Aluminium has
 cross- section 64 per cent larger tha
 the equivalent copper wire, therefor e offers more resistance to the win
 and causes a greater side pull. Undt
 sleet conditions a greater area of slee Il will collect on aluminium than on cor c per, and at such times there are ger e orally strong winds. Aluminium, on at = count of it's greater cOefficient of ey n pansiCn and low tensile strength rt d quires higher towers, or towers place l. closer together. Aluminium is not sui IT able when there is abrasive action 0 = wire, SucT as sTOlley wire. nor IS o suitable for smaller sizes of wire sue r. as telephone wire. which is invariab e of copper Copper is better suited f, e. cables and insulated wires on accOul n of it's smaller diameter and equal C; Id paeit..
 r. Those who are predicting the boy 10 vows for cOppers will need to turn
 some oher kind of alarm. Copper h. 10 not yet hoisted any signals of distre d, over the advent of aluminium into u Ia metal situation and the prospect is no th so remote, considered in connecti. m with the depletion of copper deposit yc as to have been dismissed long ago
 close students of the two products. in The recent readjustment of prices ne the metal market has caused aluminu to-l to advance even more than copp, 1T. which is an additional barrier again a it superceding copper as a substitu