54 The N.Z. Journal of Science and Technology. [Jan. 
All such sources partake of the character of by-products, and as such 
are variable in quality and fluctuating in quantity as the raw material 
varies or the market for the main product fluctuates, and therefore not 
dependable as a self-contained source of power. A power-supply system 
in these cases affords a means of marketing what is otherwise a waste- 
product. 
Other sources of power of a different character from the foregoing, which 
must inevitably remain unutilized with absence of a power-supply system, 
are water-power sources the flow of water in which is too variable or 
inadequate as a main or principal source of supply. It frequently occurs, 
that a water-power source can be cheaply developed, but that the provision 
of storage necessary to make it a dependable source is not possible except 
at great expense. Provided, however, that a power system is already 
established with one or more reliable sources from which the power can be 
regulated and controlled, such sources may very conveniently be utilized 
as auxiliary supplies, the deficiencies of which are made good from the 
principal source or sources. 
Thus the establishment of a power-supply system not only affords a 
means of supplying cheap and efficient power, but also enables power to 
be absorbed and utilized which, in its absence, runs to waste because there 
is no local use for it, whilst it is not dependable enough to form an inde¬ 
pendent source for power-supply purposes. 
The Establishment of New Industries. 
It has been shown how a power-supply undertaking affords a means 
of utilizing waste gases from industrial operations, and also of utilizing 
power derived from inferior coals which will not bear the cost of transport, 
or of peat, which must be treated locally if treated at all. And inasmuch 
as the utilization of such material is only possible, or at least is very much 
facilitated, by the existence of an electric-power system, they constitute 
examples of industries created by its establishment. It has also been 
shown how the provision of a cheap and unrestricted supply of electricity 
facilitates the growth of existing industries. In addition to this, however, 
it promotes the establishment of new industries which are dependent upon 
electricity as a thermal or electro-chemical agent. An example of this may 
be found in the neighbourhood of Christchurch, where the Lake Coleridge 
supply has made it possible to put into operation a plant for the manufacture 
of hydrated oxide of iron from discarded iron cans and cases, and where 
projects for the manufacture of caustic soda, hydrochloric acid, and for 
making steel castings out of steel scrap are well advanced. 
Other examples of the same class of industry are the manufacture of 
calcium carbide, calcium cyanamide, and nitric acid. Such commodities, 
are usually manufactured on a large scale in localities where harbour 
facilities are obtainable in conjunction with cheap water-power development. 
On the other hand, since they form the base of many industries and are 
in themselves very unsuited for transport purposes, it is often found 
advantageous to manufacture them in localities where the market exists 
rather than to carry them long distances, provided that the raw material 
is obtainable together with a supply of electric power at reasonable rates, 
even although the cost of power may be considerably higher than in the 
former case. An opportunity exists of establishing an industry of this 
kind in conjunction with the freezing industry by employing the electric 
power to the full in a chemical industry during the slack season of the 
