1918.,] The N.Z. Journal of Science and Technology. 
185 
they appointed to deal with the question of power generation and transmissions. In 
submitting this report they desire me to make the following observations :— 
The question of the conservation of coal, so far as it falls within the reference to 
that sub-committee, is the question of economy in the use of coal through supplying 
electricity for power and other forms of energy. The consumption of coal involved 
is so large, and the economy in the use of it which can be effected is so great, that it 
is a matter of grave national importance that action should be taken without delay. 
Indeed, it is scarcely possible to exaggerate the national importance of the problem 
of a technically sound system of electrical supply, because it is essentially one with 
the problem of the industrial development of the country, which largely depends upon 
increasing the net output per head of the workers employed in the industries in which 
power can be used. 
In order to solve the problem it is necessary first to define the essential conditions 
of electrical generation and distribution which together result in the cheapest supply, 
and this is done in the sub-committee’s report. 
As regards generation, the essential conditions of economy laid down in that report 
are that the generating plant should be large, and erected on sites where water is 
plentiful and transport facilities good, or fuel close at hand. The sites must be ample, 
so as to allow not only for the large subdivided generating-stations, but also for the 
erection of coal by-product recovery plant, and, in some cases at any rate, for the 
ancillary purpose of erecting plant for electro-chemical processes which have not yet 
been developed in this country. 
As regards distribution, the essential conditions of economy laid down in the report 
are that each district of electrical supply under a single authority should be a large 
area, with the greatest possible variety of electrical requirements, and including 
populous centres of industrial activity. All these requirements should be provided 
for by means of an interconnected power-distribution system, tapping all existing 
sources of power—such as waste gas and heat—and delivering electrical energy wherever 
it is needed, thus making possible the use of much coal now wasted or left in the pit 
because it will not stand transportation. 
Finally, both as regards generation and distribution, it is essential that the whole 
system should be subject to the general supervision and control of a single body of 
Electricity Commissioners. 
To realize these conditions a comprehensive policy for the whole country is neces¬ 
sary ; and, fortunately, such a policy is practicable in this country to a greater extent 
than elsewhere, on account of the compact nature of our industrial areas and their 
close proximity to each other. But the Coal-conservation Sub-committee feel that 
they must draw special attention to the necessity of the policy being national in 
character, because, as the report shows, the historical development of electric supply 
in this country during the last thirty years has been local in principle and character, 
and the resulting position will have to be superseded. 
It should, however, be kept clearly in mind that whatever conflict there may be 
between the interests of the local electrical authorities which exist at present and the 
interests of a comprehensive scheme, there is no conflict in this matter between the 
interests of the local community and those of the nation as a whole. The interests of 
every individual user of electrical energy are bound up with the establishment of a system 
which will deal comprehensively and upon right lines with the gradual development 
of all the electrical requirements of the community. 
It is unfortunately the case that the working - out of such a scheme of power- 
distribution is complicated and hampered by the necessity of utilizing existing plant 
to the best advantage. The Coal-conservation Sub-committee think, however, it 
should not be further hampered by mistaken policy of the past, except in so far as 
justice requires that fair compensation should be paid for existing rights and equitable 
provision made for the ultimate liquidation of existing financial obligations. Subject 
to these limitations, the new scheme should provide for a clear field for the develop¬ 
ment of a comprehensive system of electrical supply upon lines which are technically 
right and commercially sound. 
A supply of this important publication has been ordered by the Public 
Work' Department, and will be available for distribution to persons 
specially interested. E. P. 
Foaming of Boiler-waters, by W. A. Hargreaves. Bulletin of the De¬ 
partment of Chemistry, South Australia, No. 5, 75 pp., 1917. 
Foaming is-defined as ’‘the phenomenon exhibited by some waters of 
producing a very large number of small bubbles when boiled. The bubbles 
are so abundant as to occupy a large volume above the liquid, and in 
