98 [April, 1902.] 
IMPERIAL INSTITUTE JOURNAL. 
Vol. VIII. No. 88. 
small, and the only feature of note is the fact that Western Australia has more than doubled 
its output since the previous year. This was due to the opening up of the Collie coalfield, 
where three collieries are now at work. Of foreign countries the largest coal producers are 
the United States and Germany, which furnish 244,901,839 and 149,788,256 metric tons 
respectively. 
Iron . — The amount of iron ore obtained in the colonies is small and the total shows a 
decrease, owing to a diminution in the home production. Out of a total of 4,987,641 
metric tons the colonies only supplied 245,806 tons, this being a slight increase on their 
contribution of the previous year. The output from Newfoundland showed a considerable 
increase, but that from Canada was much less than in 1809. The countries producing more 
iron than the United Kingdom are the United States and Spain, their outputs being 
14,014,475 and 5,626,410 metric tons respectively. 
Copper . — The British Empire does not produce a large quantity of copper, its output 
being only one-thirteenth of the total, but the amount was considerably increased during 
1900, owing probably to the high price of the metal. The quantity rose from 34 , 5°7 metric 
tons in 1S99, to 41,456 tons in 1900, and for this increase Canada and Tasmania were 
chiefly responsible. In the latter colony the most important source of copper ore is the 
Mount Lyell Mine on the west coast, and the output increased from 6,157 metric tons in 
1899 to 9,766 tons in 1900. The United States is by far the largest producer of copper, 
yielding 275,000 metric tons in 1900. 
Lead .' — The amount of this metal supplied by British Possessions was increased in 1900 
by over 20,000 metric tons, owing to a large increase in the Canadian production, and 
formed a little less than one-tenth of the world’s supply. Great Britain also supplied 
24 , 755 metric tons, and the other chief contributor is Tasmania with an output of 13,347 
tons. The world’s chief producers are the United States, Spain and Germany, with out- 
puts of 245,757, 203,744 and 121,513 metric tons respectively. 
Tin . — Of this metal the British Empire contributed more than five-eighths of the world’s 
supply, the chief source of ore being the Federated Malay States, which supplied 43, 1 23 
metric tons of tin out of a world’s total of 80,643 metric tons. The greater part of the ore 
raised there is treated at Singapore, which has now the largest tin-smelting works in the 
world. Great Britain produces more than any of the other colonies and the Tasmanian 
output has slightly declined. Of foreign countries the chief producers of tin are the Dutch 
East Indies, Bolivia and Siam. 
Zinc . — The production of this metal in the British Empire underwent a decrease of 
nearly 50 per cent, during the year under review, owing to a drop in the output of New South 
Wales from 16,272 metric tons in 1899, to 4,100 tons in 1900, Great Britain itself pro- 
duced 9,211 tons, but the supplies obtained from the other colonies are insignificant. The 
world’s chief producers are Germany and the United States, with outputs of 153,35° an( l 
112,419 metric tons respectively. 
ALUMINIUM AND ITS ALLOYS. 
The production of pure aluminium upon a commercial scale has opened a wide field for 
investigation, since not only the metal itself but also its alloys possess properties which 
render them of great value for many purposes. The metal gives rise to an enormous number 
of alloys, some of which, containing one or two per cent, of other metals, combine the 
lightness of aluminium with greater hardness and strength, while, on the other hand, many 
metals are greatly improved for certain purposes by the addition of from one to ten per cent, 
of aluminium. The former may be classed as light aluminium alloys; the latter as heavy 
aluminium alloys. At the present time the metal and some of its light alloys are being 
largely used, instead of copper, as electric conductors for long distance transmission ; and 
consequently the determination of the tensile properties, the change in length due to 
differences of temperature and the electrical conductivity of these was of considerable 
importance, especially as the addition to aluminium of copper, zinc, nickel and iron, 
in quantities up to two per cent., increases the tensile strength at the expense of the 
conductivity. Prof. E. Wilson, M.I.K.E., of King’s College, London, has carried out such 
an investigation on 24 light aluminium alloys and gave an account of his results, some of 
which had already been published, at a recent meeting of the Society of Arts (fourn. 
Soc. Arts, Vol. L, p. 54 ). 
The purest commercial aluminium contains about 99'5 per cent. of. the metal, the 
remainder consisting of iron and silicon, and its specific gravity at 15 0 C. varies from 2-5 6, 
when cast in sand, to 271 when hammered or drawn. Its colour is found to vary with the 
method of casting ; if cast in chill moulds and cooled quickly or in green sand at a low 
temperature the metal has a bright white colour nearly like that of silver, but if cast too 
hot in dry sand the colour is grey, like lead, or bluish like zinc. It can be melted in 
plumbago or sand crucibles without becoming brittle or taking up silicon, provided the 
temperature does not greatly exceed its melting point, 626° C., and when used for castings 
the shrinkage is o - 2 in. to the foot, as compared with 0.187 in- f° r copper. The annealing 
must be done in a closed muffle, as it is very essential that the metal should not come in 
contact with the open fire. The hardness depends upon the purity, the purest metal 
being the softest, and ordinary 98 per cent, aluminium about as hard as copper, but may be 
increased by working. 
The results of the tests are summarised in the following table, so that the influence of the 
different metals added can Lie easily seen, while the corresponding figures for hard-drawn 
copper are added for comparison. The breaking load and limit of elasticity were in each 
case determined with wire of *126 in. diameter. 
Co-efficient 
Limit of 
elasticity 
in !b. 
Composition. 
Specific resist- 
Tempera- 
of linear 
Breaking 
- — • 
ance in legal 
tlire co- 
expansion 
load in lb. 
ohms at I3°C. 
efficient. 
between 
per sq. in. 
1 6° & ioo° C. 
per sq* in* 
Copper . . . 
. _ _ 
i -696 x 10"^ 
„ 
■OOOOI7 
62,700 
"0 
0 
1 
! fr 
1 Containing *31 p.c. ) 
■ iron & ‘14 p.c. 
( silicon . . . . ) 
-6 
Aluminium . 
2762 X IO 
•OO393 
■OOOO23 
2S,200 
19.376“ 
Alloys. — 
Copper . . . 
I ‘5 to 2 p.c. of copper 
3.3 XIO 
’OO30 
’OOOO24 
40,000 
33,000 s 
Nickel 
2 ”2 p.c. of nickel . . 
• — - 
— 
— 
58,600 
20,300 
Nickel-Copper . 
f r’29 p.c. nickel & ) 
1 I'oS p.c. copper J 
-6 
3 '41 x 10 
■OOI78 
•OOOO252 
45,900 
36,600* 
Nickel-Iron . 
f 1*39 p.c. nickel & ) 
1 2 '6 p.c. iron . . f 
-6 
3*24 X IO 
•OO32 
*0000222 
42,200 
24,400 
Nickel-Zinc . . 
| '83 p.c. nickel & ) 
) - 9 p.c. zinc . . J 
-6 
3-03 X IO 
— 
— 
— 
5 
Iron-Manganese 
f '56 p.c. iron & r.78 | 
\ p.c. manganese . J 
— 
— 
— 
35.3°° 
24,400® 
1 Percentage extension of '10 with 7 'a tons applied per sq. in. 
9 Percentage extension of ’19 with 7 '2 tons applied per sq. in. 
3 Little is gained in tensile strength by increasing the copper from 1 ‘5 to 2 '5 per cent. 
4 Percentage extension of '146 with 7^2 tons applied per sq. in. 
B Five of these alloys were tested; the maximum breaking load was 36,000 lb. , and the limit of 
elasticity remained low. 
fl Specific resistance was high. 
In addition to the above some zinc and copper-zinc alloys were also tested. In the 
zinc alloys the conductivity was greater than in those containing copper in the same 
proportion, and the co-efficient of expansion fell slightly with increase of zinc, whereas it 
rose with increase of copper ; the alloy containing 2 per cent, of zinc has a lower conductivity 
than that containing only 1 '2 per cent. The two copper-zinc alloys examined did not 
exhibit any noteworthy properties. 
With reference to the use of aluminium for electric transmission it will be seen from the 
above figures that, as the specific gravity of copper is 3*37 times that of aluminium, the 
conductivity of equal weights of aluminium and copper is as 2 to I, or for equal conductivity 
half the weight of the former would be required. The ratio of the diameters of an aluminium 
and a copper wire of the same total conductivity is as 1 *27 to 1, or of the cross-sectional area as 
1 ‘61 to I, and at recent prices the cost is slightly in favour of aluminium, besides which the 
reduction in weight involves a great saving in transport and for overhead wires fewer and 
lighter poles are required. When aluminium was first utilized as an overhead conductor some 
difficulty was experienced in several places owing to excessive breakages, but with improve- 
ments in manufacture this appears to have been entirely done away with and the most 
recently erected lines have successfully withstood very severe storms. As far as the effects- 
due to gravity and temperature are concerned, aluminium is just as advantageous as copper, 
since its lightness and greater percentage extension counterbalance the effect ol its greater 
linear expansion, and, in fact, with regard to the elastic limit the factor of safety is greater 
than in copper under the same conditions. For small single wires where great tensile 
strength is needed the nickel-copper alloys, which have a limit of elasticity exceeding that 
of copper, might he employed with advantage, though the conductivity is lower than that of 
pure aluminium, but for large, single- or stranded conductors the latter should prove 
sufficiently strong. Whether overhead aluminium wires are liable to corrosion on exposure 
is a matter of great importance, and careful observations are being made at many places in 
order to decide this. Professor Wilson exhibited a specimen which had been in use for four 
years at Foyers and was very little affected, but, on the other hand, some experiments 
made by Mr. Kershaw (Imp. Inst. Journ., Vol. vn., p. 41) appear to show that the 
air of manufacturing towns has a much greater influence. Up to the present, however, no 
serious action has been observed on any of the established lines. 
The employment of aluminium has in the past presented one great drawback, viz., the’ 
difficulty of soldering it, and many methods have been introduced for overcoming this, such 
as the use of a sleeve-joint for wires, a method of electric welding, and the Cowper-Coles 
process, of which details have not been given. The difficulty appears to be chiefly due to the' 
slight film of oxide which forms upon the surface of the metal on exposure to air, and which' 
must be broken up by scratching with a wire brush, while the surface is covered with the 
molten solder. If this procedure is followed the operation becomes quite easy with a solder 
of the following composition : — 28 parts of block tin, 14 of phosphor-tin (10 per cent. phos- 
phorus) 3 '5 of lead, and 7 of spelter. 
The chief heavy aluminium alloys at present in use are the aluminium bronzes, which 
usually contain from 8 to 12 per cent, of aluminium and 92 to SS per cent, of copper. These 
possess a golden colour, are non-corrodible, and as strong as steel, being extensively employed 
for propeller blades, rudder frames and in hydraulic work. The breaking load varies ftorm 
34 to 44 tons per square inch, according to the composition of the alloy, and they have a high) 
elastic limit and transverse strength. For forgings or stampings four classes of bronze are recom- 
mended, containing respectively 10, 7 " 5 > 5 > anc ^ 2 '5 P er cent, of aluminium (the rest being 
copper) ; the specific gravity of these varies from 7'6 to 8 7, and the tensile strength from 30 
to 20 tons per square inch. 
THE WORK OF THE GERMAN COLONIAL ECONOMIC 
INSTITUTE. 
The colonies and dependencies belonging to the German Empire, although comparatively 
insignificant in total area and possessing at present but a small volume of trade, bid fair in 
the future to become important commercial centres, owing to the care with which their 
resources are being surveyed with a view to ultimate utilization to the greatest advantage of 
the colonies concerned. It will be sufficient in this connection to mention the systematic 
mineralogical and botanical surveys now being made in German West and East Africa, and 
the establishment in the latter colony of a State Department charged with the thorough investi- 
gation of new natural products of all kinds and the determination of their exact commercial 
value. 
This anxiety to develop commercial relations with the colonies is not, however, confined' 
to the German Government, as is shown by the formation a few years ago of the Kolunial- 
Wirtschafiliches Komitee of Berlin, on the initiative of a number of gentlemen connected with 
academic institutions in Germany. This body, which receives no financial help from the' 
Government, carries out in Germany work similar to that of the Scientific and Technical 
Department of the Imperial Institute and of Kew Gardens, but of course on a- very muchi 
smaller scale. 
Its work is organised by an elected executive council, and the funds are provided bv 
subscriptions from members who, in return, have the privilege of attending certain meetings 
and of receiving free the official publications of the society. 
Au idea of the work cafried out by this body may perhaps best he obtained from the 
yearly report issued for 1900-1901. This commences with a concise statement of colonial 
development during the year, giving particulars regarding new companies formed for the 
exploitation of colonial products, dividends paid by companies already at work, and other 
similar matter. 
The society employs a chemist and a botanist who examine and report upon products 
submitted by colonial correspondents. Among the materials so examined during last year may 
be mentioned rubber derived from a species of Ficus occurring in the Cameroons, gums from 
German W. Africa, which were found to be excellent substitutes for Soudanese gum, various 
gutta-perchas collected in S. America, tobacco cultivated in the Cameroon district, and maize 
and potatoes from German South-West .Africa. In addition a number of substances were 
submitted to commercial experts, such as divi-divi pods from S.W. Africa, which were valued 
at 10s. per cwt. , ‘kapok 5 a fibre derived from Calotropis procera (this material has already 
been investigated in the Scientific Department of the Imperial Institute), the gums already - 
referred to, which do not appear to have greatly impressed the experts to whom they were' 
sent, a specimen of Manilla hemp from Ponape, sisal hemp from New Guinea and ramie: 
fibre from the Cameroons. 
The chemical investigations so far undertaken appear to be of a very superficial nature, 
and comparatively few substances of unknown character are submitted for examination, a 
condition which is perhaps due to the fact that the German colonies are of recent acquisition, 
and attention is at present being devoted rather to products already well known than to- 
materials for which some application may eventually be found. The work, therefore, differs 
somewhat in character from that of the Scientific Department of the Imperial Institute, where 
in addition to the examination of commercial products such as those mentiond above, which 
is constantly going on, investigations into more difficult subjects such as the invention of 
processes for the utilization of tan-stuffs, resins and gums which in their natural conditions- 
present some objectional features from a manufacturer’s or consumer’s point of view, have' 
