Vol. VIII. No. 96. 
IMPERIAL INSTITUTE JOURNAL. 
[December, 1902.] 
3 21 
0*034 p.c. of sulphur, o*oi 6 p.c. of phosphorus and 2*24 of insoluble matter. Drill hole No. 3, 
located 440 feet from this, was put down vertically for 72 feet, iS feet being soil. The ore 
contained 5473 p.c. of iron, 0*015 p.c. of sulphur, 0*017 p.c. of phosphorus, and 8*40 p.c. of 
insoluble matter. 
TASMANIAN TIMBERS. 
The forest areas of Tasmania are still of considerable extent, owing to the fact that the 
island has not yet attracted a population so dense as that of the neighbouring continent, so 
that fewer clearings for fanning operation have been made, and less attention has been 
paid to the exploitation of the forests for timber. In a paper recently contributed to the 
Royal Society of Tasmania, and now printed in pamphlet form, Mr. A. O, Green gives the 
results of a series of determinations of the mechanical properties of the principal timbers of 
the island, supplemented by notes on their working qualities, and on the botany of the trees 
producing them, from which a summary may well be given in this Journal, as a continuation 
of similar articles on Colonial timbers which have been from time to time published in these 
columns. The Tasmanian forests present the usual features of the forest areas of these 
latitudes, viz., an underlying growth of ferns, succeeded by tree ferns and scrub trees over- 
topped by the principal timber trees belonging to the eucalyptus and myrtle class. The chief 
eucalyptus trees are : — 
Products obtained. 
Eucalyptus globulus 
Eucalyptus stuartiana . 
Eucalyptus MUelleri 
Eucalyptus obliqua 
Eucalyptus amygdalina 
Eucalyptus Immastoma 
Eucalyptus regnatts 
Eucalyptus viminalis . 
Eucalyptus sieberiana . 
Eucalyptus gunnii 
Eucalyptus coriacea 
Blue gum 
Red gum 
Mueller’s gum . 
Stringy bark . 
Peppermint 
Gum-topped stringy bark , 
Swamp gum 
White or manna gum 
Iron bark 
Cider gum 
Weeping gum . . » 
Timber and essential oil 
Timber 
Timber 
Timber, tanning-bark and 
kino 
Timber and essential oil 
Timber 
Timber 
Timber and eucalyptus honey 
Timber 
Timber and fermentible sap 
Timber 
The chief acacias are ; — 
Acacia melanoxylon. Blackwood. This tree is widely distributed in clumps and grows 
to a height of eighty feet, with a diameter of two to four feet. The timber is brown or red 
in colour, resembling walnut and pencil cedar ; it is used for cabinet-making and carriage 
building. 
Acacia dcalbata. Silver wattle. The timber of this tree is occasionally used for furni- 
ture making, but the bark is its most important product and is employed for tanning, as is 
also the case with the black wattle ( Acacia decurreus ). 
The so-called Myrtle ( Fagus cunninghamii ) closely resembles the European beech in 
the character of its timber, but, owing to the occurrence of the tree in at present inaccessible 
districts, it is not much used. 
Pine trees are of less importance in Australasia than in other countries, their place being 
taken by eucalyptus. Five members of this class are known in Tasmania, viz., Huon pine 
( Dacrydium franklinii ) f King William pine ( Athrotazus selaginoides ), also knowm locally 
as pencil cedar ; Celery top pine ( Phyllocladus rhotnboidalis) , Oyster Bay pine ( Frcnela 
rhomboidea), which produces a useful timber, and in addition a fragrant resin, said to resemble 
sandarac and to be suitable for varnish making, and sassafras ( Atherosperma moschata ), 
which yields a soft light timber suitable for carving, whilst from the bark and leaves an 
extract employed locally as a tonic is prepared, 
Among the smaller * * scrub ” trees are 
Melaleucia ericccfolia {“tea” tree). The leaves of this tree contain, like the allied 
species M. minor , an essential oil which has not yet been chemically examined. 
Casuarina species. The timbers of these small trees are, owing to their rich and varied 
colourings, especially prized for cabinet-making and veneer-cutting, 
The mechanical properties of the commonly-occurring timbers, together with their 
European and American analogues, are given in the following table t— 
Mean weight 
per cubic foot. 
Transverse 
strength. 
Crushing stress 
along the grain. 
Crushing stress 
across the grain. 
L W 
lb. 
4 bd 3 
Ash (English) 
47 
2,130 
9,000 
— 
Beech (English) . 
43 
L 794 
8,500 
Yellow deal .... 
3 6 
1,600 
6,000 
626 
Oak (English) 
54 
1,788 
8,300 
2,316 
Blue gum (dry) . 
60 
2,706 
9,000 
4,500 
Stringy bark (dry) 
57 
3.273 
8,000 
4,50° 
Gum-top stringy bark (dry) . 
5 ° 
L 958 
— . 
— 
Swamp gum (dry) 
54 
2,367 
— • 
— . 
Peppermint (dry) . 
59 
1,623 
— 
— 
White gum (dry) 
46 
1,717 
— 
— 
Myrtle (dry). 
47 
2,804 
7,000 
4,500 
Leatherwood (dry) 
45 
3,258 
8,000 
6,000 
Celery-top pine (dry) . 
42 
2,225 
7,000 
1,000 
THE CULTIVATION OF CASTILLOA ELASTICA IN JAVA. 
In the previous number of this Journal (Vol. vni,, p. 292) an account was given of 
some experiments carried out in Central America by Dr. C. O. Weber on the latex and 
rubber of Castilloa elastica, and the information contained therein may be supplemented by a 
brief description of other experiments on the same subject which have been made by Dr. 
Spire in the Dutch East Indies. ( The India Rubber World , N.Y., Vol. 27, p. 43). 
It will be remembered that Koschny, after a detailed study of the Castilloas in Central 
America, came to the conclusion that there are three varieties of C. elastica , differing con- 
siderably in rubber-yielding power, and he thought that it must have been the worst of these, 
C. elastica , var. rubra , which had been planted in the East Indies and given such discouraging 
results in some cases. Dr. Spire, however, after a careful study of Koschny’s monograph on 
the subject, was not able to determine the identity of the particular variety which was 
introduced into Java. All the Castilloas there have resulted from two seedlings which were 
planted in 1883, and from the seeds yielded by these a very large number of trees have been 
obtained, some of which have now attained a height of 65 feet and a circumference of over 
50 inches. 
The experiments on the yield of latex and rubber were carried out by Dr. Spire in May, 
1901. The tappings were made by a series of V-shaped cuts, extending from 10 to 15 feet 
up the trunk and connected at their bases by a single vertical incision. The latex, which 
0/ 1 ^ 
flowed freely, was at times very white and at others had a brownish tinge, while some incisions 
only yielded a blackish fluid which exuded very slowly. The latex obtained by Dr. Weber 
at Las Cascadas was in the form of a thick cream, which did not flow readily, and in this 
case a continuous spiral incision round the trunk was found preferable to the method of 
tapping described above. 
The rubber was separated by diluting the latex with water and allowing it to stand, 
when the rubber globules slowly rise to the surface, leaving a clear serum which is drawn off 
from time to time. The rubber globules finally cohere to form a cake, which is removed at 
the end of the eighth day and the liquid remaining in it is extracted by pressure. 
The weight of the rubber obtained from six trees which were each tapped twice was as 
follows : — ■ 
First tapping. 
Second tapping. 
Total. 
grams. 
grams. 
grams. 
First pair of trees 
28 
130 
158 
Second ,, ,, . 
. 220 
290 
510 
Third ,, ,, 
125 
205 
330 
Total . 
373 
625 
99S 
The two trees which gave the largest yield were planted in 1S84 and were therefore 
about 7 years old at the time. The result in dry rubber was 340 grams for the first tapping 
and 600 grams for the second, or a total of 940 grams, from the six trees, being an average 
yield of about 5*5 oz. The average yield of rubber from a tree S years old is given as 6*25 
oz. This is a much lower yield than was obtained by Dr. Weber from trees of the same age 
(viz, 14*2 oz.), but is better than the result of Dr. Trimen’s experiments in Ceylon, which 
gave a maximum yield of only 4*3 oz. This difference may be due, as Koschny thinks, to the 
East Indian Castilloa being an inferior variety, or, if not, it must be caused by differences of 
climate and soil. 
In general practice the tapping and collection of the rubber is done by Malays, who are 
carefully supervised to prevent the destruction of the trees, and the men are required to 
deliver about 1 lb. of rubber daily. When brought to the factory the rubber is cleaned by 
washing in running water and is then dried by exposure to the air in the shade. The cost of 
collection, purification and packing amounts to about 3 florins per picul (132 lb.) and the 
price obtained for the rubber in 1900 was 300 florins per picul, so that even w r ith the low 
yield the industry is a profitable one. 
The Castilloa elastica of Java will not thrive in moist and swampy land, but is suited 
by a high and dry situation, through the altitude must not be too great, as experiments made 
at a height of 3,500 feet were unsuccessful. 
Castilloa elastica is also being cultivated in Sumatra, where it yields an abundant latex, 
which, however, appears to contain a large percentage of resin. 
THE UTILIZATION OF ATMOSPHERIC NITROGEN. 
The question of the world’s supply of fixed nitrogen, and its bearing on the possibility of 
raising sufficient wheat to satisfy the future requirements of the bread-eating peoples, were 
brought into prominence by the presidential address of Sir William Crookes, at the British 
Association in 1898, and have continued to excite considerable interest. At the present time 
Chili saltpetre is the chief source of available nitrogen, but it is stated that at the present rate 
of consumption there is not more than 30 years’ supply of this available, so that it is evident 
that some fresh source must be looked for in order to meet future needs. It is well known 
that nitrogen can be made to combine directly with oxygen by means of an electric arc, with 
the formation of oxides of nitrogen, which can be afterwards converted into nitric acid of 
nitrates, which can be afterwards converted into nitric acid or nitrates, and Lord Rayleigh has 
shown that with cheap power available nitrates could be made by such a process at less than 
the present cost. It was announced some time ago that the manufacture of nitric acid and 
nitrates from atmospheric nitrogen by such a method was to be commenced at Niagara, and 
recently some particulars of the apparatus which is to be employed have appeared in the 
technical papers {The Electrical Review , VoL. 51, p. 721). 
For carrying out the process on a large scale it has been found necessary, in order 
to secure efficiency, to employ a large number of small arcs so as to present a very large surface 
for a small expenditure of power, and for this purpose a special apparatus has been designed. 
It consists of a cylindrical metal box, five feet in height and four feet in diameter, having on 
its inner surface six vertical rows of fixed contacts, 138 in all, each of which terminates in a 
platinum wire. Inside this is another cylinder, capable of revolution round a vertical axis, 
and furnished with similar contacts on its outer surface, the two series of platimum points 
being i/25th of an inch apart when opposite. The contacts of the outer cylinder are 
connected to the positive pole, and those of the inner to the negative pole of a dynamo 
generating direct current at 8, 000 or 10,000 volts, so that as the inner cylinder revolves the 
negative contacts approach the positive and arcs are formed, which are then drawn out, and 
finally extinguished as the distance between the points increases. The inner cylinder makes 
500 revolutions per minute, so that each contact is made and broken fifty times per second, 
giving a total of 6,900 arcs per second. Each arc receives about *005 ampere, and lasts for 
about one 20,000th of a second. When the arcs form there is a sudden increase in the 
current, and short-circuiting is prevented by inductance coils in series with the arcs. These 
retard the current for about one 40,000th of a second, and during the remainder of the period 
as the arc is drawn out and about to break their effect is to prolong it. When current at 
8,000 volts i3 used with an average of *005 ampere per arc, the arcs are drawn out to four or 
six inches in length. 
Air, or preferably a mixture of oxygen and nitrogen in equal parts, is circulated through 
the apparatus, being renewed at the rate of three or four cubic feet per minute, and on leaving 
it contains about 2*5 per cent, of oxides of nitrogen. If nitric acid is required, the latter are 
absorbed by passage through a scrubber tower filled with coke down which water is allowed 
to percolate, and for the production of alkaline nitrates the water is replaced by a solution of 
caustic alkali. 
The theoretical yield is 1 lb. of nitric acid per 7 H.P. -hours, and though the practical 
efficiency of the apparatus is not given, it is stated that the results obtained at the experi- 
mental station have been very satisfactory. The works at Niagara are nearly completed, and 
operations will be commenced at an early date with 2,000 h.p., so that it will soon be possible 
to estimate the commercial value of the new process. 
THE CULTIVATION OF FIBRE PLANTS IN MAURITIUS. 
The only fibre plant which has been hitherto grown in Mauritius on the large scale is 
Furcraea gigantea , commonly called 11 aloes vert ,” but of late years its cultivation has been 
neglected, although the fibre is still prepared and exported. Of other fibre plants, Agave 
americana occurs in Mauritius in the wild state, but less abundantly than Furcraea , whilst 
several years ago Agave rigida v. sisalana was introduced. 
When Furcraea gigantea grows under favourable conditions such as occur in Mauritius, 
it undergoes rapid multiplication by means of the numerous small plants produced on the 
flower stalk which fall to the ground and take root. Owing, however, to the mutual 
proximity of the plants thus produced, the yield and quality of the fibre is not such as could 
obtained from a plantation in which the plants were placed at a convenient distance from 
