April 6, 1882] 
NATURE . 
527 
offered by the map, nor of his advantage in possessing so 
extensive a knowledge of mineralogy. He might as well 
have used a map one-fourth the size, which would have 
given all the detail he has published, in sufficient minute- 
ness for the illustration of his papers. It is extraordinary, 
for instance, that not the slightest indication of structure 
is given, over the whole of the area of the older gneiss, 
No one can tell from the map, that the strike of this rock 
is nearly at right angles to that of all the other rocks. It 
is equally remarkable, that where indications of structure 
have been inserted, they are, in some cases at least, 
obviously imaginary. Lines of fault are recklessly drawn 
along the bottom of lakes, where they could not possibly 
have been observed, and where, as they coincide with the 
strike of almost vertical beds, they would be extremely 
difficult to prove, even if the rocks were visible all the 
way. It is hard to understand why they should -have 
been inserted, unless to support some theory of lake- 
formation. 
Besides the more detailed mapping of the Durness 
and Assynt areas, the map makes a few additions to our 
knowledge, such as a greater extension of the Cambrian 
or Torridon sandstone, and the existence of a solitary 
outlier of Old Red Sandstone in the centre of Suther- 
landshire. 
The writer of the present notice has not hadan opportunity 
of visiting the ground, but he is under the belief that the 
west of Sutherlandshire exhibits on a great scale the 
phenomena of glaciation. One would naturally look for 
indications of the moraines and other traces of old 
glaciers on so large a map, but these superficial markings 
are likewise conspicuous here by’ their absence. Only 
one moraine is marked by Dr. Heddle. Is this the only 
one in the county? 
The index of colours is a model of confusion. The old 
gneiss is placed at the top, then in succession come the 
rest of the rocks up to the Old Red Sandstone, followed 
in reverse order by the Upper Oolite and lower members 
of the Jurassic system, Trias, the Durness limestone, 
Syenite, Granite, Porphyry, and Eruptive rocks, A 
more serious defect still is the want of acknowledgment 
of the sources of information from which the map has 
been largely compiled. The maps and papers of Maccul- 
loch, Murchison, Nicol, Geikie, and Judd, have all been 
made use of, and this should have been conspicuously 
stated on the map itself. 
OUR BOOK SHELF 
A Year in Fiji; or, An Inquiry into the Botanical, Agri- 
cultural, and Economical Resources of the Colony. By 
John Horne, F.L.S., Mauritius. (London: for Her 
Majesty’s Stationery Office, 1881.) 
THIS report gives an extremely interesting sketch of the 
food products of the Fijis. Mr. Horne’s tour, which 
occupied a year, was made in 1877, and he was specially 
commissioned to report on the sugar culture in these 
islands, 
Beginning with an account of his tour through the dif- 
ferent islands of the group, we have then a chapter on the 
chief peculiarities of their flora, The flora he considers 
still very imperfectly known, and he was enabled to add 
some 300 species to Dr. Seeman’s list. Here we find 
ourselves obliged to protest in the strongest possible way 
against the extremely objectionable manner in which the 
scientific names are printed in this report: the initial 
letters of all the generic terms are printed in lower case, 
and not, as is the universal custom, with a capital letter ; 
and thus not only the usefulness, but the appearance of 
the book, is interfered with. We acquit the author of ' 
blame in this matter, for he may never have seen the 
proofs; but the reader for press, with the list of Fiji 
plants which appears on page 256 before him is without 
excuse. 
Fruit is plentiful in Fiji, and, might with advan- 
tage be exported, especially bananas, pine-apples and 
oranges. Attention is called to the necessity of re-foresting. 
Of the agricultural products, mention is made of copra, 
sugar, cotton, maize, tobacco, and coffee. Of copra, the 
dried kernel of cocoa-nuts, there was exported in 1878 
122,194/. worth, but little oil was made, the copra paying 
better. The sugar crop is steadily on the increase: for 
1880 it was estimated to produce 60,000/., and when fully 
developed, Mr. Horne estimates a possible yearly make 
of about 200,000 tons. Coffee-trees thrive well, and the 
coffee export in time will be second only to sugar. Cotton 
is being displaced by the sugar-cane. The trees yielding 
caoutchouc in Fiji are Apocynaceous, belonging to the 
genera Tabernemontana and Alstonia. The Fijians col- 
Ject the juice which exudes from the broken leaves and 
branches in their mouths. Several mouthfuls are then 
rolled into a ball, and the juice congeals so quickly that 
it requires very little working with the fingers before it is 
dry and ready for the market. Samples sent to England 
were priced as high as 2s. 6¢.a pound. Sandal-wood is 
becoming scarcer and dearer each year in Fiji ; in 1878 it 
was worth 10/, a ton. 
In an appendix we find a series of propositions for a 
forest crdinance for Fiji, which, carried into effect, would 
no doubt be of great service to this British colony. 
LETTERS TO THE EDITOR 
[The Editor does not hold himself responsible for opinions expressed 
by his correspondents. Neither can he undertake to return, 
or to correspond with the writers of, rejected manuscripts. 
No notice is taken of anonymous communications, 
[The Editor urgently requests correspondents to keep their letters 
as short as possible. The pressure on his space is so greai 
that it ts impossible otherwise to ensure the appearance even 
of communications containing interesting and novel facts. | 
On a Perpetual Form of Secondary Cell 
I HAVE succeeded, after many fruitless attempts, in discover- 
ing an indestructible material which can be substituted for lead, 
as the negative or oxygen-bearing plate of the Faure accumu- 
lators, without sacrificing any of the extraordinary good qnalities 
which that excellent form of secondary couple possesses, excepting 
only its cheapness of construction. 
The only sub:tance which I have yet found to be such an 
effective substitute for the lead-plate, is platinum-foil, which has 
been coked at a high heat with lampblack for some days in a 
pottery kiln, until its smooth surface becomes thereby roughened 
with a dull drossy coat. To whatever assimilation of metalloids 
from the pure lampblack, or from the kiln-furnace gases, this 
surface-alteration of the clean platinum is due, it seems probable 
that the electrolytic oxygen in the charging process removes the 
contamination, leaving the platinum-surface in the fine state of 
nearly molecular sub-division necessary for forming conducting- 
contact with the ozone-, or oxygen-imbued dioxide. For the 
result is a current of very nearly the same copious quantity, or 
density of flow, and of nearly the same tension and storage capa- 
city as that commonly yielded by the usual mode of construction, 
and of charging and discharging a Faure accumulator with lead 
plates. 
The proces-es of maturing or ‘‘forming ” the coked platinum- 
plate, and of charging and discharging it, exactly resembles the 
usual processes with a lead one. At the same time, if leakage 
by local action is not entirely prevented, it must at least be re- 
duced to a minimum on a plate of platinum, and such a plate is 
not liable, like a lead one, to suffer gradual destruction by occa- 
sional accidental wants of watchful attention agzinst over- 
charging it. 
