NA LORE 
[MarcH 31, 1904 
510 
Highway Construction in Wisconsin. By E. R. 
Buckley, State Geologist of Missouri. Pp. xvi+ 
339. (Published by the State at Madison, Wis., | 
1903.) 
Tuts book forms part of the Economic Series of works | 
published by the State of Wisconsin, and is an 
evidence of the trouble that is taken in the United 
States to furnish the officers having charge of the 
various departments with the fullest information as 
to their work that is available. 
It contains eight chapters, relating respectively to 
the classification of highways, and the agents that 
destroy pavements; materials used in improving high- 
ways; methods of constructing different kinds of pave- 
ments; drainage; pavements constructed in the larger 
cities; abrasion and cementation tests. 
In the introduction the writer points out that a pur- 
chaser or seller who is separated from a railway 
station by ten miles of good roads is actually nearer 
his market than the person who is separated by five 
miles of unimproved roads. Good roads mean heavier 
loads, more rapid transit, and a longer life for vehicles 
and horses. 
That such a work as that now under notice is 
urgently required in the State of Wisconsin may be 
inferred from a further statement made by the author, 
that a dog is able to draw a load to market in many 
European countries which a horse cannot draw in the 
United States, and that up to the present time high- 
ways in Wisconsin are simply narrow tracks connect- 
ing different parts of the country, the one idea of con- 
struction being to fill the gullies and level off the road- 
way with such material as might be closest at hand. 
There is some useful information contained in the 
book as to the tests carried out by the State for ascer- 
taining the relative wearing values of different kinds 
of stones used in road-making, from which a lesson 
might well be learnt by the county councils in this 
country as to the advantage to be gained by main- 
taining an establishment for supplying their road 
surveyors with trustworthy data of this character. 
There is one kind of pavement in use in some of the 
cities that might with advantage be used in this 
country, that is, blocks made of asphalt and laid in 
the same way as granite pavings. This pavement is 
stated to be non-slippery, while at the same time it is 
noiseless and non-absorbent. The cost is about the 
same as sheet asphalt. 
Practical Chemistry. Part ii. 
M.A., F.I.C., and T. H. Boardman, M.A. Pp. 
xilit+126. (London: Methuen and Co., 1904.) 
Price 1s. 6d. . 
Tuts book contains a well arranged series of experi- 
ments of a kind suitable for young students who have 
already spent a fair amount of time at practical 
chemistry. The physical properties of gases, the laws 
of chemical combination, sulphur and its compounds, 
some nitrogen compounds, and carbon and its simpler 
compounds, are among the chief subjects included in 
the volume. 
Marsh-Country Rambles. By Herbert W. Tompkins. 
Pp. xi+307. (London: Chatto and Windus, 1904.) 
Price 6s. 
Mr. Tompkins confines his rambles, with few excep- 
tions, to the marshlands east of the road which leads 
from Prittlewell to Maldon and Colchester, and south 
of the road from Colchester to St. Osyth. He does 
not pretend to offer the reader detailed descriptions of 
villages and towns, but rather to provide an interesting 
narrative in which history and legend are incidentally 
touched upon. With the exception of a frontispiece 
the book is not illustrated. 
NO. 1796, VOL. 69| 
By William French, | 
LETLERS 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 intended for this or any other part of NATURE. 
No notice is taken of anonymous communications.] 
The Occurrence of Thorium in Ceylon. 
Tur Government of Ceylon determined last year to carry 
out, with the cooperation of the scientific and technical 
department of the Imperial Institute, a systematic survey 
of the economic minerals of Ceylon. Mr. K. 
Coomaraswamy and Mr. H. G. Parsons were selected to 
conduct the survey in Ceylon, and to dispatch specimens 
of the minerals found to the Imperial Institute for chemical 
examination and commercial valuation. Among the speci- 
mens thus received were those of a mineral existing in 
small black cubical crystals found in the refuse from gem 
washings near Balangoda, in the Sabaragamuwa Province, 
which had been identified by Mr. Holland, a resident in 
Ceylon, as probably uraninite or pitchblende. The same 
mineral has been since observed by Mr. Coomaraswamy in 
a vein of pegmatite at Gampola, in the Central Province of 
Ceylon. 
The specific gravity of the mineral was found to be 9-32, 
and an analysis by Mr. G. S. Blake, of the scientific staff 
of the Imperial Institute, furnished the following results :— 
Per cent. 
Thorium oxide Tho, 76°22 
Cerium oxide ... ae: as CeO, \ 8-0 
Lanthanum and didymium oxide La,O3 Di,O3 J 4 
Zirconium oxide ee os ee LEOs trace 
Uranium oxide UO, 12°33 
Ferric oxide Fe,O5 0°35 
Lead oxide PbO 2°87 
Silica SiO, O12 
99°93 
The mineral is clearly not pitchblende, since the per- 
centage of oxide of uranium is only about 12 per cent., 
whilst the principal constituent is oxide of thorium (thoria), 
which is present to the extent of more than 75 per cent., an 
amount tar higher than that contained in any mineral 
hitherto examined. This mineral appears to be new, and 
I suggest for it the name of thorianite. Since it is radio- 
active, it will no doubt be found to be an important source 
of radium or radio-active earths, and will probably furnish 
helium, points which will be investigated as soon as more 
material has been obtained. 
A second part of the same specimen furnished the follow- 
ing results on analysis :— 
Per cent 
Thorium oxide ThO, 72°24 
Cerium oxide , ae CeO, vse OREO) 
Lanthanum and didymium oxide La,O3 Di,O, .-. 0°51 
Zirconium oxide Bee ZrO .. 3,68 
Uranium oxide UO, 11‘I9 
Ferric oxide Fe,O, 1°92 
Lead oxide PbO 2°25 
Silica a SiO, 1°34 
Insoluble residue O'4I 
99°93 
Specific gravity 8-98 
The two sets of analytical data prove that the material 
has essentially a uniform composition, the differences 
observed being apparently due to inclusions of zircon in 
the second portion analysed. 
In the meantime Sir William Crookes has received a 
specimen of the supposed pitchblende from Ceylon, and has 
found it to be radio-active to about the same extent as 
Cornish pitchblende. 
Sir William Crookes was good enough to give me a part 
of his specimen, which is being analysed. 
The second mineral examined was found by Mr. Holland 
in the same gem washings at Balangoda, and was identified 
as probably monazite. This mineral was pale brown, and 
when fractured exhibited a purple brown interior with a 
