NovVEMBER I, 1906] 
IVAL OTE, 15 
Tue second part, dealing with labour, of the General A paper by M. Edouard Collignon on the solution of 
Report on Mines and Quarries, has been issued by the 
Home Office as a parliamentary paper (Cd. 3179, price 
rod.). It shows that the total number of persons employed 
at British mines and quarries in 1905 was 982,343, of 
whom 887,524 were employed at mines and 94,519 at 
quarries. During the year, 1103 separate fatal accidents 
occurred at mines and quarries, causing the loss of 1304 
lives. Compared with the previous year, there is a de- 
crease of fifty-five in the number of fatal accidents, and 
an increase of 102 in the number of lives lost. The general 
death-rate from accidents at mines 1-358 per 1000 
persons employed. 
per cent. were caused by falls of ground. Five fatal 
accidents were caused by the use of electricity undergrouna. 
A very unusual accident is reported at Llanhilleth Colliery, 
where one man was killed and six men injured by the 
sudden blast of air caused by a fall from the side of a 
cavity. Some interesting statistics are given showing that 
gunpowder constituted more than 67 per cent. of the total 
weight of explosives used in collieries. About 30 per cent. 
of the weight used consisted of permitted explosives, those 
most largely used being bobbinite, saxonite, ammonite, 
roburite, and westfalite. Other statistics show that there 
were 295 collieries where coal-cutting machines were at 
work, the total number of machines being 946. The total 
quantity of coal obtained by the aid of these machines 
in 1905 was 8,102,197 tons. 
was 
We have received from the director of the Geological 
Commission, Cape Town, South Africa, the first separately 
issued sheet of the geological map of Cape Colony. The 
geology is by the director, Mr. A. W. Rogers, Mr. E. H. L. 
Schwartz, and Mr. A. L. Du Toit. The colour printing is 
clear, and there is not too much detail. The size of the 
imprint is 213 inches by 27 inches; the scale is 1 inch= 
1600 Cape roods, which is equivalent to about 3-7 miles 
to the inch. The commission is to be congratulated upon 
the production of an excellent map. 
Part i., vol. xxxiv., of the Records of the Geological 
Survey of India contains two reports upon occurrences of 
coal, one in the foothills of Bhutan, by G. E. Pilgrim, 
the other in the Kotli Tehsil of the Jammu State (Dandli 
coalfield), by C. M. P. Wright. Mr. Pilgrim contributes 
also some notes on the geology of Bhutan; Dr. Diener 
supplies notes on some fossils from the Halorites limestone 
of Bambanag Cliff, in which he describes a new genus, 
Martolites, near to Celtités of Mojsisovics, and a new 
species of Halorites, H. trotteri. He also describes the 
Upper Triassic fauna of Pishin. In the appendix, analyses 
are given of three samples of muds from the Travancore 
coast. 
Tue Rendiconto of the Bologna Academy is sometimes 
rather late in appearance, but the three last numbers 
(1902-5) contain one or two papers of more than passing 
interest. Prof. Guido Tizzoni, in the name of Dr. 
Bongiovanni, read a note on the influence of radium on 
the virus of rabies. It was shown that radium rays rapidly 
destroyed the virus, both when contained in tubes and 
when applied to animals within an hour or so of their 
infection, and methods were found by which animals 
already suffering could be cured with certain results. The 
previous number (vol. viii.) contains an account of the 
botanical results of the two scientific expeditions to Monte- 
negro organised by the Italian Government in 1902 and 
1903. 
NO. 1931, VOL. 75] 
Of the fatal accidents at mines, 44-0 | 
the cubic equation is published in abstract in the Proceed- 
ings of the Edinburgh Mathematical Society, xxiv. (1906). 
It is based on the property that every cubic can be reduced 
to one of the three forms x*=constant or x*+x=constant. 
By tabulating the values of x°+x and x*—~x for different 
values of x, the roots may be found in the same way that 
antilogarithms from a table of 
The properties of the roots are discussed in connection 
with the graphs of x*+x, and it will be noticed without 
going further into the details of the paper that the turning 
points of the curves determine very simply the conditions 
for three or one real roots. ‘he 
far a method is applicable to curves of higher 
degree. 
are taken logarithms. 
author examines how 
similar 
We have often directed attention to the excellent series 
of monthly volumes entitled the Practical Photographer, 
edited by the Rev. F. C. Lambert, and published by 
Messrs. Hodder and Stoughton. It was found that the 
size of page was rather too small to show off effectively 
the fine reproductions from well-known photographs which 
were a distinct feature of the series. In April last the 
size of page was doubled, and since that date we have 
received the monthly issues, which indicate the wise 
policy of such a change. The present series is now termed 
the Practical and Pictorial Photographer, and is issued as 
a library series, the price being the same as the previous 
volumes, namely, one shilling. The October number is 
full of interesting matter, and is illustrated by seventeen 
reproductions. 
From Messrs. Newton and Co. we have received a 
simple convex lens of 2-5 inches diameter, having a focal 
length of about 6 feet. On a small portion of the periphery 
of the lens is firmly sealed a metal base carrying a small 
screw, which enables the lens to be easily fixed to the 
end of a walking-stick or umbrella. The lens and attach- 
ment are enclosed in a neat leather case, which can be 
comfortably carried in the waistcoat pocket. This ** uni- 
lens,” which has recently been patented by Major Baden- 
Powell, serves the purpose of a low-power pair of 
opera-glasses without the trouble of carrying them. The 
use of such a lens in this manner is not new, but the pre- 
sent form of mounting will make it of more general service 
than hitherto. Those who possess approximately normal 
eyesight would find great comfort in having ready at hand 
such an easy means of magnifying distant objects. When 
placed on the end of a stick, and the latter held out at 
arm’s length, the object observed is seen at the greatest 
magnification, and even at less distances the object is 
always in focus, but not so much enlarged. The simplicity 
and portability of this ‘‘ unilens’’ should find favour with 
many who are in search of a pocket telescope. 
Tue first part, comprising no less than 1437 titles, of 
a valuable catalogue of important works, chiefly old and 
rare, on mathematics, astronomy, physics, chemistry, and 
kindred subjects, has just been issued by Messrs. H. 
Sotheran and Co. This ‘‘ Bibliotheca Chemico-mathe- 
matica ’’ will be completed in three or four parts, which 
will be issued at intervals of a few months each. The 
part just received has on the first page works by Ernst 
Abbe, Abel, and Abercromby, and the last titles are of 
works by Galileo. Among numerous other volumes ard 
memoirs included in the catalogue are a copy of the very 
rare first edition of the great work of Copernicus, ** De 
Revolutionibus Orbium Ccelestium ”’ (1543), which com- 
menced a new epoch in the history of astronomy ; the first 
