448 
NATURE 
| DECEMBER 18, 1913 
the grasp of the scientific tyro, and a well-informed 
chemist would probably find little that was new 
to him. Nevertheless it is not without a certain 
fascination, if only by the mere perusal of a record 
which exhibits in a striking manner the wonderful 
fertility of the science and its extraordinary growth 
in recent years. Moreover, it is well written, well 
printed on good paper, and handsomely bound. 
Anyone who succeeds in assimilating a fraction 
of the contents of the other fifty-nine volumes, in 
addition to this, may indeed claim to have reached 
a condition of modern culture of unexampled 
thoroughness. J Bae. 
GAS, LIGHT AND AIR. 
(1) Gas Testing and Air Measurement. By C. 
Chandley. Pp. vii+77. (London: Methuen and 
Co., Ltd., n.d.) Price 1s. 6d, 
(2) Light, Radiation, and Illumination.  Trans- 
lated from the German of Paul Hégner by 
Justus Eck. Pp. xii+88. (London: The 
Electrician Printing and Publishing Co., Ltd., 
n.d.) Price 6s. net. 
(1) HE title of the first of these books is 
somewhat misleading. In these days 
of high-pressure gas and the use of burners in 
which the adjustment of the induced air is of the 
first importance, it is very natural to suppose that 
a work entitled ‘‘Gas Testing and Air Measure- 
ment ’’ has something to do with gas burners. 
This is not the case. By gas is meant fire-damp 
in mines, and the air measurement refers to the 
ordinary practice in mines of measuring the venti- 
lating currents. 
The author deals with the indications of the 
safety lamp as an indicator of the proportion of 
fire-damp if this is not outside the limits of 2 and 
5 or 6 per cent., and of the effect of quantities 
above the explosive limit in putting out the flame. 
He does not refer to any of the devices that have 
been used for showing smaller quantities, as, for 
instance, Prof. Clowes’s hydrogen lamp or 
Liveing’s fire-damp indicator. The book is in- 
tended primarily for candidates for certificates 
under section 15 of the Coal Mines Act, 1911. It 
should serve this purpose well, as the discussion 
of the all-important cap of the flame of the safety 
lamp is very clear; some attention is given to the 
legal requirements and official regulations relating 
to coal mines, and the methods used for measuring 
ventilating currents are very fully explained. 
(2) ‘‘ Light, Radiation, and Illumination ’’ is 
an admirable exposition of the science which forms 
the basis of the practice of the illuminating” en- 
gineer. It is the object of the members of this 
recently organised profession to apply light so as 
to obtain economical and satisfactory illumination, 
NO. 2303, VOL. 92] 
and not merely to place so many hundred candle- 
power of illuminating means ina room or a street. 
The scheme of the book is not unlike that of 
Euclid, but using the methods of trigonometry 
and the calculus and geometrical illustrations of a 
series of propositions following in logical sequence 
the demonstrations are as clear as any in Euclid, 
but the time and space required are vastly less 
than that which would be necessary with a purely 
geometrical method. 
Beginning with a flat element of surface of a 
given luminous intensity, the author shows that 
the light radiated in different directions in space 
is proportional to the chords of a sphere to whiclr 
the flat surface is tangent at the element. Then 
gradually sources of other geometrical forms are 
considered, and such real sources of light as fila- 
ments and arc light carbons. The illumination of 
surfaces and spaces, the effect of light-coloured 
walls, the curves of illumination from different 
sources, the uniformity of illumination with many 
lamps, and many other branches of the subject 
are treated fully and convincingly, and numerous 
tables for facilitating calculations in real cases are 
found as they are required. 
While the forms of the illumination curves given 
by incandescent electric lamps and three kinds of 
are lamps receive their full share of attention, no 
reference whatever is made to gas lighting. Now 
that the most beautifully lighted streets in London 
-——Victoria Street, Pall Mall, and other streets in 
the West End, covering some miles—are lighted 
by high-pressure incandescent gas, it seems rather 
an omission not to have any statement even of the 
nature of the illumination curve of this type of 
burner. While the publishers may persuade 
themselves that electric illumination now is, after 
daylight, the only kind that matters, this is not 
the fact, and the author might with advantage 
have given the illumination curve of one type of 
high-pressure gas burner. In spite, however, of 
this omission, the book is a splendid example of 
science applied to an art which has been too long 
neglected. 
OUR BOOKSHELF. = 
The Place of Climatology in Medicine: being the 
Samuel Hyde Memorial Lectures, 1913. By Dr. 
W. Gordon. Pp. v+62. (London: H. K. 
Lewis, 1913.) Price 3s. 6d. net. 
Ar a time when the broad features of the climate 
of civilised countries are well established through 
long series of exact observations, it is well to be 
reminded that an accurate knowledge of the local 
variations, especially of wind and rainfall, are of 
vital importance in medical climatology. We have 
yet to produce properly contoured large-scale 
maps of climate, even for well-populated districts, 
