Fuly 16, 1885] 
or 4°560 candles, gives the gain in light per cubic foot of 
gas due to the regenerative arrangement, the gas burning 
within a highly-heated atmosphere. pee cre, 
a | c 
E =| 4B!) an 
@ |ef| 3 | s&|3s 
ie} = ae sal es 
Sill eS libcaie | caren are 
Dat Particulars of a Sis a Pa | SE 
mex Burners. Ze & |3e} gb 
2 RC) Mee lbiseoellt eae 
n O56 BP icg el vo 
— Os it. Wf oF g 
a 3 1S) 4H | 9 
& ees) lig 
May 6, 1885.) Gas jets taken ‘out of | Ten- | 
Jie Tao Aas > + + |tenths| 20% | 57°5 | 2°875| «+ 
9 Same jets raised 18 inches | 
to reflect light on | 
mltneeo in Geo Be 20'0 | 550 | 2°750 | 
> Same jets burning in cold 
Dilampe esp et: An 20°5 | 62°5 | 3°048 | 3°180 
= Same jets burning in hot 
Lannie me cvekeshS. = ces =5 15°5 |115°0 77420 | 7°740 
Of course light may be diffused or transmitted in- 
directly by other means than those described, though not 
perhaps in a more simple or economical way. The elec- 
tric light has been to a certain extent already treated in a 
similar way by suspending arc lights at great altitudes, 
and by means of reflectors concentrating the light down 
upon certain areas. The intention has been, by this 
means, to illuminate whole towns or districts of towns from 
single sources of light. This can, in the author’s opinion, 
be done if the concentration of the light is effected in a 
different way from what has been hitherto attempted— 
viz., by the employment of very much larger reflectors. In 
this way the loss of light sideways and the deep shadows 
that have been produced will be avoided. It matters very 
little at what height the light is placed, the chief question 
being what area has to be illuminated ; and then the form 
of reflector suitable for the purpose can be easily deter- 
mined upon. 
In conclusion, it must be remembered that illumination 
from above downwards is in nearly all cases the preferable 
mode of distributing light, as Nature herself proves in 
having one light only, the sky being the diffusing agent 
by which the most perfect distribution of light is effected. 
Nature possesses, indeed, a gigantic reflector in the at- 
mosphere and clouds ; and the author has endeavoured 
to imitate Nature’s reflector in a way suitable to our 
imperfect means and conditions, and to the circumstances 
of each individual case. 
2) THE VOVAGE OF THE “CHALLENGER.”? 
ie 
Tse plan adopted in the narrative of the cruise gives 
the reader a good idea of the course of the voyage, 
the nature of the researches carried on, and the manner 
in which these researches have been followed up by the 
more detailed studies of the experts into whose hands the 
collections were afterwards placed. But it is necessarily 
desultory. We are led from station to station, from 
chemical to biological work, from physics to ethnology, from 
deep-sea temperatures to the anatomy of sea-slugs, with 
a rapidity and suddenness that are a little bewildering. 
Still, the general impression of the far-reaching aims of 
the expedition, of the skill and completeness with which 
the work was done, and of the enormous mass of new 
material obtained, is no doubt deepened by the difficulty 
or impossibility which the narrators have obviously ex- 
perienced in giving within the brief compass of their 
chapters anything like a comprehensive digest of what the 
Challenger voyage accomplished in regard to the problems 
t This shows a loss of 4°35 per cent. owing to absorption by mirror. 
* “Report on the Scientific Results of the Voyage of H.M.S. Challenger 
during the years 1873-76.” Prepared under the direction of the late Sir 
(e Wyville Thomson, and now of John Murray. ‘‘ Narrative,” vol. I., 1885. 
Continued from p. 207. 
NATURE 
249 
of the great deep. The reader must resign himself to be 
carried along as the naturalists of the expedition them- 
selves were, and to listen to their story of what they saw 
and found. 
‘In our notice of last week we left the Challenger at the 
Cape of Good Hope. From that station she strikes out 
boldly into the Southern Ocean, giving us glimpses of the 
Prince Edward and Marion Islands, with their proofs of 
recent volcanic action, the Crozet Islands and Kerguelen. 
In this part of the voyage the trawlings are extraordin- 
fi 
8 
e 
avionon 
Se 
a 
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SLM Mahinoy 
wld 
LJ 
aD 
9) / We 
Wes WE 
i= 
= 
Sao BN a 
Fic. 4.—MZetacrinus Wyvitlit, P. H. Carpenter. 
arily rich, between one and two hundred animals coming 
up at each haul, representing nearly all the marine groups, 
and, with few exceptions, belonging to genera and species 
discovered now for the first time. Among the more in- 
teresting forms of life are various crinoids, the mention of 
which leads to a summary from Dr. P. A. Carpenter and 
Prof. L. von Graff of their Reports upon the additions to our 
knowledge of the recent crinoids made by the expedition 
Fig. 4). The figures of the living Pestacrinus remind the 
