242 
NATURE 
[OcTOBER 23, 1913 
The paper contains a large collection of data 
especially important as all relating to the same area 
and extending over a long period, but a marked want 
of care is shown both in the handling of the records 
and in the conclusions drawn from them. Numerous 
errors left uncorrected in the tables are very confusing 
though not, it would seem, seriously affecting the 
main results. Greater importance attaches to conclu- 
sions formed often quite out of proportion to the 
evidence available. As regards the question of noc- 
turnal migration to the surface, while the records 
show the strongest evidence of a surface maximum 
during the night hours, they are far too incomplete 
to be relied on as indicating any definite period of 
optimum conditions. The maximum obtained for 
Calanus finmarchicus, for example, between 10 and 
I2 p.m., rests on the slender evidence of a single 
haul of 2-8 hours in duration, in which between three 
and four thousand specimens occurred. If this were 
indeed an optimum period, a higher average than 
fifty-eight specimens per hour might be expected be- 
tween midnight and 2 a.m. The occurrence of a 
species in exceptionally large numbers suggests the 
presence of exceptional conditions, it may be, a com- 
bination of several factors at the time, to account for 
it. In estimating averages such a haul may, if un- 
supported by other evidence, give results that are quite 
misleading, and where it is used, as in the present 
case, for time-frequency alone, it is unsafe to place 
narrow limits to the period in which it happens to 
fall. In the two-hour period preceding this, viz. 
8-Io p.m., an average of 973 specimens per hour is 
obtained from eight hauls made during that time. 
Had no other data been available than the four hauls 
covering this period in Table 2, the average given 
would be no more than nineteen specimens per hour 
in place of the 973. The example,serves to emphasise 
the need of repeated observations before any safe 
estimate of such averages can be formed, or any 
deductions made from the latter. 
The same remarks are applicable to the averages 
for Eucalanus and Metridia especially. For the 
former three maxima are shown, for the afternoon, 
evening, and morning severally, and the suggestion 
is even put forward that these are probably of normal 
occurrence, and should be considered so. The maxi- 
mum for Metridia, placed at 1o-12 p.m., rests, like 
that of Calanus, on the unsafe basis of a single haul 
of 31,900 specimens, the same haul as that from 
which the maximum for Calanus was obtained. The 
second highest aggregate for this species, namely 3401 
specimens, was obtained from three hauls made be- 
tween midnight and 2 a.m., and is apparently likewise 
dependant almost entirely on one haul of 3200 
specimens, leaving an average of roo specimens for 
the other two. In the case of Labidocera trispinosa 
the disproportion is greater still. Here the maximum, 
falling between 6 and 8 p.m., shows an aggregate of 
2630 specimens obtained during this period in five 
successful hauls out of thirty, one haul containing 
2425. The second highest aggregate, falling between 
4 and 6 a.m., with a total of 527 specimens obtained 
in seven hauls, includes one haul with 500 specimens. 
It cannot be lost sight of that all of these higher 
figures occur between the late evening and early 
morning hours, and, as a matter of general 
observation, the night preponderance of Copepod 
plankton near the surface will not perhaps be 
questioned by many. But data such as these are 
manifestly too incomplete alone to bear any inter- 
pretation more restricted than this, and though re- 
garded by the author as implying different optimum 
periods characterising the different species, seem rather 
to express collectively particular instances of more or 
less abundant occurrence, in which any one or other 
NO. 2295, VOL. 92] 
of the species considered might equally well have 
been encountered on another occasion. It is indeed 
difficult to understand how, reasoning on such frail 
evidence, the discussion is carried even to the point 
of recognising in these different maxima obtained 
hidden characters distinguishing the species which 
are supplementary to those of structural features, such 
as to indicate, it may be, with more extended know- 
ledge the apparent rather than real nature of the 
latter. 
In estimating the hourly averages for the surface 
hauls the time occupied is made to include, rightly 
it would seem, that of hauls from which a species was 
absent. Thus is obtained the average number of 
animals occurring per hour of hauling. In calculat- 
ing the depths for the day plurima, as shown by the 
self-closing nets, the averages based on the number 
of animals per fathom passed through are not treated 
in the same manner, but merely express the depth 
of the layer of water as a fixed quantity regardless 
of the number of hauls made through it. Thus, for 
C. finmarchicus, the region of the day maximum 
shown between 50 and 77 fathoms is estimated by all 
the animals in all the hauls (seventeen) made through 
that section of water being treated as though occur- 
ring in one haul through 25 fathoms. The average 
found at this depth, namely, 15°7 per fathom, therefore 
denotes no more than the distribution over the layer 
concerned of an aggregate of animals captured be- 
tween 50 and 75 fathoms, and cannot be considered as 
on the same plane with that found between 75 and 
100 fathoms, where six hauls made through a similar 
depth of water show an average of 57 animals per 
fathom. If the repetition of hauls through a given 
column of water be not given a true value, the 
averages are incomparable with one another, and im- 
portant evidence afforded will be lost in the results 
obtained. 
Considerable distortion of the latter averages is 
liable to have arisen through no allowance having 
been made for differences in the size of the nets 
used, amounting to as much as one-half the mouth 
opening. The impression that such allowances are 
of no practical value, if intended to be understood 
literally, might have been removed had the author 
tested the different-sized nets against one another. 
LL. Rags 
THE BRITISH ASSOCIATION AT 
BIRMINGHAM. 
SECTION K. 
BOTANY. 
OpeninG Appress By Miss ETHEL SARGANT, PRESIDENT 
OF THE SECTION. 
WE were welcomed to Birmingham last night, and 
now—made free of the city—we assemble this morn- 
ing to justify our position as its guests. But before 
entering on the work of the section, your president is 
authorised, and even required by custom, to glance 
at the events of the past year in the botanical world. 
My predecessor in this chair had a great loss to 
record in the death of Sir Joseph Hooker, the doyen 
of British botanists, and a familiar figure at so many 
meetings of this Association, where we were proud to 
feel that he belonged to our section. This year we 
have no peculiar grief, but we join with the whole 
Association in lamenting the death of Lord Avebury. 
We have some right to offer a special tribute to his 
memory, since several of his published works were 
on botanical subjects. His book on the “‘ Fertilisation - 
of Flowers’’ in the ‘‘ Nature Series’’ opened a new 
world to many non-botanical readers, and there are 
