‘ 
‘the attention of the graduates of the University of London. 
Sept. 25, 1873] 
NATURE 
433 
upon a surface of calm water, they are, in part, reflected accor- 
ding to the usual law, and a rainbow is then seen by reflection. 
But the absolute position of the bow changes with every change 
in the position of the observer’s eye ; ees the bow seen 
mirrored in the pool is ofthe reflection of that seen at the 
same time directly in the heavens. Suppose the shower to be 
fixed in space, then the drops which produce the bow seen 
directly, would not be those which produce the bow as seen by 
reflection. 
In the paragraph to which your correspondent “‘Z.X.Y.” has 
called attention, I meant to combat the notion, entertained 
by many, that the rainbow is reflected after the fashion of an 
ordinary floating cloud which emits light in all directions, and 
which, by the light thus emitted, paints its image in the water. 
A few additional words might have made my meaning clearer ; 
but as I was dealing at the time more with historic statement 
than with scientific exposition, I desired to be brief. I can 
hardly think, however, that your correspondent will be angry 
with me for giving him what must have been agreeable as well 
as successful occupation at the Falls of the Rhine. 
Royal Institution, Sept. 15 Joun TYNDALL 
Original Research at the Universities 
My attention has been arrested by the following sentence in 
the extract given by you from Prof. Frankland’s evidence 
before the Science Commission :—‘‘I believe that one cause 
(of the slow progress of original research in England) lies in the 
entire non-recognition of original research by any of our Uni- 
versities. Even the University of London, which has been fore- 
most in advancing instruction in experimental science, gives its 
highest degree in Science without requiring any proof that the 
candidate possesses the faculty of original research, or is com- 
petent to extend the boundaries of the science in which he gra- 
duates.” 
It may interest Dr. Frankland and those who take the 
same view as he does, to know that this subject has engaged 
At 
a meeting of the Annual Committee of Convocation in December 
last, it was moved by Prof. Guthrie— 
“ That every candidate for the degree of Doctor of Science shall 
be required to submit to his respective Examiners a written dis- 
sertation embodying some original research in one or more of 
the subjects of his intended examination ; and that such disser- 
tation be approved before the candidate be allowed to proceed 
to examination.” 
This motion I had the honour of seconding ; but the degree of 
acceptance which the principle involved in it met with from 
the Committee is seen by the sequel, as stated in the 
printed minutes, that it was “ rejected by a large majority.” 
The exact numbers, if my memory serves me rightly, 
were Ayes, 3; Noes, 16; among the Noes were two Doctors 
and one Bachelor of Science, and at least five Doctors of Medi- 
cine. The ‘* Annual Committee,” it may be stated, is a repre- 
sentative body elected annually by the graduates in Convocation, 
but has no legislative or administrative power, this resting en- 
tirely with the Senate. 
ALFRED W. BENNETT 
Endowment of Research 
WITH regard to the Endowment of Scientific Research, could 
“not this be well placed in the hands (as it now is, toa very 
limited extent) of a Committee of the British Association? the 
committee being authorised to supply funds for experimental 
purposes, and the members, say three or four in number, to-have 
a permanent salary for the time spent in the examination of 
claims from applicants. 
It might possibly be desirable that one or more of the com- 
mittee should retire every two or three years and not be eligible 
for re-election until after the lapse of three years ; and also, to 
prevent waste of time, that all applications for help should be 
presented only through one or more gentlemen of known scien- 
tific attainments, and not of necessity at the instigation of the 
person to whom the assistance was to be rendered. I believe 
that this would be a good practical arrangement as regards the 
poorer class, who are compelled to throw up valuable original 
researches to supply themselves and those depending on them 
with homes and food. 
The abuse of a trust of this kind would hardly be possible, as | 
the help would of necessity be given in those cases where a cer- 
tain amount of work had already been done under difficulties, 
and where the natural instinct for original research was of neces- 
sity strongly developed. The presentation of an annual sum for, 
say five years, renewable at the end of the time if necessary, 
would be a godsend to many a man who has allowed himself to 
starve for the benefit of posterity. 
THos, FLETCHER 
FERTILISATION OF FLOWERS BY INSECTS * 
III. 
On the co-existence of two forms of flowers in the same species or 
genus,—a more conspicuous one adapted to cross-fertilisation by 
znsects, and a less conspicuous one adapted to self-fertilisation. 
INCE Darwin, in his admirable work on Orchids, t had 
proved that the flowers of this family are endowed with 
an immense variety of comtrivances for cross-fertilisation 
by insects, it was almost generally admitted by botanists 
that cross-fertilisation is the rule throughout the whole 
vegetable kingdom. Darwin’s well-known aphorism, that 
“ Nature abhors perpetual self-fertilisation” was exagge- 
rated by his successors in this field of research, Hilde- 
brand in Germany and Delpino in Italy, who, in their 
various elaborate memoirs on the fertilisation of flowers, 
repeatedly expressed their strong belief that nature abhors 
self-fertilisation at all. In direct opposition to this 
opinion, Axell { propounded the doctrine that the develop- - 
ment of the fertilising arrangements in phanerogams has 
been always an advance, and still continues to advance, 
in one and the same direction, towards a perfection which 
affords more and more facilities for self-fertilisation. 
My own observations on the contrivances of our 
flowers and on the insects really visiting and fertilising 
them, have convinced me, that neither Hildebrand’s and 
Delpino’s, nor Axell’s opinion is a thoroughly adequate 
one, but that under certain conditions the facility for self- 
fertilisation is most advantageous to a plant, while, under 
other conditions, the inevitableness of cross-fertilisation 
by the visits of insects is the more advantageous, 
To all plants the flowers of which possess such a 
degree of attractiveness for insects that cross-fertilisation 
by these transporters of pollen is never wanting, the 
possibility of self-fertilisation is quite useless, and from this 
cause, not being subjected to the effects of natural selec- 
tion, may be lost, like any useless peculiarity, and in 
many instances, indeed, has been lost. On the contrary, 
to those plants the flowers of which possess so slight a 
degree of attractiveness for insects, that the transportation 
of the pollen to the stigma by insects is effected in but 
very few cases, the possibility of self-fertilisation is most 
advantageous, and indeed we find in most cases such plants 
well adapted for self-fertilisation. 
Among many facts which I could appeal to as proofs 
of my statements, there are, I believe, none more in- 
structive than those alluded to in the superscription of this 
article. 
In some species of our wild plants I have found on 
different plants two different forms of flowers, evidently 
showing the connectionabove stated between attractiveness 
for insects and adaptation for inter-crossing or for self- 
fertilisation. As nobody before, for aught I know, has 
observed this phenomenon, I will give some details of 
the most important instances hitherto observed. 
Lysimachia vulgaris 
Of this species specimens with more conspicuous 
flowers are found in sunny localities. The petals of this 
form are dark yellow with red at the base, on an average 
about 12 mm. long, and 6 mm, wide, opening widely and 
* Continued from p. 206. — ae 3 
+ “On the Various Contrivances by which British and Foreign Orchids 
are Fertilised by Insects.” (London, 1863.) 
4 In his work: ‘‘Om anordningarna for fanerogama vaxternas befrukt- 
ning.” (Stockholm, 1869.) 
