202 
NATURE 
| Fuly 10, 1873 
to be determinable ; but in a future number of this journal I 
hope to be able accurately to name both the supposed milker 
and the supposed milk-cow. 
Lippstadt HERMANN MULLER 
Free-Standing Dolmens 
Mr. LUKISs, in a paper recently read before the Society of 
Antiquaries, nominally ‘On certain Erroneous Views respect- 
ing the Construction of French Chambered Barrows,” but really 
a method of criticising severely Mr. Fergusson’s work on the 
**Rude Stone Monuments,” states that it is an ‘‘error” to 
suppose that the Dolmens of that country were ever free-stand- 
ing; in other words, he lays down the ‘‘rule,” ‘‘ there were no 
free-standing dolmens in France.” The announcement that, 
with regard to monuments of whose fashioners we know abso- 
lutely nothing, a universal negative of this kind can be safely 
laid down as a law, would be startling, did it not come from one 
who is backed by such extensive inductive evidence as is Mr. 
Lukis. His ‘‘rule” was ‘‘ established by the extreme rarity of 
the instances.” This being the case, he calls those ‘‘in error” 
who would, from these instances, form a small class, or species 
of dolmen. As, in an essay on the Cornish sepulchral monu- 
ments, which you recently most kindly reviewed at length, Lam 
committed to this latter view—one, by the way, which I had 
struck out for myself before the appearance of the “‘ Rude Stone 
Monuments,” —will you kindly permit me to call yourattention to 
one structure which I have ventured to place, and shall still ven- 
ture to place, in the discarded class? I do so asa protest against 
the dictum of Mr. Lukis being extended to our British examples, 
before a careful scrutiny has been made of every monument of 
the kind from one corner of our islands to the other. On this 
single instance, such as it is, it must be clearly understood that 
T build no theory ; it will be for others to judge whether it does 
not afford some evidence of the difference in construction and 
use of the dolmen or table-stone proper, and the kist-vaen crom- 
lech ; one thing only I will add, that, limited as my experience 
is to the monuments of Britain, I shall not be exposed to the 
temptation of explaining away any observed fact in order to re- 
concile a doubtful comparison, Without feeling that I am 
guilty of ‘‘dabbling in archzeology,” or of setting forth ‘‘any 
dogmatic expositions of hypotheses” (!!), or of ‘establishing 
my proposition from second-hand information,” or in short of 
being the victim of any very ‘‘ erroneous view ” (all which faults 
Mr. Lukis finds in those who differ from him), I consider that 
the following facts justify my statement that the monument I am 
about to describe always was, as it is now, a free-standing 
dolmen. 
At Lanyon, in the parish of Madron, Cornwall, stands a 
tripod dolmen, or cromlech, consisting of three slim pillars of 
unhewn granite supporting on their summits a horizontal stone 
over 40 ft. in circumference and averaging 20 in. thick. In 1815 
it fell ; but previous to its fall a man on horseback could sit 
upright underneath the cap-stone. In 1824 it was again set up ; 
but two drawings had been made of it in its pristine condition, 
one by Canon Rogers in 1797, and the other by no less accurate 
a draughtsman, half a century before, namely, by my ancestor, 
Dr. Borlase. Both these drawings agree in representing the 
extreme slimness of the pillars; their distance apart ; and the 
great height of the monument; features which render it not 
unlike a gigantic three-legged milking stool. Then, as now, 
there was no mound about it, as there is in the case of 
each and all of the kist-vaen cromlechs. It stood on 
a low bank of earth, and the area had been often dis- 
turbed by treasure seekers. No houses are near it 
which could have received the stones of a denuded mound. 
Added to this, it is difficult to see how a kist-vaen, or sep/um 
of any kind, could have been formed beneath the cap-stone. 
Had a wall of sail stones been built up from pillar to pillar the 
weight of the superincumbent mound must have forced them in- 
wards, a catastrophe which the ‘‘dolmen-builders” were always 
most careful to avoid. Secondly, had /avge stones placed on 
edge formed the walls of the kist, how is it they are a// removed, 
while every other cromlech in the district retains them? But, 
laying aside this evidence, my strongest proof is yet to come. 
The {interment in this instance was vot in the hist at all. A 
grave had received the body six feet under the natural surface of 
the surrounding soil, and within the area described by the struc- 
ture. This being the case, of what use could an enclosed kist 
have been ; or why should the cenotaph be covered in at all? 
Add to this again, that on the southern side of the structure, and 
so near it that a mound over the monument must inevitably have - 
covered it up, stands a little circular ring cairn of the ordinary 
type, in the centre of which I found the remains of an inner 
ring, which, though now rifled, had doubtless contained an in- 
terment. Must I then explain away in deference to superior ex- 
perience or received opinion each and ail of the above facts, in 
order to reconcile this monument with those which seem to be 
totally different structures, viz., the kist-vaens?* Should I not 
by so doing b2 sacrificing a fact to amhypothesis, and is not that 
hypothesis of such a nature that even a single instance well es- 
tablished must shake it to its foundation? Should I not incur a - 
charge of erroneousness equal to, if not greater, than that which 
Mr. Lukis brings to bear on all who differ from him? 
No one can wish more than I do to see errors expunged, and 
the truth in these matters arrived at; but I must confess that [ 
cannot see how this will be brought about by confronting one 
hypothesis with another equally dogmatic, and more universally 
inclusive, WIix.1AM C. BorLASE 
Castle Horneck, near Penzance 
Fertilisation of the Pansy 
I am glad to be able to confirm, to-some extent, from obser- 
vation, Mr. Bennett’s theory of the fertilisation of the Pansy, 
given in NATURE, vol, viii, p. 49. I watched a considerable 
number of specimens of Viola tricolor on a grassy hill-top 
where the smaller insects were very numerous and busy, and 
twice saw them entered by a minute fly. In the first case the 
insect was dusty with pollen when it arrived. It settled on the 
lower petal and walked up one of the black lines to the gap in — 
the ring of anthers, through which it entered with some diffi- 
culty—leaving some of the foreign pollen on the stigma as it 
passed. When it came out it had still more pollen on it than 
when it went in, and again in passing the stigma it left some on 
it. It paused a moment on the lower petal to clean itself, and 
left a little ball of pollen on the hairs on one side of the stigma. 
In the second case, the insect alighted first on one of the upper 
unmasked petals, turned round and round as though seeking the 
guiding lines, and flew off to the lower petal, where, without 
hesitation, it followed the guiding lines as the other had done. 
After it had passed the stigma there was no pollen visible on its 
surface ; but after it had come out, almost the whole of the 
lower half was covered. In each case the passage through the 
ring of anthers seemed rather a struggle. There were many bees 
about, but I did not see any of them visit the Viol, although 
they were almost the only flower near. A. T. MYERs 
Penrith, June 30 
European Weeds and Insects in America 
A CANADIAN friend writes to me :—‘‘I have heard or seen 
it mentioned as a fact that European weeds and insects intro- 
duced into America flourish for a while, but after fifty or sixty 
years gradually disappear: for instance, that the Hessian fly 
(so called from having been brought over by the Hessian troops 
in their hay in the war of independence) has died out or ceased 
to give trouble, though at one time it totally destroyed the wheat 
crops of New England. I do not know how far the facts haye 
been tested, or how far they are owing to improved agriculture.” 
This statement, if true, is obviously of great importance, 
Can any of your correspondents confirm or disprove it ? 
JOsEPH JOHN Murpuy 
Old Forge, Dunmurry, July 4 
CHLOROPHYLL COLOURING-MATTERS t+ 
ee would be impossible for me not to look upon 
the appearance of such a work as the one recently 
published by Dr. Gregor Kraus with much satisfac- 
tion, since the chief object of the author is to call the 
attention of his countrymen to the value of the spectrum- 
microscope in studying the colouring-matters of plants. 
He commences with a description of the instrument, and 
says that, though originally designed for the examination 
of microscopical objects, it is not only as useful as any. 
* The only other tripod dolmen in Cornwall, viz., that at Caerwynen, is 
also a free standing one (within the memory of man, at least), whereas the 
kist-vaens are one and adi partially covered by their envelope. 
+ ‘On the Chlorophyll Colouring-Matters.” (‘Zur Kenntniss der 
Chlorophyllfarbstoffe und ihrer Verwandten”). By Dr, Gregor Kraus. 
(Stuttgart, 1872.) , 
