Retrospective Criticism. 457 
be unquestionable. As for his electrical experiments made on spiders and 
their lines, I again affirm that I have repeated the greater part of them, 
with all the exactness of which they are susceptible, without having suc- 
ceeded in establishing their validity in a single instance. 
With a degree of inconsistency almost unparalleled, Mr, Murray ex- 
presses his contempt for authorities at the very time he is appealing to 
others in support of his own statements. Now, surely the observations of 
a Humboldt are as deserving of confidence as the attestations of Mr. Mur- 
ray’s anonymous friends can be. 
"That I am not the only individual whose attempts to confirm the accuracy 
of Mr. Murray’s experiments on spiders have proved ineffectual, will be seen 
from the following passage, transcribed from a work entitled Insect Architec- 
ture, published under the superintendence of the Society for the Diffusion of 
Useful Knowledge. The author, after giving an abstract of Mr. Murray’s 
investigations (part ii. p. 345-6.), adds, “ Such is the chief evidence in sup- 
port of the electrical theory ; but, though we have tried these experiments, we 
have not succeeded in verifying any one of them.” This extract, certainly, 
is not adapted to remove Mr. Mur ray’s prejudice against authorities; I am 
persuaded, however, that it will not be deemed unimportant by impartial 
enquirers. 
I proceed to notice Mr. Murray’s remarks upon the “ dark brown glossy 
gossamer spider,’ which, with his usual want of precision, he terms a 
variety. After asserting the correctness of his former observations on the 
speedy dissolution of this species in a state of confinement, he recommends 
repetition of the experiment, but is evidently reluctant that I should in- 
Featinete the matter further. Thus Mr. Murray not only declines to try 
my experiments, but would gladly preclude me from examining his. Could 
this have been anticipated from one whose professed object is the promo- 
tion of truth? Any comment would be superfluous. The results of my 
researches on this subject may be found in my letter of the 18th of July, 
1829 (Vol. II. p.397-8.), and subsequent experiments confirm their accu- 
racy. 
Mortified that he cannot controvert the evidence advanced in support of 
my doctrines, Mr. Murray is mean enough to intimate that I maintain opi- 
nions which I know to be false. I ean make every suitable allowance for 
the irritation of a vanquished adversary, but so glaring a delinquency as this 
is quite inexcusable. 
In retiring from this needlessly protracted contest, my antagonist conde- 
seends to assure me, that if I can satisfactorily confute the facts and phe- 
nomena recorded in his Experimental Researches in Natural History, he 
shall give me credit for more wit than he supposed I possessed. To correct 
the numerous errors contained in that publication would be a practicable 
though laborious undertaking: but who, beside Mr. Murr ray, ever thought 
of confuting facts and phenomena? Tf his good opinion is to be obtained 
on this condition only, there remains no alternative for me but to endeavour 
to console myself without it. Iam, Sir, &e.—John Blackwall. Crump- 
sall Hall, March 8.1830. 
The Ascent of the Spider. — Notwithstanding what Mr. Rennie says, in 
his very delightful book on insect architecture, Bowman and Murray are 
certainly right. It is by electric influence that they ascend. It was on 
the apex of the gnomon of my sundial here that I saw these gentlemen 
separately make their experiments. They wish me, as does D , to strike 
a blow in your Magazine; but I abhor controversy, and this spider one 
seems to have banished courtesy. —J. F. M. May 30. 1830. 
Flight of Spiders. —1 feel indebted to Mr. Thompson, of Hull, for the 
record of this phenomenon. (p. 47.) IT notice it here as a singular coinci- 
dence with what I had myself observed on the 28th of July last, in a hay- 
field near Hull, and published in my Treatise on Atmospherical Electricity UP 
Vou. III. — No. 15. H OH 
