540 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[December 30, 1871. 
cough of infancy; here is an undoubted combination of all 
the constituents of balsam of tolu; and it is hard to under¬ 
stand on the above quoted theory, how any good can result 
from its use, unless we adopt the motto, “ Similia similibus.” 
(See also United States Pharmacopoeia.) 
Again, aged people (some who have even reached their 
second childhood) believe very much in the efficacy of Friar’s 
balsam, which, in addition to balsam of tolu, also contains 
benzoin and storax, both rich in the same principles. 
It does not seem possible that a clear syrup could be made 
if resinous and insoluble matters are suspended in it; what 
we prepare is uniformly bright and limpid. The matter may 
seem in itself trifling, but it is scarcely worth while adding 
to the time required for making a preparation which occupies 
quite enough of that valuable article, let it be done ever so 
expeditiously. 
R. Goodwin Mumbray. 
Richmond, December 18 th, 1871. 
Professor Tyndall’s Theory oe the Blue Colour 
of me Sky. 
Sir,—In answer to your correspondent Dr. Barnsley, of 
Barra Mansa, Rio de Janeiro, I would say that he appears 
to have allowed his ideas to be more or less confused by failing 
sufficiently to discriminate between the various modes of the 
conveyance of light known as “reflected,” “transmitted” and 
“ scattered ,? light, of which I am sure he will require no ex¬ 
planation at my hands. 
Replying to his first question,—no sunbeam, under spectral 
analysis, has been found without the blue waves. In looking 
directly at the sun the impression of colour is yellow or red¬ 
dish-yellow. The blue is also there; but so weakened in in¬ 
tensity as to be almost entirely overpowered in our percep¬ 
tion by the other constituents of the solar rays. 
In answer to the second question,—Dr. Barnsley takes the 
term “stopped” in a sense different to that which was in¬ 
tended by me. What I meant was, that the blue waves, on 
coming in contact with the particles, are not only stopped, 
but immediately scattered in all directions and reach our 
retinae, therefore, at all angles, producing a blue impression. 
Replying to Dr. Barnsley’s third question,—I must refer 
him to my answer to his first two questions, depending as it 
does on the meaning I intended to convey by the word 
“ stopped.” 
Dr. Barnsley’s remark, “that on the highest mountains the 
sky is of an inky hue,” is borne out by several authorities, 
among them Mr. T. Gf. Bonney, who ascended Monte Rosa, 
15,217 feet above the sea-level, and who states that “ the 
colour was so deep as almost to approach black. This inten¬ 
sity of colour was only very conspicuous during the last few 
hundred feet of the ascent.” 
Mr. Hincliff, in his ‘ Summer Months among the Alps,’ 
corroborates this statement of Mr. Bonney. These facts, I 
think, strengthen the theory of Professor Tyndall. The at¬ 
mosphere at such heights is more rarilied, and, therefore, more 
free from large particles than it would be nearer the earth. 
It is these large particles which diminish the intensity of the 
blue impression on our vision, by scattering more of the 
larger waves (namely, the red and yellow) into space, in addi¬ 
tion to the blue ones. 
In answer to your correspondent’s fifth question,—it can¬ 
not be proved, experimentally, that “our atmosphere is filled J 
with countless millions of excessively minute particles but 
Professor Tyndall does not go further than to point out that 
all “ the phenomena certainly occur, as if our atmosphere 
were a medium, rendered slightly turbid by the mechanical 
suspension of exceedingly small foreign particles,” and that 
they would not be satisfactorily accounted for on any other 
supposition but this. Again, by producing, artificially, a 
similar condition of matter supposed by this theory, we get 
the same results as we offer to explain, which, to my mind, is 
almost conclusive proof of its probable correctness. 
With regard to my experiment, Dr. Barnsley’s supposition 
of the position of my apparatus is directly contrary to the 
facts. My magnesium lamp was placed at the side of the 
glass vessel containing the suspended particles of gum, and 
the light from the latter, seen by myself and my audience, 
was entirely reflected, and we therefore saw blue. Had the 
vessel been, as Dr. Barnsley remarks, “between the light and 
the retina,” his view would be quite correct, as the colour 
produced in this position was, as Dr. Barnsley states, “ a com¬ 
pound of the prismatic colours, minus the blue.” 
Apologizing for the delay in replying, I have the honour to 
remain, 
Albert Henry Samuel. 
145, Upper Parliament Street, Liverpool, 
December 4 th, 1871. 
Early Closing-. 
Sir,—Seeing that almost every trade, with the exception of 
the druggists, are making endeavours to shorten their business 
hours, I think it is time we took it to heart and tried if we 
cannot get our long period of daily labour shortened, and 
thus afford both to employers and employed a chance of en¬ 
joyment and recreation. No wonder we poor druggists, as a 
majority, look pale and wan, when we are behind a counter 
or in a stinking warehouse or laboratory from 7.30 a.m. to 
10 P.M. 
This is the way to ruin a man’s health. How can an ap¬ 
prentice be expected to study after ten at night P Ilo 
wants to go to bed then, independent of never having any 
out-door recreation. “ All work and no play makes a dull 
boy.” So let us take more recreation, and we shall be able to 
work all the harder and better at the proper time. 
I hope some one may take the matter up as well as myself, 
as I dare say many others are so situated. 
W. S. Stables. 
The Preliminary Examination. 
Sir,—I have read several letters lately respecting the mode 
of conducting the Preliminary examination, and from the 
fact that it is merely an educational test, consider that it 
would give far more satisfaction to the trade at large, as well 
as the candidates, if it were conducted by the College of Pre¬ 
ceptors ; they have, I believe, conducted the Preliminary at 
the College of Surgeons for some time. 
W. P. D. 
November 21s;£, 1871. 
“A Country Chemist .”—You will find your query answered 
on p. 531. 
IP. Dates. — Lococh’s Lotion for the Hair :—Oil of Mace, 
% oz.; Olive Oil, 2 dr.; Water of Ammonia, § dr.; Spirit of 
Rosemary, 1 oz.; Rose Water, oz. Mix. 
T. Bradley .—We believe the book is out of print, but 
second-hand copies may sometimes be obtained. The last 
edition was published in 1849. 
F. J. Hayes .—Apply to the Registrar at 17, Bloomsbury 
Square. 
J. Bienvenu .—The work referred to is not in the Society’s 
Library. We will try and obtain the information. 
“ Pax .”—The subject has been repeatedly discussed in this 
Journal. You will find papers in Second Series, Yol. XI. 
pp. 35, 453, 542. 
B. M. Johnson .—The Act states that the duty shall be 
charged on the packet containing the powders ; it has, there¬ 
fore, in some cases been considered that a person who has a 
licence to sell patent medicines may open a packet of powders 
and sell them separately, but this practice seems to be very 
much like an evasion of the Act, which states that the stamp 
duty is to be paid “ For and upon every packet, box, bottle, 
pot, phial or other inclosure containing any drtegs, herbs, 
pills, tvaters, essences, tinctures, powders, or other prepara¬ 
tions or compositions tvhatsoever, used or applied, or to be 
used or applied, externally or internally as medicines or me¬ 
dicaments, for the prevention, cure or relief of any disorder or 
complaint incident to, or in anywise affecting the human 
body, which shall be uttered or vended in Great Britain.” 
J. HPICnight .—Your communication has been handed to 
the publishers, to whom it should have been sent. 
Communications, Letters, etc., have been received from 
Mr. J. Bradshaw, Mr. A. W. Bennett, Mr. Yewdale, Mr. J. 
Mackav, Messrs. Jones, Palmer and Co., “ Ecosse,” T. A. 
