February 18 , 1871.] THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
671 
various adulterants. With regard to the donation they 
had received from Thomas Hyde Hills, Esq., part of the 
looks purchased with the above donation of £5 would 
he to hand in a few days, and would then be allowed 
to circulate. Mr. Hills had also kindly presented to 
them copies of the portraits of the late Mr. Jacob Bell, 
Dr. Pereira, and Mr. William Allen. The grant from 
the Pharmaceutical Society, of which they had already 
heard was in part disposed of in purchase of those 
diagrams now of so much service to the botanical class. 
They intended shortly to expend the remainder in the 
purchase of chemical diagrams. He had been re¬ 
quested to notice the falling off in the attendance at the 
various classes. It had caused him much pain and sur¬ 
prise that those for whose benefit they were carried on 
should not have more earnestly availed themselves of 
then advantages. It was quite unnecessary to enlarge 
upon these advantages, under the present system of com¬ 
pulsory examination, but he would remind them that 
they were throwing cold water on the efforts of those 
gentlemen who had so kindly given up much of their 
time, not only for the actual delivery of the lectures, but 
for their preparation. He trusted that those present 
would incite the habitual absentees, and that in the 
future there would be a marked improvement. 
The Chairman stated that Mr. Butler had consented 
to act as Financial Secretary. 
Mr. Grimditch was elected Secretary. 
The meeting closed with a vote of thanks to the 
Chairman. 
LIVERPOOL CHEMISTS’ ASSOCIATION. 
The Eleventh Conversasione of the Liverpool Chemists’ 
Association was held on Thursday evening, February 3, 
at the Royal Institution, Colquitt Street, and was very 
numerously attended. The entire building was thrown 
open to the company, and the many objects of interest 
in the collections connected with the institution were 
supplemented by others lent for exhibition on this occa¬ 
sion by various private gentlemen and public societies. 
Mr. Albert H. Samuel, several times during the 
evening, explained and illustrated experimentally Tyn¬ 
dall’s theory of the blue colour of the sky. He prefaced 
his explanatory remarks by shortly noting the fatal ob¬ 
jections to the other theories previously accepted, and 
then proceeded to explain that all space is filled with an 
extremely subtle and elastic medium to which the name 
“ether” is given. He then defined light as the result of 
an infinitely rapid vibratory motion of the molecules of 
luminous bodies, such as those of the sun. These vibra¬ 
tions give to the ether a wave-like motion, which strik¬ 
ing on the retina of the eye produces a certain sensation 
which we call light. The waves of ether are of different 
lengths and amplitudes. The greater the amplitude the 
more intense the light. It is the difference in the length 
of the waves, which gives us the impression of different 
colours, blue being- caused by the shortest waves, and red 
by the longest. The long red waves have also a much 
greater amplitude or depth than the short blue waves, 
and are thereby enabled to roll over or pass by small 
obstacles which would interrupt and throw back the 
short and shallow blue waves. He then stated that our 
atmosphere is supposed to be filled with countless mil¬ 
lions. of excessively minute particles, in a state of sus¬ 
pension, and that the long deep red waves roll or pass 
over these small particles, but the short shallow blue 
waves , are stopped by them, and thrown back or scat¬ 
tered into space, to which they communicate the blue 
appearance which we call sky. He then proceeded to 
demonstrate this theory by drawing the attention of his 
audience to a large glass vessel of water in which he 
had suspended, by means of an alcoholic solution of gum 
mastic, an infinite number of minute particles of the 
gum. 
On bringing the powerful light of a magnesium lamp 
to bear on the particles, the water at once assumed the 
characteristic blue appearance of the sky,—the water 
representing the ether, and the suspended particles of 
gum, the infinitely minute particles floating in our at¬ 
mosphere. 
In the course of the evening the company assembled 
in the Lecture Theatre, to listen to an address by Pro¬ 
fessor Roscoe, illustrated by experiments on “Solar 
Chemistry.” 
Mr. Abraham, who occupied the chair, in introducing 
the lecturer, reminded the audience that fifty years ago 
the institution in which they were assembled was opened 
by William Roscoe, the most distinguished ornament to 
literature the town had produced. Professor Roscoe, 
however, might be introduced upon his own merits. 
Professor Roscoe, after thanking the meeting for the 
flattering manner in which it received him, and the Pre¬ 
sident for the kind way in which he spoke of his honoured 
grandfather, said,—The science of astronomy was most 
important. The sun had, from the earliest times, at¬ 
tracted attention, and even worship ; but very little had 
been known concerning it until within the last few 
years. Recently, however, this knowledge had increased. 
Now we know something, not only of its physical con¬ 
stitution, but of its chemical composition; that the sun 
contains substances found on the earth ; that iron, mag¬ 
nesium, and many other elements are present in the 
solar atmosphere. When it was remembered that the 
sun was 91,000,000 miles distant from the earth, it 
seemed a marvel that such information could be obtained. 
Light and heat form the only medium of communication 
between this world and the sun. It was by examining 
the light emitted by the sun that the composition of the 
solar mass could be ascertained. White light is a com¬ 
pound, whereas coloured light is a simple phenomenon. 
If light were of only one colour, or monochromatic, 
colour would not be seen at all, but would appear as 
different degrees of shade. With the aid of the spectro¬ 
scope, the professor illustrated the different character¬ 
istics of the solar rays. The glowing vapours of the 
gases were beautifully shown, also the broken spectrum 
caused by throwing lithium through the prisms, and 
the effect of thallium. He next volatilized several metals, 
such as silver, copper, cadmium, tin and sodium, and 
showed the lines produced by each, observing that, how¬ 
ever distant a light might be, it could Jbe ascertained 
what metal produced it. He then said that there were 
blue and orange-coloured stars, showing a different kind 
of light, and the linos produced by them were different 
from those produced by the sun; while those produced 
by the planets and the moon, being from borrowed light, 
were the same, showing that these stars were self-lumi¬ 
nous. Kirchhoff came to the conclusion that metallic 
vapours existed in the solar atmosphere, and that certain 
lines in the solar spectrum were due to the presence of 
metals in it. Since Kirchhoff’s discovery, their know¬ 
ledge of the sun had greatly increased. The lecturer 
next proceeded to explain a few of the phenomena at¬ 
tending a total eclipse of the sun. He said they were 
most marvellous and difficult of explanation. By means 
of diagrams he illustrated the red prominences observed 
during a total eclipse. The Himalaya expedition in 
1860, proved that these protuberances belong to the sun. 
They consist of glowing masses of hydrogen, many of 
which are supposed to extend 80,000 or 90,000 miles, 
and move with wonderful rapidity'. Speaking of the 
oorona or white halo of light seen outside the sun during 
a total eclipse, the irregular form of which extended into 
space, he said the result of the recent eclipse expedition 
was, on the whole, satisfactory'; for in spite of bad 
weather, accidents and mishaps, the corona had been 
run down at last, and it was pretty' well known what it 
was. If, however, the astronomers had been favoured 
with fine weather an important series of observations 
would have been made at Syracuse. Some of them went 
up Mount Etna, and saw nothing. About half an hour 
