468 
LEEDS CHEMISTS’ ASSOCIATION. 
nient distance behind it, and the object as near as possible in the true focus. He further 
spoke of the advantage that would be likely to be gained chemically from the extension 
of microphotography in the detection of adulteration, or in extending our acquaintance 
with the structure of rare bodies. 
A vote of thanks to Dr. Edwards concluded the business of the evening. 
LEEDS CHEMISTS’ ASSOCIATION. 
The Fourth Meeting of the session was held in the Library of the Philosophical So¬ 
ciety, on the evening of January 11, 1865 ; the President (Mr. Haigh) in the chair. 
Dr. Clifford Allbutt, one of the physicians to the General Infirmary, etc., very kindly 
delivered to a large meeting of the members and their friends a discourse upon 
“ Vitality, or the Correlation of Physical and Vital Phenomena.” The following is a 
slight sketch of the lecture, which commenced by an allusion to the present advanced 
status of those engaged in the practice of pharmacy, giving them the claim to recog¬ 
nition from the physician as intelligent and indispensable allies, to whom he was con¬ 
stantly indebted for the introduction of improved remedies. 
The lecturer then spoke of the ideas formerly held as to the condition of matter in a 
state of rest, viz. that it implied the negation of force, to which the term inertia was 
given. All inorganic bodies were supposed to have such a negative condition as their 
normal one. Now, however, rest is defined as the state of equilibrium between various 
contending forces. This balancing or neutralization of force is termed tension. A piece 
of chalk lifted in the hand is in a state of tension, since gravitation would draw it to¬ 
wards the earth, whilst muscular force, resulting from the complex operations of animal 
life, keeps it elevated. When it is allowed to fall, gravitation obtains ascendancy, 
tension is destroyed, and we speak of the resulting manifestation of force as energy. 
Illustrations of the same truth are found in the machinery of a watch and in a cross¬ 
bow, etc. We may define the motion seen to occur in all these instances as the con¬ 
version of rest into energy. 
The thermo-electric pile and astatic galvanometer were introduced to show the trans¬ 
formation of heat through electricity into motion. A multiplying-wheel gave friction 
to a brass tube containing ether, which boiled and exploded its cork. An electric telegraph 
instrument showed the conversion of chemical affinity exerted in the battery into gal¬ 
vanism and motion in the index. The conversion of motion into magnetism in the 
well-known experiment with a poker, and other illustrations were alluded to, establishing 
and elucidating the doctrine of the correlation of force. 
The indestructibility and conservation of force were next treated. One of the simplest 
cases is that of a falling body, where the force exerted in the fall appears to be lost 
when it is arrested, but when carefully observed is shown to have taken the new form of 
heat. Mayer’s mechanical theory of heat is the expression of such facts, which are more 
precisely exemplified in the experiments of Joule, who found that one pound falling 772 
feet raised a pound of water 1° F. in temperature. Shooting-stars have been calculated 
to attain a temperature of 360,000° F. by friction against our atmosphere,—a heat suffi¬ 
cient to dissipate their most solid constituents into gases of the greatest tenuity. In 
recent target experiments at Shoeburyness, flashes of light were seen which were attri¬ 
buted to volatilized iron. 
The relations of force and matter were treated on by the lecturer, who showed that 
neither could exist without the other, and that each atom of matter formed a centre of 
force. Isomerism presented a most interesting field for inquiry as to how the same 
atoms could by different grouping present very various results. 
Applying the doctrine of the correlation of force to vital manifestations, it was shown 
that man can no more exist surrounded by these forces, and still be independent of 
them, “ than can iron be placed in the fire without becoming hot.” We have got ac¬ 
customed to think and speak of vitality as some distinct internal force belonging to 
living beings. We now know that the physical phenomena of animal life can be ex¬ 
plained by the laws governing external forces, and may anticipate the time when it will 
be determined experimentally how much force an animal absorbs, and how much it 
gives out again. We may rest assured that the amounts will be found to be equal. In 
