SCIENTIFIC SUMMAET. 
1*09 
of different temperature so as to transmute part of their heat into the energy 
of visible motion, just as we do in a steam-engine; and if it is allowable to 
suppose that during this process the moving body has retained all its energy 
of motion, the result will be an increase of the amount of visible energy 
within the enclosure, all the particles of which were originally of the same 
temperature. But Sir W. Thompson has shown that this is impossible ; in 
other words, we cannot imagine an increase of the visible energy of such an 
enclosure, unless we acknowledge the possibility of a perpetual motion. It 
is not, therefore, allowable to suppose that in such an enclosure the moving 
body continues to retain all its energy of motion, and consequently such a 
body will have its energy of motion generally stopped. In this argument 
the use of the enclosure had been to enable them to deduce proof from the 
known laws of heat and energy. We may alter the shape of the body with- 
out affecting the result; in other words, we should expect some loss of 
visible energy in the case of cosmical bodies approaching or receding from 
one another. 
Experiments on Vortex Rings. — Professor Ball made some very interesting 
experiments before the British Association at Edinburgh, on this subject. 
A stream of light was admitted through a lens in one of the shutters, and 
along this stream Professor Ball projected smoke rings, formed on the ejection 
of smoke from a box in which vapour was generated. Professor Tait, during 
the progress of the experiments, alluded to the vibration of the rings when 
those later projected overtook those which had been ejected previously, and 
the latter of which continued to vibrate after the shock. When.Br. Ball had 
concluded his experiments, Mr. B. H. Beacon proceeded with his paper and 
illustrations on vortex rings in water, demonstrating both by diagram and 
actual experiment the formation of secondary and tertiary nodes. The latter 
were made in vessels filled with water, and by means of drops of coloured 
fluids passed thereinto from a tube. These experiments were watched with 
great interest, and were also loudly applauded. The rings were projected 
downwards into the vessels that were standing upon the table, but in answer 
to a question, Mr. Beacon said he had in some cases projected the rings up- 
wards through the fluid, but the phenomena were much more difficult to 
produce. It was also said that similar experiments to those of Professor 
Ball had been made twenty years ago by Professor Boswell Reid, and still 
earlier by Professor Baniell, of King’s College. It was, however, further 
urged that priority in such a matter as this was not of much account, and 
that the value of the communication should be tested by the results attained. 
Unequal Loss of Acid and Salt near the Poles of a Battery. — This is the 
subject of a paper in the u Annales de Chimie.” It is by M. E. Bourgoin, 
who first gives a review of the labours of Baniell, Miller, Pouillet, Hittorf, 
Grotthuss, d’ Almeida, and others on this subject, and next describes at 
length a series of experiments, from which the following main results may 
be deduced : — When the galvanic current passes through acidulated water, 
it will be seen that, though the total effective work done by each pole is 
the same, the quantity of acid found in each compartment at the end of 
the experiment will be found to vary considerably. The three following 
cases may be distinguished : — (1) The acid is accumulated regularly at 
the positive pole; this occurs with sulphuric, nitric, phosphoric, benzoic, 
