1865.] ( 175 ) 



THE BRITISH ASSOCIATION FOR THE ADVANCEMENT 

 OF SCIENCE. 



MEETING AT BATH, September, 1864.* 



It was necessary for us to omit some of the later proceedings of the 

 British Association in our notice of the meeting last quarter, owing 

 to the too near proximity of our day of publication with the meeting 

 of these sections. We now proceed to supply the deficiency by re- 

 cording abstracts of the most important papers, hitherto unrecorded, 

 which were read before the Physical, Chemical, and Natural History 

 sections ; and we may add, that a Geological paper of importance will 

 be found in our chronicles of that branch of science. 



Physical Science. (Section A.) 



On Tuesday, the first paper in this section was by Mr. F. Jenkin, 

 who read the Eeport of the Committee on Electrical Standards. The 

 object of the committee was, first, to select two suitable standards for 

 electrical measurements, and next to decide upon their construction, 

 so as to ensure agreement in measurement. Last year it was deter- 

 mined to measiu'e by units, the fundamental standards being of time, 

 force, and length. The committee now proposed to construct standards 

 and issue them from Kew. Dr. Matthiessen found that lead was the 

 best metal for their reproduction, or, at all events, the choice lay be- 

 tween lead and mercury. 



A discussion then took place on spectroscopes, Mr. Gassiot reading 

 a short paper on the " Adaptation of Bisulphide of Carbon Prisms," 

 and the use of telescopes of a long focal length in the examination 

 of the solar spectrum, with a view of counteracting the difficulties 

 arising from change of temperature. Mr. Browning exhibited a new 

 form of spectroscope, in which direct vision was obtained with a single 

 prism. Professor W. B. Rogers stated that he had heard from Pro- 

 fessor Cooke, of America, who was preparing to replace his bisulphide 

 prisms by glass ones. 



Professor Bogers then described Ritchie's improvements in the 

 liquid compass, as used in the American Monitors. The liquid is a 

 mixture of water and alcohol, and the band of needles is so placed 

 that the disturbances arising from the oscillating motion of the ship 

 is reduced almost to zero. The professor stated that he had seen one 

 of these compasses taken by a porter, who ran with it backwards and 

 forwards, up and down, from side to side of a rough floor, without any 

 perceptible variation in the accurate pointing of the needle ; and it 



* Concluded from vol. i. p. 74(3. 



