August i8, 1892] 



NAT ORE 



383 



Prof. Lodge opened the discussion by giving an outline of the 

 work which might be done in such a iaboratory. The work 

 should include the accurate determination of physii;al constants, 

 the maintenance of standards, and the issue or verification of 

 certified copies, the continuous recording of certain special 

 phenomena, the conduction of certain special experimental 

 inquiries, more particularly such as might have to be carried on 

 years or even centuries ; the taking up and completing of lines 

 of research already developed by amateurs (or even in well- 

 equipped laboratories) to that point at which it was impossible 

 for them, unaided, to proceed farther. 



Mr. Glazebrook described the work done at the Cavendish 

 Laboratory. A part of this work consists in the testing of 

 units of electrical resistance and electromotive force. In many 

 cases it is quite impossible (in view of the more proper work of 

 the laboratory) to give the necessary time for the proper carry- 

 ing out of this work — which should be undertaken by a National 

 Laboratory. 



Prof, von Helmholz stated that one of the chief causes for the 

 setting up of the National Physical Laboratory at Berlin was 

 the desire of the Government that mechanicians should be 

 assisted in their work by means of properly conducted scientific 

 research and superintendence. It was necessary also that 

 proper headquarters should exist for the construction and control 

 of standards. The directors are entirely free from any duties 

 of teaching, no systematic instruction being given in the 

 laboratory. A large part of the work done consists in standard- 

 izing of thermometers. In the first year of the institution 90,000 

 were tested. Electrical apparatus, steam engine indicators, and 

 standard lights for gas and electric companies, are also tested ; 

 and a considerable amount of thermodynamical work is under- 

 taken with a view to practical improvements. ;^2500 are 

 spent annually upon apparatus and work alone, exclusive of 

 salaries. 



Lord Kelvin said that it was a matter of great importance to 

 the nation that its artizans should have as good scientific direc- 

 tion for their work as the artizans of Germany have for theirs. 



Prof. Riicker said that it was by no means gratifying that it 

 was necessary to send thermometers to Paris in order that they 

 should be compared with the air thermometer. It would be of 

 great advantage to have a national institution worked largely in 

 connection with the Royal Society. 



Prof Fitzgerald, among other things, said that he doubted 

 if the House of Commons was sufficiently educated to under- 

 stand that the advance of scientific work was of national 

 value. 



The Discussion on Nomenclatwe of Units was opened by 

 Prof. Oliver Lodge on lines recently indicated in Nature. 



Dr. Hopkinson and Dr. Preece criticized the proposed 

 changes, maintaining that the time had not yet arrived when 

 they could be advantageously introduced, even if they were 

 satisfactory, which was very questionable except in one or two 

 cases. 



Dr. du Bois also spoke in opposition to the proposed 

 changes, remarking that, even if accepted in Britain, they 

 certamly would not be favoured in Germany. The discussion 

 then dropped. 



The Report on Underground Temperature dealt with obser- 

 vations made in a boring at Wheeling, West Virginia. The 

 well had been sunk by a company to a depth of 4500 feet. The 

 company decided to abandon it at this stage ; but on request 

 the boring was continued to a much greater depth for the pur- 

 pose of the scientific observations. During last summer obser- 

 vations of temperature were made at successive depths of 125 

 feet down to the bottom. The surface temperature being 51°, at 

 a little more than 1000 feet below the surface, 68' 75 were regis- 

 tered. At 3000 feet and 4000 feet respectively, 87° and 102'^ were 

 observed ; and at the bottom of the well the temperature was 

 no '15. The rate of increase grows with the depth. Between 

 1590 feet and 1835 feet, the average rate was i'' per 92 feet ; 

 between 1835 feet and 2486 feet it was 1° per 84'5 feet. This 

 increased until at the foot the rate was i" per 58 feet. The 

 average rate was i' per 72 feet. 



Report on the Discharge of Electricity from Points. — As the 

 result of the experiments made it was found that disturbing in- 

 fluences, which had little or no effect at the cathode, had a 

 powerful effect when applied to the anode, so as even to pre- 

 vent the passage of sparks. Experiments were also made with 

 the view of determining the quantity of gas concerned in the 

 passage of a given quantity of electricity. 



NO. I 190, VOL. 46 J 



Report on Electrical Standards. — The committee which sub- 

 mitted this report had a meeting at Edinburgh, which was 

 attended by a number of foreigners. As a result of this meeting 

 they agreed to the following resolutions :—(i) That the resist- 

 ance of a specified column of mercury be adopted as the 

 practical unit of resistance ; (2) That I4'452i grammes of 

 mercury in the form of a column of uniform cross-section, 

 106-3 cm. in height, at o C, be the specified column; (3) 

 That standards in mercury, or solid metal having the same 

 resistance as this column, be made and deposited as standards 

 of resistance for industrial purposes ; (4) That such standards be 

 periodically compared with each other, and also that their values 

 be redetermined at intervals in terms of that of a freshly set up 

 mercury column. It was further agreed that these resolutions 

 be communicated to the Electrical Standards Committee of the 

 Board of Trade. It was agreed that the number 0"00i 118 should 

 be adopted as the number of grammes of silver deposited per 

 second from a neutral solution of nitrate of silver by a current 

 of one ampere, and that the electromotive force of a Clark cell 

 at 15'C. should be taken as I 434 volts. 



Prof von Helmholz remarked that a column of mercury was 

 much preferable to alloys, in which small fissures might exist or 

 come into existence. He alluded also to the manner in which 

 the difficulties of setting up such a meicury column, arising 

 from the want of proper contact between the mercury and the 

 glass, may be overcome. The British and German tests agreed 

 so closely as to show that the results might be used for com- 

 mercial purposes, possibly for centuries ; though, for scientific 

 purposes, some change might be needed. He and others had 

 been sent here by their Government with the object of coming 

 to an agreement on this subject with Great Britain, and it was 

 hoped that America and France would also adopt the 

 resolutions. 



Wire Standards of Electric Resistance, by Dr. Lindeck, of 

 Berlin. — The author described experiments on this subject. 

 Alloys containing manganese seem to be the best for the purpose. 

 Those containing zinc are the most objectionable because of im- 

 purities. Changes of resistance depending on the process of 

 winding the coils were also investigated. The best results were 

 got with the alloy manganin. Changes of resistance, apparently 

 due to oxidation from contact with the air, take place ; but these 

 can be avoided by varnishing the wire. The resistance rises 

 slowly with temperature, reaches a maximum, and then decreases 

 rapidly. 



Prot. Sylvanus Thomson said that, in working with manganin, 

 he had found that it could not be relied upon if too strong a 

 current were sent through it. He agreed that no alloy contain- 

 ing zinc should be used. 



On the Clark Celt, by Dr. Kahle, Berlin.— Dr. Kahle gave 

 details of experiments made on Clark cells. He found that they 

 furnished a very trustworthy standard of electromotive force, and 

 that they were very suitable for practical work. 



Prof. Carhart said tnat he had found cells, made by different 

 persons at different times, gave practically the same result when 

 used under the same conditions. 



Mr. Glazebrook said that he had come to the conclusion that 

 differences amongst the results given by different cells were due 

 to the fact that the time taken to reach the equilibrium condition 

 differed in different cells. 



Preliminary Account of Oceanic Circulation, based on the Chal- 

 lenger Observations, by Dr. A. Buchan. — In communicating 

 this account, Dr. Buchan remarked that the enquiry had so far 

 advanced that the chief results could be stated. The Challenger 

 observations have been supplemented by those of Mohn, Agassiz, 

 J. T. Buchanan, Belknapp, and Capt. Wharton. The surface 

 winds of the globe have a special bearing on the subject of ocean 

 temperature. The surface winds of the Atlantic generate cur- 

 rents which have the effect of raising the temperature on the 

 west side of the Atlantic, at depths from 100 to 500 fathoms, 

 about 10 degrees above the temperature at these depths on the 

 east side. At 500 fathoms the temperature is nearly the same at 

 both sides of the Atlantic, but at loA-er depths the effects are re- 

 versed. At these depths the west side is more under the influ- 

 ence of the Arctic currents along the American coast, and the 

 east side is more under the influence of the under currents frorc. 

 the Mediterranean and the equatorial regions of the Atlantic. 

 This high temperature distribution extends northwards even 

 beyond the Wyville Thomson ridge between Shetland and Ice- 

 land. At 700 fathoms the temperature jus; south of this ridge is 

 five or six degrees higher than it is over the Pacific, Indian, and 



