Dubois.] "^ [April 2, 



beautifully. My circuit was as follows. My clock breaks the local 

 circuit every second, depriving the helix A of its electricity, and the 

 magnet of its magnetism. This relieves the armature B, which is drawn 

 away by a spring, and the pen C makes its record on the revolving 

 cylinders of the chronograph. At the same instant the main current to 

 Cambridge and back is broken by the insulated prolongation of the arma- 

 ture at D, and the break transmitted to Cambridge and back, through 

 7,000 miles of wire, to my relay E, which relieves the armatvire F, and 

 the local circuit is broken ; the helix G deprived of its electricity and the 

 magnet of its magnetism, relieving the armature H, which is drawn 

 away by a spring, and the pen I makes the record on the revolving 

 cylinders of the chronograph. These two pens are on the same horizontal 

 line. Our experiments show that it took 0.87 of a second to traverse the 

 above circuit. I also made experiments through to Buffalo, Chicago, 

 Omaha, Cheyenne, Salt Lake, and Virginia, and back. All successful. 

 As this experiment was not contemplated by the programme of the longi- 

 tude experiments, I have the satisfaction of seeing my ingenuity success- 

 fully proved. 



Prof. Kirkwood communicated through Mr. Chase a discus- 

 sion of the periodicity of the Sun's spots. 



Mr. Chase made a communication of certain curious rela- 

 tionships of astronomical elements. 



Mr, Dubois presented through Dr. Harris a specimen and 

 analysis of silver ore. 



Mr. Dubois offers the following recent notes from the Assay Office, U. 

 S. Mint: 



By far the largest single piece of silver ever brought to the Mint, was 

 a cake or test-bottom, deposited on the 16th March, by Mr. Christian, 

 President of the Brown Silver Mining Company, of Colorado. Its weight 

 was 4,343 ounces troy, equal to 290 lbs. avoird. nearly. There was a 

 small proportion of gold, and the net Mint value was 5, 720 dollars, silver 

 coin. This was stated to have been extracted from twenty tons of galena 

 in the gangue ; making about 286 dollars to the ton. 



In the Report of the British Commission on International Coinage, 

 lately published, we find an extract from the "Journal des Debats, " of 

 Nov. 13th, 1866, stating that the German assayers had found the average 

 fineness of French gold coins of that year to be 898 thousandths, "and a 

 fraction." It adds that this is an unworthy source of gain to Govern- 

 ment, whose ambition it should be to have the coins correct. 



The "Moniteur" of Nov. 20th (official organ), replies, that this is as 

 near to standard as can be expected from the defects of practical opera- 

 tion ; and that it is the duty of Government to prevent these "ill-founded 

 criticisms." 



