INDUSTRIAL PROGRESS DURING THE YEAR 1873. Iv 



The French arc of the merifelian, or the meridian of Paris, 

 has been extended during 1873 from Spain across the Med- 

 iterranean, and now reaches from Shetland in the north to 

 Algiers in the south, an extent of 30. 



A committee of geodesists held a meeting at Vienna during 

 the summer, for the purpose of measuring another arc of the 

 meridian, to extend from Christiania in the north to Palermo 

 in the south, and possibly still farther, across the Mediterrane- 

 an. The object is to establish a new determination of the me- 

 ter, in which all the governments of Europe propose to unite. 

 Although Great Britain was not represented in the congress, 

 it is expected that she will also assist in the enterprise. 



Mr. Gardner, the geographer of Professor Hayden's expedi- 

 tion, has published what he considers an improved method 

 of taking barometric altitudes in the Rocky Mountains. 



Professor Rogers presented a pajDer before the American 

 Association for the Advancement of Science, at the Portland 

 meeting, upon a method of fixing a ship's place at sea, which 

 he considers free from some of the errors which have fre- 

 quently led to so disastrous results. 



Should we include the apparatus for taking soundings at 

 sea under the head of geodesy and hydrograj^hy, we may 

 refer to the sounding-lines used by the Challenger^ which are 

 said to be much stronger than any previously employed. In 

 the construction of these the best Italian hemp was used, 

 subsequently treated with a coating of equal parts of bees- 

 wax and sweet-oil. As the result of this mode of preparation, 

 with a decrease of 15 per cent, in weight of material, an in- 

 crease of strength has been gained of from 100 to 200 per 

 cent.; and the rapidity with which the line runs out is at 

 least 20 per cent, greater than that of lines of tlie old con- 

 struction. 



Another important improvement in sounding-lines is that 

 suggested by Sir William Thomson, in the use of steel piano 

 wire instead of cord, the advantages of which are that there 

 is a much less amount of friction and greater precision of ob- 

 servation. The results of its use by the inventor about Ma- 

 deira and in the Pacific on board the steamer Tuscarora^ in 

 its cruise of the past summer, are such as to show that this 

 apparatus is most valuable and efficient, and bids fair to re- 

 place all others. A weight of from twenty to forty pounds 



