610 Transactioxs of the American Institute. 



'. in its pressure, such as would not be obsei'ved in the ordinary 



I barometer, are indicated by means of a dial and moving hand, 



. which may be read as easily as that of a common clock. The 



trouble of making a nice observation, by means of a Venier scale 



on the ordinary barometer, is thus obviated. The aeroscope, with 



its bright tubes and glass dome rising to the height of eight feet 



from the floor, is a handsome instrument; it however occupies more 



room than Hough's self-registering and printing barometer, which 



, furnishes a record of the changes of atmospheric pressure at 



intervals of fifteen minutes through the whole twenty-four hours, 



and this without the aid of human eye or hand. 



ICEBERGS. 



An unusually large number of icebergs have been lately seen in 

 the North Atlantic. One vessel had to sail nearly two hundred 

 miles in a southerly direction, along a perfect continent of ice, 

 while others have met enormous icebergs much further south than 

 they are commonly found at this season of the year. 



JLETEREOGRAPH. 



Among the objects of great interest to scientists in the Paris 

 Exposition, are the diagrams made by the admirable instrument 

 for registering automatically the changes in .the temperature, pres- 

 sure, moisture and motion of the atmosphere, invented by Father 

 Secchi of the College of Rome. 



BISMUTH. 



A bismuth lode has lately been discovered in South Australia, 

 which is said to be very rich, but being two hundred miles in the 

 interior, some difiiculty has been encountered in transporting it to 

 the seaboard. There was also considerable delay in smelting the 

 ore, but a quantity of ingots arrived in England lately, and it is 

 expected that shipments of this rare and valuable metal will here- 

 after be regularly made. 



AMERICAN BREECH-LOADING RIFLES. 



The followinoj are the results of the trials of various breech- 

 loading rifles of American invention, by a foreign military commis- 

 sion appointed to examine them. The Roberts breech-loader fired 

 eighty-four balls in six minutes, an average of fourteen in one 

 minute, each striking inside the target, and penetrating fifteen one- 

 inch boards, laid side by side. The Sharpe rifle fii'ed one hundred 



