F. GEOGRAPHY. 233 



in 18*72, down the Yellowstone Elver and back to Fort Ellis. 

 The surveying party consisted of about twenty men, under 

 the command of Mr. Haydon, chief engineer, and the escort, 

 commanded by Major E. M. Baker, embraced about 375 

 men, making the whole number about 400. The expedi- 

 tion started on the 26th of July, and proceeded through 

 Bozeman's Pass to the Yellowstone Valley, being harassed 

 at almost every foot of the way by the Indians, whose hostil- 

 ity to the enterprise of the construction of the Northern Pa- 

 cific Railroad is such that, according to General Sherman's 

 indorsement, at least two full regiments of cavalry and as 

 many of infantry will be necessary in future to guard and 

 jjrotect the working parties on the railroad. Senate Ex,. Doc. ^ 

 N'o. 16, Forty-second Cong., Third Session. 



THE FRENCH ARC OF THE MERIDIAN. 



The French geodesists of the Topographical Corps of the 

 army have recently, successfully completed the direct junc- 

 tion of the triangulation of Spain with that of Algiers. This 

 has been accomplished by Captain Perrier, who has been able 

 to perceive distinctly from the two high stations in Algiers 

 the two corresponding ones in Spain, although they are dis- 

 tant from each other 200 miles in a direct line. The meas- 

 urements of the bearings of these stations from each other 

 have been conducted with great accuracy. It is very rare 

 that such distant stations can be used in geodetic operations, 

 and the present triangles are said to be the largest that have 

 ever been used in accurate measurements. By the success 

 of the work of Captain Perrier, the famous meridian of Paris 

 has now become a continuously measured arc of over thirty 

 degrees, stretching from the Shetland Islands on the north to 

 Algiers on the south, and its farther continuation southward 

 is evidently only a question of time and money. 



TRANSFER OF SAND FROil AFRICA TO ITALY BY THE SIROCCO. 



As in previous years, Italian meteorologists announce the 

 occurrence of a shower of sand in considerable quantity in 

 the southern part of Italy, consisting in all probability of 

 matter transported by the south winds, or the sirocco, from 

 the African deserts. In one instance,. which took place on 

 the 18th of March, the wind having been blowing for some 



