8§0 Transactions of the American Institute. 



river of the north. This report has not been published, but is 

 believed to be favorable. Lake Traverse lies south of the dividino: 

 ridge, yet, flows through it into the Bois de Sioux. The distance 

 from the head of Lake Traverse to the head of Big Stone Luke, 

 which empties into Whetstone river, a branch of the Minnesota, is 

 less than ten miles. A short canal would unite these lakes. Otter- 

 tail lake, and many other lakes, including Elbow lake which lies 

 about forty-seven degrees north latitude, discharge their surplus 

 waters into the main branch of the Red river of the north. But 

 little definite knowledge of the topography of the country can be 

 obtained from our present maps. The whole surface is nearly 

 level. It does not seem impossible to dam the Red river at or 

 near Breckinridge, and cause all the waters of its main branches to 

 be discharged into Big Stone lake, thus forming a water communi- 

 cation between Elbow lake and the Mississippi river. 



HYDRATE OF BI-SULPHIDE OF CARBON. 



M. Duclaux, a French chemist, has lately produced a new com- 

 pound, which consists of two atoms of bi-sulphide of carbon and 

 one atom of water (alU-eros), 



A GREAT REFRACTOR. 



Mr. Cooke, of London, has just completed a twenty-five inch object 

 glass, the largest yet made. The telescope has been subjected 

 to the usual tests in resolving celestial, objects, and is pronounced 

 optically excellent. 



CONCENTRATION OF THE SUN's HEAT. 



The lens recently made for Mr Parker, of London, is three feet 

 in diameter, three inches thick in the center, and weighs 212 

 pounds. In its focus small quantities of the most refractory metals 

 are quickly fused and completely dissipated into vapor, and the 

 usually unyielding minerals are immediately vitrified. 



THE DISTINCT ACTION OF ACTINIC AND LUMINOUS RAYS. 



The photographs taken in England during the lunar eclipse on 

 Sept. 13, do not represent a certain portion of the moon seen with 

 the telescope. Mr. De la Rue has well exjDressed the nature of this 

 peculiarity, by saying that more of the moon is cclij)sed chemically 

 than optically. 



NEW SENSITIVE COiVIPOUND. 



M. Prat, who claims to have isolated fluoride, forms a fluorine of 

 silver insoluble in water, and soluble in ammonia from which it i3 



