F. GEOGRAPHY. 245 



a<res across the Atlantic, in both the northern and southern 

 hemispheres. A careful study of these instruments has en- 

 abled him to determine their rates at sea with such precision 

 that the longitudes of points on the western coast of the At- 

 lantic, especially in South America, deduced from the separate 

 voyages of the Jean JBart, agree within a few seconds among 

 themselves, and equally well with the longitudes determined 

 by what are considered more accurate methods, and published 

 in the French Nautical Almanac. He shows, in fact, that 

 even in voyages lasting two months the navigator should be 

 able to determine his longitude at sea to within three sec- 

 onds of time when employing four chronometers. 6 B, 1873, 

 611. 



FLUCTUATIONS IN THE LEVEL OF LAKE SUPERIOR. 



Professor Whittlesey has given a paper on the fluctuation 

 of the level of Lake Superior a subject specially studied by 

 him many years ago, and which has as yet received but slight 

 elucidation. In his present communication he has confined 

 himself to the consideration of those fluctuations which are 

 not only transient, but also occurring with the regularity of 

 a wave those low pendulum-like pulsations which are prob- 

 ably common to all the lakes, but are most noticeable in Lake 

 Superior. Until a better theory can be found, he adopts the 

 explanation that these undulations are caused by atmospheric 

 movements. Proa. Amer. Assoc, JV. Y. Trib., October 31,1 873. 



EXPLORATION OF LAKE OKEECHOBEE. 



In the number of Forest and Stream for April 6 is pub- 

 lished a letter from Mr. Frederick Ober, under date of March 

 18, announcing the result of an exploration of Lake Okee- 

 chobee, a very little-known body of water in South Florida, 

 around which a halo of romance has been thrown, in conse- 

 quence of mysterious references to ancient ruins of vast ex- 

 tent, and w T onderful forms of animal life, such as spiders 

 weighing several pounds, etc. As might have been expect- 

 ed, however, from a knowledge of the surrounding regions, 

 no such objects w r ere met with, and the ruined cities proved 

 equally to be myths. 



Mr. Ober reports that the only practicable route to Lake 

 Okeechobee is that via Kissimmee River, which is descended 



