POPULAR MISCELLANY. 



39 



ment in producing this result. But whether 

 the chance of air-pollution is greater from 

 sewers or from cesspools is not so easy to 

 determine. There are a few records, how- 

 ever, which will help to clear this point. 

 In Berlin, the distribution of cases of fever 

 has been found to be one to each 93 un- 

 sewered, one to each 493 sewered houses. 

 In Dantzic the mortality from typhoid fever 

 dropped to less than one fourth the old rate 

 after the introduction of the sewers in 

 1872, and has been still lower during the 

 last five years. In Cincinnati the water- 

 supply is abundant, but the sewerage is im- 

 perfect, and the death-rate from typhoid is 

 increasing. The city of Mexico enjoys a 

 water-supply of forty-four gallons a day to 

 each person, but there are no sewers, and 

 the fever mortality is very high. 



Various Kinds of Rivers. M. Woeikoff, 

 the Russian meteorologist, considering riv- 

 ers from a climatological point of view and 

 with regard to their sources of supply, makes 

 Beveral types or classes of them. The first 

 are those which derive their waters from 

 the melting of snows in plains or regions of 

 not more than three thousand feet eleva- 

 tion ; such rivers exist only in the extreme 

 north. Next are rivers fed hy the melting 

 of snows in the mountains. Instances are 

 the Amou and Syr Barias, the Tarim, and 

 the upper Indus. In their lower course 

 these rivers traverse regions where it sel- 

 dom rains, or rains only in winter. High 

 waters occur in them at fixed periods, 

 and the maximum height depends on the 

 quantity of snow on the mountains. They 

 are utilized in the plains of their lower 

 course, where cultivation would not other- 

 wise be possible, in vast systems of irriga- 

 tion. A third class of rivers depend on 

 rains, usually tropical and monsoon rains, 

 and reach their maximum in the hot season. 

 They are best represented by the Congo 

 and the Orinoco, in whose valleys snow nev- 

 er falls. They are low in winter, or the dry 

 season, and reach their maximum stage in 

 summer, when immense quantities of rain fall 

 into them. Some of the tropical rivers, like 

 the Amazon, are partly fed by melting snows, 

 but in very small quantity; for the snow 

 exist3 only on mountain-tops above twelve 

 thousand feet in height. To this third class 



belong also the Nile, the Ganges, and Brah- 

 mapootra, and the great rivers of China. 

 That the rivers of China, Mantehooria, and 

 the Amoor region possess the common feature 

 with tropical rivers of having their freshets 

 in summer is a testimony to the prevalence 

 of the monsoons in their regions of supply. 

 To a class that receive most of their waters 

 from rains, but are swollen periodically by 

 the melting of the snows, belong most of 

 the rivers of Western and Northern Siberia, 

 European Russia, Scandinavia, Eastern Ger- 

 many, and the Northeastern United States. 

 The southern hemisphere has no such riv- 

 ers. A fifth class of rivers depend on rain- 

 water, are of constant flow, and are highest 

 in the cold season, without being subject to 

 sudden freshets. They are found in the 

 eastern part of the United States, in New 

 Zealand, and in South America beyond lati- 

 tude 40. Other rivers receiving their wa- 

 ters from rain, and being highest in the cold 

 season, are marked by great differences be- 

 tween high and low water. They predomi- 

 nate in Southern Europe, and are exempli- 

 fied by the Po and Tiber, and by some riv- 

 ers in the United States. Other types may 

 be constituted of rivers which become dried 

 up or lost in their course, and of those which 

 exist as streams for only a part of the year. 

 They are found in desert regions. 



Improvement of onr Climate. Mr. John 

 C. Goodridge, Jr., has suggested a project 

 for modifying the climate of the Atlantic 

 coast by closing the Strait of Belle Isle, 

 and advances the theory that this scheme is 

 feasible as a problem in physical geography 

 capable of an engineering solution. He 

 argues that it is shown by charts that the 

 great body of the "cold wall" comes to 

 us through that strait. Newfoundland de- 

 flects the remainder of the Arctic current 

 to the southeast. Here, pressing against 

 the Gulf Stream, it veers southward in the 

 form of a loop, and finally, running under 

 it, goes on toward the equator. That part 

 of the Gulf Stream that passes our shores 

 has a course directly north and a little 

 west, is deflected slightly toward the east 

 by the coasts of South and of North Caro- 

 lina, and thence turns more to the north 

 again, when it is deflected by the cold cur- 

 rent returning from the pole. When this 



