456 THE POPULAR SCIENCE MONTHLY. 



nean makes up for evaporation less than it does over the Atlantic ; 

 and thirdly, supposing these two questions answered affirmatively : 

 Are not these sources of loss in the Mediterranean fully covered by 

 the prodigious quantity of fresh water which is poured into it by 

 great rivers and submarine springs ? Consider that the water of the 

 Ebro, the Rhine, the Po, the Danube, the Don, the Dnieper, and the 

 Nile, all flow directly or indirectly into the Mediterranean ; that the 

 volume of fresh water which they pour into it is so enormous that 

 fresh water may sometimes be baled up from the surface of the sea 

 off the Delta of the Nile, while the land is not yet in sight ; that the 

 water of the Black Sea is half fresh, and that a current of three or 

 four miles an hour constantly streams from it Mediterraneanward 

 through the Bosporus ; consider, in addition, that no fewer than 

 ten submarine springs of fresh water are known to burst up in the 

 Mediterranean, some of them so large that Admiral Smyth calls them 

 " subterranean rivers of amazing volume and force ; " and it would 

 seem, on the face of the matter, that the sun must have enough to do 

 to keep the level of the Mediterranean down ; and that, possibly, we 

 may have to seek for the cause of the small superiority in saline con- 

 tents of the Mediterranean water in some condition other than solar 

 evaporation. 



Again, if the Gibraltar indraught is the effect of evaporation, why 

 does it go on in winter as well as in summer ? 



All these are questions more easily asked than answered ; but they 

 must be answered before we can accept the Gibraltar stream as an 

 example of a current produced by indraught, with any comfort. 



The Mediterranean is not included in the Challenger's route, but 

 she will visit one of the most promising and little explored of hydro- 

 graphical regions the North Pacific, between Polynesia and the 

 Asiatic and American shores ; and, doubtless, the store of observations 

 upon the currents of this region, which she will accumulate, when 

 compared with what we know of the North Atlantic, will throw a 

 powerful light upon the present obscurity of the Gulf Stream prob- 

 lem. Contemporary Review. 



CONDENSED MILK IN ENGLAND. 



By De. EDWAKD LANKESTEE. 







THE importance of milk as an article of diet is so great that any 

 thing offered as a substitute for it, or that renders it more avail- 

 able as food, demands attention. The composition of cow's milk is so 

 nearly like woman's milk that the addition of a little water and sugar 

 may be said to convert the one into the other ; hence the practice of 

 giving cow's milk to young children, and making it a substantial 



