4S4 AMERICAN SCIENTIFIC ASSOCIATION. 



of animals, but in the ovula and ova themselves. And it is in this hin,t science 

 recognizes the real practical utility of this great question. That the Parthenogenesis 

 occupies an important office in the economy of nature we can already perceive, but 

 how it comes to pass that the ova and ovula are developed without the aid of the 

 male principle, and what means are employed to make a sexual reproduction, under 

 such anomalous circumstances, possible, constitute one of those riddles, the 

 solutiou of which is reseiwed for future investigation. 



QUESTIONS CONNECTED WITH THE SALTNESS OF THE SEA.* BY PROFESSOR CHAPMAN, 



OF UNIVERSITY COLLEGE, TORONTO. 



It is a current opinion that, owing to the surface of the sea becoming salter and 

 consequently heavier by evaporation, a downward motion of the surface water 

 necessarily takes place; and hence Lieutenant Maury's hypothesis that the sea is 

 salt in order to produce circulation. Some time ago I suggested another object 

 in explanation of the saltness of the sea, viz. : that the sea is salt in order to regulate 

 evaporation. The greater the amount of salt, the slower the evaporation of the 

 water, — and the reverse ; so that, if by any easily conceivable cause, or combina- 

 tion of circumstances, the normal degree of saltness become either increased or 

 diminished — a kind of self-regulating force is set up to resist the continuation of 

 the abnormal action, until time restore the balance. Even leaving out of considera- 

 tion the equalizing effects produced by the accession of fresh water to the surface 

 of the sea by rain and rivers, it seemed to me that the principle of diffusion was 

 in itself sufficient to prevent the sinking of the water thus affected by evapor- 

 ation ; or, at least, to prevent the sinking of this water to any extent. But how 

 to prove the point. Tne fact that the saltness of the open sea is substantially 

 the same at considerable depths and at Lhe surface, says nothing ; as it would 

 necessarily follow, that for every heavy panicle of water that sunk, a lighter 

 particle would rise up to supply its place ; and hence the composition of the 

 water would be kept uniform, without the principle of diffusion being in any way 

 required to explain the phenomenon. Aiter some consideration I adopted the 

 following method, as one sufficiently trustworthy to afford an answer to the ques- 

 tion under review : — 1 procured a leaden pipe one inch in diameter, and bent into 

 the form of the letter U ; each upright being about thirty-nine inches in height, 

 and the connecting piece at the bottom rather mote than twelve inches long. This 

 I filled up to about an inch on each side with a solution of common salt in rain 

 water (the salt being present to the amount of 3.786 per cent.,) and then I care- 

 fully closed one end, leaving the other end open, but protected from dust by a cone 

 of silver-paper fixed on a bent wire, and so arranged as not to prevent evapora- 

 tion. The per centage of salt (3.186) was carefully ascertained, and the apparatus 

 left in an unoccupied room, the window and door of which were kept almost 

 constantly open, in order to promote the evaporation of the solution as much as 



* It is of course to be understood, that the term " Saltness of the sea," as here applied, has 

 reference solely to the presence of a comparatively large amount of chloride of sodium in the 

 water : to that principle, in fact, which constitutes the essential difference between the waters of 

 the sea and those of lakes and rivers. The other saline substances present in variable propor- 

 tions in sea-water, are present also, more or less, in bodies of fresh-water: und as they neces- 

 sarily subserve the same general purposes in each case, their consideration does not legitimately 

 belong to the present inquiry. 



