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WATER AND THE OCEAN. S7 



depth; and laftly, that the high fea, at a great diftance from ocean 

 land, is falter than near it, and efpecially near places where 



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large rivers fall into the fea. I had no opportunity to make 

 the neceffary experiments to afcertain or to refute thefe alTertions, 

 as I was obliged to fet out upon this expedition almoft at a mo- 

 ment's warning, and could not therefore provide any apparatus ne- 

 ceffary for that purpofe. The above remarks may, however, ferve 

 to future navigators, as a hint of what is flill wanted to be obferv- 



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ed, relative to the faltnefs of the ocean. I fhould therefore pro- 

 pofe to them, to procure the apparatus defcribed by Mr. Wilkcy in 

 thQ Memoirs of the SwediJJj Academy, vol. 33, n, 6 of the ift quar- 

 ter, which ferves to bring the water of the ocean up from any 

 given depth : they ouglit alfo to be provided with an accurate and 



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nice hydroftatical balance, in order to afcertain the fpecific gravity 

 of any water or liquid ; or they may make ufe, for convenience- 

 fake, of a halofcopumy confifting of a hollow globe of ivory, into 

 which a tube of about five or fix inches muft be inferted, on which 

 the dijfferent fpecific weights of pure water, and its various mix- 

 tures with certain quantities of common fait, are marked vn de- 

 grees j fo that, by immerfing this fimple machine into fea- water, 

 it would be eafy to afcertain the degrees of its faltnefs. This ma- 

 chine would likewife ferve to afcertain the comparative purity and 

 weight of every water found in rivers, w^ells, &c. &c. 



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