194 ANNUAL OF SCIENTIFIC DISCOVERT. 



producinf^ a rajiid destruction of the two materials, M'hilst little 

 or no action took place between galvanized iron and the wood. 

 8. The extraordinary resistance which lead offers to the action of 

 sea-water naturally suggests its use as a preservative to iron 

 vessels again;*! the destructive action of that elouKnit; and, al- 

 though we are aware that pure lead is too soft to witlistand the 

 ■w'ear and tear which ships' Ijottonis are suljject to, still we feel 

 that an alloy of lead could be devised which would meet tiie 

 requirements of shii)builders. These results are yet more remark- 

 able when the metals are exposed to a strong tide and a rough 

 sea. Sea-water acts very differently ui>on different brasses, ac- 

 cording to the existence in them of a very small proportion of 

 another metal ; thus, in pure brass the zinc is most rapidly dis- 

 solved (the contrary to wliat takes i)laee in galvanizitl iron), 

 Avhilst it acts as a preservati\'e to the cftpper. Tin, on the other 

 band, appears to preserve the zinc, but to assist the action of sea- 

 water upon the cop])er. The great dilleriuice between the action 

 of sea-water upon jjure cojjper and upon Muntz metal seems to 

 be due not only to tlie fact tliat copper is alloyed to zinc, but to the 

 small propoi'tion of lead and iron wliieh that alloy contains ; and 

 thei'e can be no doubt tliat shipbuilders derive great l)onelit Ijy 

 using it for the keels of tlieir vessels. An alloy of lead, tin, and 

 antimony has been found by Mr. J. Robinson to resist the action of 

 sea-water better than any other metal or alloy. 



COilPAKATIVE ANALYSIS OF THE WATERS OF THE DEAD SEA 



AND THE RED SEA. 



The Water of the Dead Sea. — The Due de Luynes has recently 

 found fishes in the southern portion of the Dead Sea, around the 

 ruins of Sodom, apjjarently multiplying their species comfortably. 

 M. Daubree has analyzed several specimens of the water from 

 vai'ious localities and at dift'erent depths, and has presented his 

 results to the Academy of Sciences of Paris, as follows: — 



1. The density of the Dead Sea increases with the depth. 



2. The composition of the water is not identical throughout its 

 extent, even when those localities near the mouth of the river and 

 the small streams which enter it are excepted. The water taken 

 five miles to the east of Ouadi Mrabba contains four times more 

 lime than that taken five miles east of the Ras Feschkah ; but the 

 latter contains twice as much sodium as the former. 



3. The concentration of the water is also very vai'iable in dif- 

 ferent localities. 



4. The water collected to the north of Sodom, in the jjart 

 which forms a lagoon, contains more chloride of sodium tlian 

 chloride of magnesium, which is the reverse of the ordinary cliar- 

 acter of the waters of the Dead Sea, and explains the i^ossibility 

 of fishes living thei'e. 



5. The proportion of the saline matters remains the same at 

 all depths ; except that the bromides appear to concentrate at 

 dej^ths of 300 metres. 



6. The water of the Dead Sea appears to contain no iodine nor 

 phosphoric acid. 



