Red Sea. 



1-80 



0-82 



81-95 



335 



510 Analyses — Sea- water — Magnesia. [Sept. 



Arabian Sea. 



Sulphuric acid, thrown down with barytes, L82 grs. 



Lime, precipitated by oxalate of ammonia, 0'70 



1000 grs. gave, with nitrate of silver, 



chloride of silver, 8000 



=: chloride of sodium, or common salt, 32" 8 



Although, however, the sea in mid channel may not differ materi- 

 ally from the broad ocean in its contents, it may be possible that in 

 insulated positions near shore, under a fierce sun, concentration may 

 proceed to a considerable extent — this is the only way in which I 

 can account for the very different result published in the London 

 Literary Gazette, on the authority of Dr. Uue's analyses quoted in Mr. 

 WiXiKiNSON's work on Egypt. 



The following is the paragraph alluded to : 



" During my stay on the coast of the Red Sea, I had occasion to 

 observe the remarkable saltness of its water, and succeeded in ascer- 

 taining that it contained much more saline matter than the ocean. 

 I have since been favoured by Dr. Ure with the analysis of some 

 water brought by me from Berenice, from which it results that the 

 specific gravity is l - 035 ; that 1000 grains of water contain 43 of 

 saline matter, of which about four grains are muriate of lime, with 

 a little muriate of magnesia, and the remainder muriate of soda, with 

 a little sulphate of magnesia. The specific gravity of water of the 

 open ocean in the same latitude is only 1*028, and contains not more 

 than 36 grains of saline matter in a similar quantity." 



To which the author attaches a note, explaining, that " after the 

 vernal equinox, the Red Sea is lower in winter ; but the prevalence of 

 the south wind after the month of September causes a considerable 

 rise of its level." 



The difference in the two cases is not more than may reasonably 

 be explained in the above manner. The hydrometer is in all cases 

 the safest test, and it is a pity that it had not been resorted to in the 

 steam navigation of the Mediterranean, which has been the source of 

 such contradictory statements. 



2. — Native Carbonate of Magnesia from South India. 

 In my analysis of the Nerbudda dolomite, published in the Gleanings 

 in Science, vol. I. p. 267, I expressed a desire to obtain some of this 

 mineral, stated by Dr. Thomson to form " whole rocks in Hindustan, 

 and to contain much less carbonic acid than it ought," though he was 

 curious to know whether the interior portions of the mountain might 

 not have their full proportion. 



My wish has at length been gratified by Dr. Malcolmson, Sec. 

 Med. Bd. at Madras, among whose specimens, recently presented to 





