and Littoral Manganese Nodules 



183 



In connection with these Tables it may not be amiss to 

 quote the analyses which I made of some nodules in 1876, and 

 published in the Proceedings of this Society 1 . The samples 

 analysed were from four different localities, two of which are 

 identical with those from which the nodules I-V came. 



Nos. 2, 4, and 5 were from the same place, No. 2 being the 

 matter collected round a shark's tooth as nucleus ; Nos. 4 and 

 5 being the outside rinds of ordinary nodules. 



The results are given in the following Table, the numbers 

 being in many cases the means of several observations: 



A is the residue which remains undissolved after treating 

 the mineral with strong hydrochloric acid, evaporating to 

 drvnt-ss and redissolving. In No. 5 it contains 85-16 per cent. 

 i, and in Xo. 6, 82-27 per cent. 



B is the available oxygen determined by Bunsen's method. 



C is the MnO 2 equivalent to the available oxygen. 



D is the MnO found by weighing as Mn 3 O 4 . 



E is the Fe a O 8 found by titration with SnU,. 



th- .ilumina found by subtracting the Fe^ found in 



rom the weight of the precipitate with ao-tati- <f soda. 



G is the water expelled on ignition; it is obtained by 

 deducting two-thirds of the oxygen found in B from the loss 

 of weight by ignition. 



The samples were dried for ten or twelve hours at 140 C., 

 and therefore the percentages are hight r than tlu.M in Table IV, 

 the It :n it having luvn anal\M-d air-dried. 



1 Pfoc. Roy. Soc. Edin. 1876, vol. ix. p. 287. 



