360 THE POPULAR SCIENCE MONTHLY, 



thus indicated is manifestly sufficient to fill all demands, far into the 

 future years, and this refers only to that which is now on the surface ; 

 while the experience gained at Hachinhama seems to show quite con- 

 clusively that, were all the present store removed, its place would be 

 refilled with a new crop drawn from the inexhaustible resources be- 

 neath. 



To explain the manner in which these separate deposits have been 

 formed is not easy, though in relation to the two borates the following 

 suggestions may possibly be of some avail : If in a broad, shallow, 

 mud-bottomed lagoon, the sodium of which has already formed its 

 combinations with carbonic acid and chlorine, we imagine the process 

 of evaporation to continue until instead of water there remains merely 

 a muddy mass, so far viscid as to be unable to flow from one point to 

 another, and that into this mass boracic acid is forced from beneath in . 

 jets, here and there, only in limited areas, and not extending beyond 

 them, and if we imagine, still' further, that the supply of boron is not 

 sufficient to displace all the carbon and chlorine, we should have car- 

 bonate and chloride existing, intermingled with borate of soda, pre- 

 cisely as we in fact find them, and with a lime-mud we would have the 

 ulexite. 



This may perhaps answer for the borates, but a much greater diffi- 

 culty is encountered when we propose to ourselves the question how 

 the carbonate and the chloride crystallized separately. Over the chief 

 extent they are blended, as they would be left by the evaporation of a 

 lake which held them both in solution. Yet it is also true that, here 

 and there, in areas separated from each other by no elevations what- 

 ever, and which have evidently never been separated, but which must 

 have been parts of the same lake, vast beds of pure salt occur ; while, 

 perhaps, a quarter or half a mile away, carbonate of soda is lying in 

 equally great quantity. How can these masses have been thus placed ? 

 Their bulk demonstrates that in each case quite a considerable depth of 

 solution, even in its most concentrated form, was absolutely necessary. 

 They could not have existed in such juxtaposition and have retained 

 their chemical integrity. 



Could the deposits have been formed at different times? There 

 is nothing to indicate it, nor is the difficulty made less by answering 

 this question in the affirmative. The chloride, in a blended solution, 

 would of course be the last to crystallize, yet there is nothing to 

 cause us to believe that over the carbonate-beds a mass of salt was 

 once formed and subsequently removed. Neither can the two salts be 

 crystallized in bulk, from a united solution, by any means with which 

 we are at present acquainted, and left in the state of separate purity, 

 in which countless thousands of tons are now lying on the deserts of 

 Nevada. 



The question is as difficult as the one why the mud of Borax Lake 

 is filled with the green crystals, while that of Hachinhama has none. 



