Dr. AiiDEUSON on the Nutro- Eoro-Cakite. 295 



desirous of ascertaining its exact composition as it occurs. Ulex 

 obtained — • 



Water, 26-0 



Lime, 157 



Soda, 8-8 



Boracic acid, 495 



1000 



If the small per centage of sand and sulphuric acid, and the quantity 

 of lime or soda necessary to combine with the latter, be subtracted 

 from my analysis, the results will be found to approximate very closely 

 to those of Ulex, and to agree well with the formula — 



Na0 2B03 + 2Ca0 3B03 + lOHO. 



The conditions under which this substance is found in loose masses in 

 the nitrate of soda beds, give it a peculiar interest in a scientific point 

 of view, and render it highly desirable that we should have full details 

 regarding the whole circumstances of its occurrence. The district of 

 Tarapaca has been as yet but little explored by scientific observers, but 

 it would appear that it is chiefly volcanic, and it is remarkable that up 

 to the present moment boracic acid has never been found abundantly 

 except in volcanic districts. The commercial interest is equally great, 

 for should the mineral prove abundant it will form an important source of 

 borax, of which the supplies at the present time are by no means great. 

 Nothing can be simpler than to obtain borax from the Natro-Boro-Calcite ; 

 it suffices to boil the mineral in powder with the proper proportion of car- 

 bonate of soda, filter and evaporate, when the borax is obtained in 

 crystals and in a state of great purity. One hundred parts of the sub- 

 stance treated in this way yield about 130 of borax, and as the process 

 could be performed at a cost little, if at ail greater, than that incurred 

 in the purification of the tincal or crude borax of Thibet, it is easy to 

 see that it may become an article of considerable commercial value. Its 

 importance will, however, greatly depend on the quantity in which it 

 can be obtained, but on this point we have at present but little definite 

 information. I learn from the importers that the expense of collection 

 is considerable, and the quantity by no means large ; but it would appear 

 that no very systematic attempts have been made to obtain it in quantity, 

 so that it may possibly be more abundant than it at present seems, and 

 a more extended examination might lead to the discovery of larger 

 deposits. It is possible even that it may occur not merely in masses, but 

 disseminated in minute crystals through the soil, and if this were the 

 case borax might be obtained in larger quantity by lixiviating with car- 

 bonate of soda the residue of the extraction of nitrate of soda. It is also 

 worthy of inquiry whether other compounds of boracic acid and even borax 

 itself may not be found in the same district. 



