220 



UKrOKT OF I'llKMICAl, l,A»0«ATOUY 



' Male" and 

 ' female " sail 



fulluwiiig is till uiiiilysis uf suit urystuls tukt-ii from tiic lnil u[ liiike liuuziiiiii'li, in the 

 Waily Natron. 



SiKliuiii Kiil])linU: 004 jut cent. 



Sodium onrbounte o U „ 



True Kiilt (by diff.) 09 85 



The iihovi' iiiiimrity, .slight as it was, was (lerivi'il hirgely from the hiki- water wliieli ainR're<l 



to the surfaff of the crystals. After slight washing in eomiiaratively fresh water, the 



crystals, after drying, had the following composition : 



Sodium Hulplmtc 004 percent. 



Sodium cjirbouiitc ... ... ... 0'04 „ 



True salt 9992 



" .\f,i/i" (Hill " /•ViiKilf" Soil. — We are indebted to Mr. Tiirstig of the Egyptian Survey 

 Department for the following samples which were collected near Khor Tomat, several 

 hundred miles up the Atbara river. At this place salt is extracted from earths wiiiidi 

 contain only a little over two per cent., by leaching with water and boiling dnwii in tlie 

 usual way. 'I'lie interesting point was notid tliat the natives employ for tin ])uipiisf two 

 different earths, one containing what tliey term "male" and the other "female" salt. 

 Neither of these, it was stated, was edible if taken alone, but if the earths are mixed they 

 furnished a salt of good quality. The results of analyses bore out these statements. JOU 

 grammes of each of the earths were found to contain tiic following proportions of soluble 

 salts : 



As will be seen, the " male " salt contains such a large proportion of sodium sulphate 

 as would render it of little use as a table salt. Similarly the "female" salt contains an 

 excessive proportion of calcium chloriile. By combining the two in about the proportion 

 of say two parts of male to one part of female, tlie two impurities would unite to form 

 calcium sulphate, and the })roportion of sodium chloride would be notably increased. On 

 boiling down, the calcium sulphate would separate, in part, and from the concentrated 

 mother liquor a good quality of salt could be obtained by further evaporation. 



Limestone .\Nn T/Ime 



The extension of building operations in the Suilan has created an increasing 

 demand for lime of good cpialitv. Beds of what woulil usually bo considereil to be good 

 limestone are not plentiful, especially in the neighboiu-hooil of Khartoum. Jlost of 

 the deposits are of very irregular character and mixed with more or less, usuaH\- very 



