206 HKPOUT OF r HEMIC AL LA MORATORY 



In many cases the examinations were not carried as far as was desirable, not only 

 liecause of sin^Ie-liamicdncss * in the lulioratory lint cspociiiliy on aeconnt of the want of 

 special tiiemieals ami apiiaratns, atid of the loii),' time wiiicli liad to expire (three to four 

 months) hefore material ordereil from Enf^hiiid or the Continent could be received. Another 

 source of vexation was the continual failure of gas and water supply. Much of the work had 

 to be repeated, in some cases several times, becaiise of this and of the overwhcjiiiing efrccts 

 of sudden sand-storms. Fdrtiiiiatcly tlic latter are not common except in tlu^ Spring and 

 Summer montiis, and as the water and gas supply are now both more constant, it is hoped 

 that the intense annoyances of the past will not be repeated. 



It might not be ann'ss here to sound a note of warning to those who may have to 



undertake the construction of laboratories in out-of-thc-wav iilaccs like the [)rcsent. The 



ihsadkumages nfftvleue gas svstciii. wliili- so altractivelv simple, has, apart fnmi the iiuestion of cost of 



of acclylcne '. . . i > > i i 



for iai>oratory carbide, several disadvantages. It was found that the Hame of the acetylene bunsen is so 



"** hot that breakage of glassware was a very considerable item. This may often be avoided by 



the use of sand-baths or liot plates, or by the interposition of two pieces of wire gauze, 



in place of a single piece, between the glass vessel and the flame. All this entails a 



Efffci of waste of heat. A more serious idijectioii is tlir ell'eit mi |ilatinuiii ware. After exposure 



acelvlene on ..in i * ^ii- 



platinum *" ''"^' """'i'- <"<' surface of tile iilatinuiii in icjiiies of a scalv crystallnie appearance; the 



metal becomes haid and brittle and ultimately cracks. If used in conjunction with a blast 

 the flame is so hot that tlie metal, if thin, may even be melted. 



Our present system is to employ the spirit (alcohol) bunsen for platinum vessels and 

 the acetylene gas for otlier purposes. This is not entirely satisfactory, as alkaline fusions of 

 silicates are dillicnlt by such means.f Later it is hoped that funds may be available for the 

 installaticm of a proper gas system of the ordinary pattern. 



Chemical Composition of the Nile Waters 

 A series of examinations of the waters of the Blue and the White Nile was mnlertaken 



w 



itli a view more especially to (litcniiiiic tlie comparative amounts of suspended matter 

 carried at difl'erent seasons of the year. During my absence in Kurope my instructions in 

 regard to the collection of samples were not carried out, and no determinations were nnide for 

 the month of September, except of a single sami>ie of the White Nile water collected 

 independently by the Depaitiiicnt of Irrigation. The lark of examination of the lilui- Nile 

 during this nuinth is greatly to be regretted, but it is liopcil that it will be possible to nnike 

 a more complete series of observations this vcar. 



The samples from the White Nile were taken from a point about two miles above the 



junction with the Itluc Xjlr. Thosi' of the itlne Nile Wcl-e takill opposite t lie far elld of 



Burre — about a mile beyond the i>uilt-up portion of Khartoum, and about three miles from 

 the junction of the two rivers. In future the samples from the White Nile, especially during 

 the flood, will, if possible, be taken from a point sulFiciently far up the river to avoid the 

 disturbing influer.ce of the Bhm Nile water. 



The figures, which are in many cases the mean of several determinations during the 

 month, express parts per million. 



• This wn» written liefore the a|)poiDtment of Sir. Goodson ns Aatintant Chemist. 



t Wm-e the nlxjve wnx written fusions Imve tioeii efTectcd liy means of Ix;n7.ine and an ordinary blast-lamp 

 The apparatus extemporized for the i)ur|)ose is liKiired and descrilicd on pa^fe 244. 



