There is no better drink than tea, poured out and left to cool, and drunk without sugar.

You might take a dozen tins of preserved milk, as many of condensed cocoa and milk, and a couple of dozen pots of jam.

Of course, you could not take all these things on if you were likely to move, but you may be at Dongola some time, before there is another advance, and you may as well make yourself as comfortable as you can; and if, as is probable, you cannot take the pots up with you, you can hand them over to those who are left behind.
You will have no trouble in getting a fair-sized case taken up, as there will be water carriage nearly all the way.
"A good many fellows have aerated waters sent up, but hot soda water is by no means a desirable drink--not to be compared with tea kept in porous jars; so I should not advise you to bother about it.

You will want a water bottle.

Get the largest you can find.