Siphons.—­A flexible tube of some kind, whether of india-rubber, gutta-percha, or, still better, of macintosh, strained over rings, would be very valuable as a siphon:  both for filling large kegs out of buckets and for emptying them again.  Vulcanised india-rubber becomes rotten after short use, and gutta-percha will stand no extremes of temperature.

Tanks for Wagons.—­There still remain many large districts in Asia, Africa, and Australia which may be explored in wagons, but, so far as I am aware, no particular pattern of a water-tank, suitable for carriage on wheels, has yet been adopted by travellers.  I believe kegs are generally used, but they are far too heavy for the requirements of a wagon.  Probably the tins used for sending milk by cart and railway to towns, would be very serviceable for carrying water on expeditions.  They are invariably made of the same shape, and only of few different sizes.  Therefore experience must have shown that their pattern is better than any other yet devised.  Their mouths can be padlocked, which is an important matter.

Macintosh Bags.—­I would also recommend a trial of square bags of strong macintosh—­say 18 inches deep and 10 inches square, in which case they would hold 60 lbs. of water—­fitting into square compartments, in large panniers, like those in a bottle-basket.  I have made some experiments upon this arrangement.  The basket-work gives protection against blows and the jolting together of packages, and it yields without harm to a strain, and the bags yield also.  Moreover, water is less churned in half-empty bags than in half-empty barrels.  No unusual strength of materials would be required in making these bags:  their mouths should be funnel-shaped, and corked at the neck of the funnel.  The funnels should be wide at their mouths, for convenience in filling them; and a string to secure the cork should be tied round the neck of the funnel.  The bags should have loops on their sides, through which a strap, passing underneath, might run, in order to Give a good hold for lifting them up.  They could easily be filled as they lay in their compartments, and would only require to be lifted out in order to empty them; there is, therefore, no objection to their holding as much as 60 lbs. weight of water.  An india-rubber tube as a siphon, and with a common spigot at the end of it, would be particularly useful.  A pannier not much exceeding 30 inches long, by 20 broad, and 18 deep, would hold six of these bags, or 360 lbs. weight of water in all; and two such panniers would be ample for exploring purposes.  I had a pannier and two bags made for a trial, which were quite satisfactory, and I found that the weight of the panniers and bags together was at the rate of 6 lbs. for each compartment; therefore the weight of these water-vessels is not more than 10 per cent.  Of that of the water which they carry.  It might be well to vary the contents of some of the compartments; putting, for instance, two or even three small bags