generally in Australia. A long bar is crossed by a short one near one of its ends,-this latter forms the axle tree ; the body of the dray is built where the two cross ; and the cattle are yoked or harnessed to the long end of the bar, which acts as a pole.
Tarring Wheels.-Tar is absolutely essential in a hot country, to mix with the grease that is used for the wagonwheels. Grease, alone, melts and runs away like water : the object of the tar is to give consistency to the grease: a very small proportion of tar suffices, but without any at all, a wagon is soon brought to a standstill. It is, therefore, most essential to explorers to have a sufficient quantity in reserve. Tar is also of very great use in hot dry countries for daubing over the wheels, and the woodwork generally, of wagons. During extreme heat, when the wood is ready to crack, all the paint should be scraped off it, and the tar applied plentifully. It will soak in deeply, and preserve the wood in excellent condition, both during the drought and the ensuing wet season. (See " Tar, to make.") It is not necessary to take off the wheels in order to grease the axles. It is sufficient to bore an auger-hole right through the substance of the nave, between the feet of two of the spokes, and to keep a plug in the hole. Then, when you want to tar a wheel, turn it till the hole is uppermost, take the plug out, and pour in the tar.
Breaks and Drags.-Breaks.-Every cart and wagon in Switzerland, and, indeed, in
most parts of the Continent, has a break attached to it: the simplest kind of break is shown in fig. 2, which represents a cart tilted upwards Fig 1 shows
the break itself ; fig. 2 explains M
how it is fitted on to the cart. It will easily be understood how, by tightening the free end of the cord, the break is pressed against the wheels. The bent piece of iron shown in
fig. 2, by which the bar of the break is kept in its place, may