At the meeting of the British Association at Glasgow in 1840, Mr. H. Dircks exhibited a wheel of a novel construction, invented by him, which had been running for several weeks on the St. Helen's railway with very satisfactory results. The construction of the wheel will be understood by imagining an ordinary spoked wheel, but with a deep channelled tyre, as seen in Fig. 2. In this channel are inserted blocks of African oak, measuring about 4 in. by 3 1/2 in., prepared by filling the pores with unctuous preparations, to counteract the effects of capillary attraction in regard to any wet or dampness, by which it becomes impervious to either. There are about 30 of these blocks round each wheel, cut so as to fit very exactly, and with the grain placed vertically throughout, forming a kind of wooden tyre, each block being retained in its place by one or two bolts Figs. 3 and 4, the two sides of channel having corresponding holes drilled through them for this purpose. The bolts are afterwards all well riveted. After being so fitted, the wheel is turned in a lathe after the ordinary manner of turning iron tyres, when it acquires all the appearance of a common railway wheel, but with an outer wooden rim, and the flange only of iron.
Mr. Dircks proposed using either hard or soft woods, and various chemical preparations to prevent the admission of water into the pores of the wood; he also contemplates the using of compressed woods.
The annexed figures represent one of these wheels, Fig. 1 being a front elevation, (partly in section.) and Fig. 2, a vertical section through the line Z. a is the boss; b b the arms; and c c the rim or felly of the wheel, having deep flanches d d on each side, forming a circular groove or trough round the periphery of the wheel. In this groove or trough are inserted the blocks of wood e e (before mentioned), which are retained in their places by bolts ff passing through them, and riveted outside the flanches. The several advantages which this wheel possesses, are represented by him to be, - that the wooden tyre will wear a considerable time without requiring any repair; that the tyre can be refaced by turning it up again in the lathe, as practised with worn iron tyres; that it can be re-tyred with wood at little expense, and at a far less loss of time than usual; and that both in the operations of refacing old tyres, or putting on new wood, the work can be performed without the usual labour and cost of unkeying, as the whole can be done while the wheels remain on the axles.