The lathe with its sliding rest is the basis of their stock. With this they can drill, and with the addition of a few wheels can cut screws. The further addition of a vertical slide will enable them to plane small pieces of metal by means of facing cutters on the mandril. By other additions the teeth of wheels may also be cut, and in some rare cases, a lathe may be converted into a small planing machine. The loss of time in making the changes necessary to enable the lathe to fulfil all these different functions, necessarily confines its use to the peculiar classes alluded to above, but to make these changes is often less expensive than to be obliged continually to send to larger workshops where the heavier portion of their work can be executed. It would certainly be desirable, if some good plan cannot be devised for bringing the whole of such operations within the reach of _one_ machine of moderate price, that at least a system should be devised for combining them in _two_ separate machines. Some readers may possibly think such combinations as have been mentioned, too minute and special for the subject of a prize: but when it is considered that they bear upon the interests of one of the best classes of workmen, and how important it is for the welfare of the community that skill, industry, and intelligence should be assisted in their efforts to rise in the social scale, these details will be excused. § The improvements which have been made in the economy of working voltaic batteries, lead to the expectation that they may be employed as sources of artificial light. Although the light thus obtained is not yet sufficiently steady for general use, it may possibly become available for light-houses. Galvanic light offers some advantages for this purpose on account of its intensity and of the facility it affords for darkening and restoring the light, by breaking and renewing the galvanic circuit. But it would be possible to adapt the same principle of occultations to ordinary lighthouses. It would only be necessary to apply mechanism which should periodically pull down an opaque shade over the glass cylinders of the argand burners. This should be instantaneously thrown back by a spring. A series of obscurations corresponding to the digits of any number, and separated by any intervals, might thus be continually repeated. Ready means might thus be supplied of clearly distinguishing one light-house from another. For this purpose it would be necessary to denote the light-houses on any coast by different numbers. Any digit might be expressed by an equivalent number of occultations and restorations of the light: thus— 1 2 3 9 0.0 0.0.0 0.0.0.0, &c., 0.0.0.0.0.0.0.0.0.0 Again, the character of the digit might be indicated by occultations preceded and followed, by shorter or longer intervals of light.