24. _Carpinus betulus_, L. (hornbeam).--A tree from 20 to 70 feet high, with a trunk sometimes 10 feet in girth, indigenous in the southern counties of England. The wood is very tough, heavy, and close grained. It is largely used in France for handles for agricultural and mining implements, and of late years has been much used in this country for lasts. The wood of large growth is apt to became shaky, and it is consequently not used as a building wood. It is said to have been used as a substitute for box in engraving, but with what success does not appear. 25. _Ostrya virginica_, Willd (ironwood, or American hornbeam).--A moderate-sized tree, widely spread over North America. The wood is light-colored, and extremely hard and heavy; hence the name of ironwood. It is used in America by turners, as well as for mill cogs, etc., and has been suggested as a substitute for boxwood for engraving, though no actual trials, so far as I am aware, have been made with it. Besides the foregoing list of woods, there are others that have been occasionally used for posters and the coarser kinds of engraving, such, for instance, as lime, sycamore, yew, beech, and even pine; and in America, _Vaccinium arboreum_ and _Azalea nudiflora_. Of these, however, but little is known as to their value. It will be noticed that in those woods that have passed through the engraver's hands, some which promised best, so far as their texture or grain is concerned, have been tried upon very imperfect or badly seasoned samples. The subject is one of so much importance, as was pointed out at the commencement of this paper, that a thoroughly organized series of experiments should be undertaken upon carefully seasoned and properly prepared woods, not only of those mentioned in the preceding list, but also of any others that may suggest themselves, as being suitable, It must, moreover, always be borne in mind that the questions of price, and the considerations of supply and demand, must, to a great extent, regulate the adaptation of any particular wood. With regard to those woods referred to as being tried by Mr. Worthington Smith, he remarks in his report that any of them would be useful for some classes of work, if they could be imported, prepared, and sold for a farthing, or less than a halfpenny, per square inch. Specimens of all the woods here enumerated are contained in the Kew Museum. * * * * * COMPOSITE PORTRAITS.