Page:The museum, (Jackson, Marget Talbot, 1917).djvu/142

116 to worms, and narrow strips of wood are glued onto the back running in the same direction as the grain of the wood. In these strips, which are usually about three-quarters of an inch wide and about two inches apart, grooves are cut at intervals of two inches and through these grooves are run strips of wood of the same width as the first and at right angles to them. These second strips must always be loose; the idea being that if the wooden framework on the back is too rigid, the picture will spread all the more, but where the framework gives as the wood in front moves, there is less danger. This process has been perfected by a number of high-class restorers and has now gained favor almost everywhere. There are still, however, a few men who feel that the only way to treat a wooden picture is to hold it absolutely rigid by the use of iron bars. These iron bars are screwed and clamped onto the wood in such a way that the picture is much more prone to crack than it was before. Over these irons a thck cement supposed to be waterproof is sometimes applied with the intention of keeping all air and moisture from the wood.

The method for the transfer of frescoes to canvas is an exceedingly interesting one and very difficult to perform. It is always a question how much one is going to get in removing a fresco