can be laid down in regard to cases. Beyond these each museum will have to find out by experience what to do and what to avoid.
Some twenty years ago came the first agitation in favor of metal cases. The advocates of these contended that they were: 1. safer in case of fire, 2. more dust-proof, and 3. better adapted for showing objects because the frames were thinner and less conspicuous. The subject has caused much controversy, but the present opinion seems to be that so far as fire danger is concerned one type of exhibition case is as bad as another. A metal case is more expensive to build, but is also more permanently satisfactory in our changeable climate because not subject to the same contraction and expansion experienced by wood. On the other hand, the building of wooden cases has been affected by the design of the metal case and the wooden framework for the glass can now be made as light as is desired and as is proportioned to the size of the case. Cases as well as other museum equipment are now considered more beautiful and suitable if they are without ornament. The plainer and less conspicuous the lines of the case and the finer and quieter the grain of the wood and the finish, the better it fulfils its function in setting forth the objects within. In art museums to-day three types of cases are used,
