Properly-constructed and serviceable blinds are expensive, and exterior contrivances of this kind are of little value unless they can be secured from damage from wind, etc. The old practice of whitewashing a roof is useful, but it has a glaring and ghastly appearance under bright sunlight; and it is in violent contrast with the foliage about it. For something like 150 superficial feet of glass a good mixture can be made of lb. of Brunswick Green and 3 lb. of size; the latter should be boiled in order to melt it, then the two should be mixed together, and diluted when wanted. If this be laid on carefully in spring, it will last all through the summer. It is particularly recommended for a cool-house, or for a fernery. - D. in London Garden.