Of late, a theory has been propounded, in certain quarters, that blight in the pear-tree is caused by disease at the root of the tree. If this is founded in truth it would be well to make the following experiment. A few years after planting the young tree (or tree already planted), let there be planted within a foot or so of it two or three seedling pear-trees; and after these have become established (in a year or two), let them be inarched into the main tree. This would give three or four different systems of roots to the same tree, and perhaps would increase the chances of escaping blight as three or four to one, since if one system of roots suffers injury, the others might keep up a healthy vitality. The superior hardiness of such a tree would prove the theory, although the want of benefit might not disprove it. Let amateurs who love to experiment, and who know how to do such things, try it. W. L. D.

[We have little respect for this theory, although it is true that the root being hidden from our view we have no true opportunity for examining. There can be no objection to the test our correspondent suggests, provided any one is disposed to try it; but we think the components and condition of the soil would act alike on all the added plants or roots].

Hot - Air Furnaces are now in general use for heating dwellings both in city and country, and have almost superseded stoves in dwellings of any pretension. The objections hitherto made are now almost completely obviated; and this to a greater extent in the Gothic Furnace manufactured by A. M. Lesley, 605 Sixth Avenue, New York. We have in use one of these heaters in our dwelling, and it gives us pleasure to state that it is entirely free from escape of gas, economical in the consumption of fuel, free from complication, and supplies abundant heat.