Page:Popular Science Monthly Volume 16.djvu/152

 becomes actually incorporated with its substance. After this burning process, it only remains for the different pieces to be united with the grooved leaden framework which binds the whole together. The places where the leads join are then carefully soldered together, and nothing remains but to thoroughly work over the whole surface with a thick kind of cement, which fills up any interstices between the glass and lead, and renders the whole panel perfectly watertight and weather-proof."

Assimilative Power of Plants.—In a paper read before the Dublin Royal Society, Dr. C. A. Cameron states the result of a preliminary experiment made by him to determine the possibility of substituting for some of the elements in plants other elements of the same atomicity. A sod was taken from a field in which a crop of the so-called artificial grasses (which are chiefly leguminous plants, and not grasses at all) was just peeping over ground. It was placed in a box, and one half of the plants were watered twice a week with a weak solution of potassium selenate. The total quantity of potassium selenate applied to the plants during four weeks amounted to twenty grammes. The result showed that selenic acid, at least when applied in small quantity, does not injure plants. Secondly, it was found that selenic acid had been absorbed by the plants. To determine this point, the plants were partially dried and boiled in strong nitric acid until thoroughly destroyed. The solution was evaporated to dryness, and the residue was treated with dilute hydrochloric acid, which dissolved it nearly completely. The solution was concentrated and raised with a saturated solution of sulphurous acid, whereupon the liquid assumed at once a deep, blood-red color, from the separation of selenium. The plants had been carefully washed before being dried. In concluding his paper, Dr. Cameron writes as follows: "I think this experiment proves that selenic acid is not injurious to plants when used in small quantity, and that the acid is taken up and retained by plants, or at least by certain varieties of plants. The experiment, however, did not prove whether or not there was a partial replacement of sulphur trioxide by selenium trioxide or of sulphur by selenium. Having lately become possessed of large quantities of selenium compounds, I propose to grow plants in soil or water free from sulphur in any form, but supplied with potassium and ammonia selenates. Should the results of this proposed experiment prove interesting, I shall do myself the honor of submitting them to the society."

Honey-making in the United States.—The annual production of honey in this country is estimated at about 35,000,000 pounds, and the business of bee-keeping is being rapidly systematized. One firm of wholesale grocers in New York keeps as many as 12,000 swarms; other keepers have often from 3,500 to 5,000 swarms. Arrangements are made with farmers and owners of orchards to allow an apiary of a certain number of swarms to be placed in their grounds. At the distance of three or four miles another apiary is placed with another farmer, and so on. For this accommodation the bee-keepers pay either in money or in shares. It is estimated that on an average an acre will support twenty-five swarms, yielding fifty pounds of honey each. The apiaries are cared for by men in the employ of the bee-owners. Many ingenious contrivances have been introduced for the purpose of saving the labor of the bees and the keepers. About ten years ago a German suggested that thin, corrugated sheets of wax, which he called "artificial tablets," should be provided for the bees to make their comb from. These, however, did not come into general use; but a few years ago Mr. W. M. Hoge effected an improvement by starting the side-walls of the cells. When these "foundations," as they are called, were presented to the bees, the intelligent little creatures at once took advantage of them, and extended the side-walls so as to form the regular hexagonal cell. The machine by which the impression is made on both sides of the wax is very simple, and somewhat resembles a clothes-wringing machine, only the iron rollers are studded with little hexagonal-headed pins just the size of the section of a cell, so that, when the thin sheet of wax is pressed up between the pegs to the height of about one sixteenth of an inch, it offers a substance for the construction of the cell-walls. Another remarkable adaptation of machinery is