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574
THE POPULAR SCIENCE MONTHLY.

ever tends to obstruct transpiration promotes the accumulation of impurities. For this reason, even paint, though it may be intrinsically harmless, is objectionable. Paper is positively objectionable, because itself collects impurities and retains them; the substances with which it is prepared and decorated do the same; and the paste with which it is attached responds to all dampness and atmospheric influences, and readily becomes moldy. Kalsomine is faulty, because it is prepared with glue, and that, besides stopping the pores in the plastering (or "strangling the wall"), is liable to decay. No wall coating can be more healthful than a lime-wash. But, since that is inconvenient on account of its rubbing off, an excellent substitute is recommended by Mr. M. B. Church in calcined plaster of Paris, which hardens at once, forming a fixed shell of perfect porosity.

 


NOTES.

A Correction.—By a slip of the pen which also escaped notice in the proof-reading, Prof. Weismann is made to say twice in the second paragraph of page 357 of our July number "cerebellum" where "cerebrum" was intended. Read—"if, again, we were able to remove all the other parts of the cerebrum," etc., and "with the rest of the cerebrum was taken, etc."

The meeting of the British Association for 1890 will be held at Leeds, September 3d to 10th, under the presidency of Sir Frederick Abel. The sectional presidents will be: A, Dr. J. W. L. Glaisher; B, Prof. T. E. Thorpe; C, Prof. A. H. Green; D, Prof. A. Milnes Marshall; E, Sir R. Lambert Playfair; F, Prof. Alfred Marshall; G, Captain A. Noble; H, Dr. John Evans. Evening addresses will be given by Mr. E. B. Poulton on Mimicry; Prof. C. Vernon Boys on Quartz Fibers and their Applications; and Prof. Perry will lecture to the working classes on Spinning Tops.

A new food is described in the Kew Bulletin as used by the poorer classes in northern India. It is called phog, and is made from the flowers of the plant Calligonum polygonoides. They are eaten mixed with flour, or separately with salt and condiments They are rich in nitrogenous compounds, and somewhat resemble the seeds of the edible amaranths and buckwheats, only that in them sugar replaces starch.

A visible illustration of the figures produced by sound-waves has been devised by Mrs. Watts Hughes, in what she calls "voice-figures." They are practically Chladni's figures, produced in a viscid medium. Semi-fluid paste is spread over an elastic membrane stretched over the mouth of a receiver. A single note sung into the receiver throws the paste into waves and curves. The patterns formed are photographed immediately after production, or are transferred as water-color impressions while the membrane is still vibrating. Perhaps the most interesting figures are the "daisy forms," in which "the number of petals increases as the pitch of the note that produces them rises."

Mr. Albert Koebele, who was dispatched to Australia under the direction of the Entomologist of the Agricultural Department to obtain natural enemies of the "fluted scale" of the orange (Icerya purchasi), brought home an insect, the cardinal vedalia, which has proved very efficient. It has already multiplied to such an extent as to rid several groves from Icerya, and is looked upon as promising immunity in the near future for the entire State of California. In fact, Dr. Riley fears that it will do its work so well as to leave no field for other insects which Mr. Koebele procured, and which it is desirable to cultivate for the sake of having a variety.

In a paper in the Connecticut Pharmaceutical Association, Mr. D. G. Stoughton appears to have arrived, by a way of his own, at the conception of the identity of electricity with the other physical forces, heat and light, now demonstrated by Mr. Hertz's experiments. He regards them as resultants of the obstruction of ether motion by matter. Molecular motion, intense within the sun, is supposed to be transformed at the confines of the gaseous envelope surrounding that body into ether motion, which, passing through the ninety million miles of ether to the confines of our atmosphere, is obstructed by the molecules of atmosphere, and gives rise, according to the measure of the obstruction, to electricity, light, and heat.

Holmgren's test for color-blindness is the one recommended by those who have given the subject most attention. There are three parts to the test, which consist in picking out from a lot of wools all those skeins that match given ones in color. A pale green is the test-color first used, then a dilute purple, and finally a bright red. The person is not required to name any colors, as this is a different matter from distinguishing them.

A writer in Le Monde de la Science et de l'Industrie recommends, as an excellent insoluble plastic material, a mixture of cheese or casein or albumen and lime, well worked up. It is insoluble in hot water. Artistic effects may be obtained by molding, and it is easily colored.