Page:Popular Science Monthly Volume 31.djvu/445

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uralized themselves in Europe, and are becoming troublesome. All weeds are capable of being made useful as manure by plowing them in while they are green and before they have seeded.



A new feature in the summer courses in chemistry at the Harvard University Laboratory this year, will be a course comprising the work required in preparing for the admission examination in chemistry for the freshman class at Harvard College. It is based on Professor Cooke's recent pamphlet, and is offered to students and to teachers in preparatory schools. The usual courses in general chemistry, qualitative and quantitative analysis, and organic chemistry, will be given, and possibly a course in mineralogy. The courses will be under the direction of Arthur M. Comey, Ph.D., and will open July 11th and close August 20th. A course in practical botany, designed specially for teachers, will be given at the Harvard Botanical Garden, from July 6th to August 6th, under the direction of Professor Goodale. Further particulars will be furnished by the assistant in botany, Mr. J. E. Humphrey, No. 6 Divinity Hall, Cambridge, Massachusetts. All these courses are open to women. The total number of students in the chemical courses last summer was forty-three, and in the botanical course thirty-three.

M. Chevreul, one hundred years and eight months old, presented to the French Academy of Sciences, on the 9th of May, a memoir by M. Arnaud, recording the constant presence of the red-coloring alkaloid, carotine, in the leaves of all plants. The illustrious "dean of the students," whom M. Stanislas Meunier does not recollect to have ever seen "more alert, more enthusiastic in the exposition of natural truths, or more youthful in action," insisted on the precise character of the paper, and emphasized the association of chlorophyl with this substance of complementary color to its own. At the end he promised to revert to the subject and to discuss some other points in a future memoir.

It seems probable that for any further increase of speed in steam-vessels we must rely upon the engineer rather than upon the naval architect. The lines upon which our fastest ships are built can hardly be improved upon; but in the matter of power there is still an enormous waste. It is estimated that only one half of the total power exerted by the engines is effective in propelling the vessel. In addition to this, a very considerable portion of the heat-energy of the fuel escapes through the funnel instead of producing steam. Attention is now given to economizing in these matters as well as in the space allotted to engines, boilers, and fuel. The separation of freight from passenger traffic, after the system pursued on railroads, is destined to be an important factor in facilitating the construction of passenger-vessels of increased speed.

According to Dr. Charles H. Burnett, of Philadelphia, the use of properly constructed ear-trumpets improves the hearing permanently as well as aids it for the time. The cause of deafness being usually anchylosis produced by a catarrhal thickening of the mucous membrane of the auditory parts, passive motion overcomes the immobility that has been induced in them. The form of passive motion which acts most naturally here is that of sound. This form of passive motion, augmented as it is by means of the ear-trnmpet, acting frequently and systematically upon the ear, prevents further anchylosis, and the fatty degeneration of the auditory nerve that comes from desuetude. This, of course, tends to a permanent improvement of the hearing, and in some cases patients come to hear without the trumpet.

Preparations for the New York meeting of the American Association, to begin August 10th, are being carried vigorously forward. The President of the Local Committee of Arrangements is Dr. F. A. P. Barnard, the local treasurer is General Thomas L. James, and the local secretary is Professor H. L. Fairchild, Columbia College, New York. The Vice-Presidents are Chauncey M. Depew, Mayor Abram S. Hewitt, George William Curtis, Vice-Chancellor Henry M. MacCracken, Professor J. S. Newberry, Morris K. Jesup, and Judge Charles P. Daly. The whole committee numbers nearly five hundred. There is a large Ladies' Committee, of which Mrs. A. S. Hewitt is chairman, Mrs. Nicholas Fish, first member; Miss Winifred Edgerton, secretary; and Mrs. Sylvanus Reed, treasurer. The sessions of the Association will be held at Columbia College, where the rooms are ample for the several sections. A number of receptions and excursions have been spoken of already, but nothing definite can be said about these until the sub-committees report. The outlook is very promising, and the hope is indulged that the New York meeting will be the most successful in the history of the Association.

M. de Quatrefages and M. H. Chevalier have given their adhesion to the theory, which is taught, as to the Aryan race, in its earliest records, that the migrations of peoples in remote antiquity were provoked by the gradual increase of cold in the northern regions.