electrolysis is generated in the form of nascent oxygen, which is far more active than ordinary oxygen. A molecule of the ordinary gas contains two elementary atoms, which work upon each other; with the electrolytic generation, however, a single atom is sent off, and this is chemically very active. It is sometimes called ozone; but chemists say that a molecule of ozone contains three atoms. Now, there is no known method of chemically manufacturing ozone in large quantities, and ordinary oxygen does not produce the required effect.
Again, Planté's supposition, that the charging current produced these two gases only, is incorrect. The sulphuric acid in the water, which he supposed only assisted in the conduction, really acts upon the lead in forming lead sulphate. This has its use in preventing the charged battery from running down when not in use, and from too rapidly expending itself when put to use.
A more perfect system of storage batteries is much to be desired. Already electricity is a staple article, and has a market price of so many cents per ampère-hour. But its sale is of necessity confined to limited areas. As soon as these can be extended, by means of storage, an improvement in our commercial welfare will become apparent, and the fear arising from the predicted loss of our coal-supplies, will not trouble the minds of our immediate posterity.
| ELEMENTARY BOTANY IN GENERAL EDUCATION.[1] |
By Prof. MARSHALL WARD.
AS I understand it, we may regard the study of botany as approachable from three points of view. We may speak of three ends to be attained: those of (1) elementary botany as a school-subject of general education; (2) advanced botany, as a subject of university or academic training, with a view to teaching and research; (3) special botany, for various purposes in after-life—e. g., those of foresters, planters, agriculturists, horticulturists, brewers, medical men, timber merchants, etc.
This is, of course, a merely aribitrary division for the argument, and not a philosophical classification of the subject-matter of the science of botany.
The next point is the scope of the teaching in each case. I should advocate that all children pass through the preliminary training embraced under No. 1 . Not only so, but I would urge the usefulness and importance of elementary botany in schools quite apart from its possible pursuit afterward.
- ↑ From a discussion at the Leeds Meeting of the British Association for the Advancement of Science, reported at length in Nature for October 23, 1890.
