The physical properties of the two typcs of hydrogen are somewhat different, particularly their specific hcats. I t is assumed that the nuclei in the two atoms of a molecule of orthohydrogen are spinning in the same direction, while those of parahydrogcn are spinning in opposite directions.
Flant Growth Controlled by Chemical Adjustment. A plant's speed or slowness in producing flowers and seed depends on internal chemical adjustments, which in turn may be controlled by changing the conditions under which the plant grows, in the opinion of Prof. N. A. Maximov of the Institute of Applied Botany a t Leningrad, Russia. Prof. Maximov has lately duplicated by chemical manipulation the results obtained by himself with temperature control, and by the American workers, W. W. Gamer and H. A. Allard, in shifting the flowering and fruiting times of plants. I t is Prof. Maaimov's theory that there is in plants an antagonism between vegetative growth, producing stems and leaves, and reproductive growth, which results in flowers and fruits. What encourages one discourages the other. Some plants, moreover, have a tendency to run strongly t o vegetative growth, and only some kind of a physiological jolt will drive them into reproductive activity. This is the case, according to the Russian plant physiologist, with winter wheat, which is given its impulse to bear grain by the winter cold. The general condition which causes plants to vegetate instead of reproducing is a high carbohydrate ratio in their makeup; high nitrogen content drives them into hlwm. Prof. Maximov held natural early bloomers in the vegetative condition for a long period by cutting down their supply of nitrogen fertilizers, and he forced natural late bloomers into precocious flowering by giving them a superabundance of this element.-Srirnce .Service
Clay for Pencils. Bentonite. The d a y for pencil leads must be absolutely free from grit, and, to achieve this, long grinding or a costly refining by endosmotic means is necessary. I t is pointed out by the United States Bureau of Mines. Department of Commerce, that purified bentonites would probably be admirably suitable for the manufacture of pencil leads, and some of the large pencil companies are understood to be using this material already for indelible leads and crayon work, thus effecting a considerable saving in grinding cost. The use of some other wetting agent would eliminate the excessive drying shrinkage resulting from the use of watcr with alkali types. The manufacturers of indelible leads, crayons, pastel colors, and the like, where grease or wan is used in the mix, would, it is suggested, find bentonite of considerable value as a constituent of their products.-Chem. A @ , 20, 543 Uune 8, 1929). Production of Cadmium in U. S. The production of metallic cadmium in the United States in 1928 amounted t o 1,875,896 pounds, valued a t $1,114,297, This is an increase of 75 per cent in quantity over the production of 1,074,654 pounds in 1927. There were 233,101 pounds of cadmium, valued a t $128,901, imported into the United States during 1928, compared with 22,400 pounds, valued a t S13,172, in 1927. No imports of this metal we,-e recorded for 1'326. I n addition to metallic cadmium, domestic manufacturers reported some production of the following cadmium compounds in 1928: Cadmium sulfide, cadmium sulfate, cadmium hydrate, cadmium oxide, and cadmium lithopone. The estimated cadmium content of cadmium compounds produced was 240,000 pounds, valued a t $228,013, in 1928, compared with 229,000 pounds, valued a t 8191,051, in 1927.-Chem. Age
