By Prof. J. H. MONTGOMERY.

The numberless uses for india-rubber in this century has made it an indispensable article of commerce and manufacture, consequently its production has become a great industry. Whether the known forests will continue to supply the demand for any considerable time is a practical question. Right here comes the intelligence, that the attention of the government in India has been called to a new source of this useful gum. This new plant which yields large quantities of pure caoutchouc is a native of Cochin China, and is common in Southern India. It belongs to the dog-bane family (the same family that yields strychnine), and is called Prameria Glandalifera. In lower China its liquid juice is used for medicine by the Anamites and Cambodians, and it also appears among the drugs of China.

The Norwegian, SchÜbeler, mentions some striking peculiarities of plants in high latitudes. He says that seeds produced in these regions are much larger and weigh more than those grown in more temperate climates. The leaves, also, of most plants are larger in the north than those of the same species farther south. Flowers which are white in warmer climates, become colored when they blossom in the north. All these differences he ascribes to the continued light of long days.

It is noted by naturalists that Arctic plants are destitute of odor as a rule; only a few having a faint scent.

It appears from an English paper that the secretary of the Royal Society transplanted sea-weed to earth that was kept constantly moist, and that the plants grew and flourished under what would seem to be very unnatural circumstances. This would be an experiment worth trying with our fresh water plants.

By placing the stems of freshly cut flowers in a liquid dye their petals may often be colored or changed in color. This will not always happen, however, as certain colors are not absorbed by flowers. These dyes do not in any way change or affect the perfume or freshness.

The time honored method of determining the age of trees by counting their concentric rings has received some very hard blows from recent observations made on the growth of trees. An article in the Popular Science Monthly, from the pen of A. L. Childs, M.D., gives some facts which show that these rings do not indicate the age of the tree, and shows what they do indicate. The following passages from the article will give the ground on which his deductions are based: “In June of 1871 I planted a quantity of seed as it ripened and fell from some red maple trees. In 1873 I transplanted some of the trees from these seeds, placing them on my city lots in Plattsmouth, Nebraska. In August, 1882, finding them too much crowded, I cut some out, and, the concentric rings being very distinct, I counted them. From the day of planting the seed to the day of cutting the trees was two months over eleven years. On one, more distinctly marked (although there was but little difference between them), I counted on one side of the heart forty rings. Other sides were not so distinct; but in no part were there fewer than thirty-five. * * * * Hence, from my own record, I knew the tree had but twelve years of growth; and yet, as counted by myself and many others, it had forty clear concentric rings. * * * Hon. R. W. Furness, late Governor of Nebraska, so well known as a practical forester, has kindly furnished me with several sections of trees of known age, from which I select the following: A pig-hickory eleven years old, with sixteen distinct rings; a green ash eight years old, with eleven very plain rings; a Kentucky coffee-tree ten years old, with fourteen very distinct rings, and, in addition to these, twenty-one sub-rings; a burr-oak ten years old, with twenty-four equally distinct rings; a black walnut five years old, with twelve rings. * * * In conclusion, that the more distinct concentric rings of a tree approximate, or in some cases exactly agree, in number with the years of the tree, no one, I presume, will deny; but that in most, and probably nearly all trees, intermediate rings or sub-rings, generally less conspicuous, yet often more distinct than the annual rings, exist is equally certain; and I think the foregoing evidence is sufficient to induce those who prefer truth to error to examine the facts of the case. These sub-rings or additional rings are easily accounted for by sudden and more or less frequent changes of weather, and requisite conditions of growth—each check tending to solidify the newly-deposited cambium, or forming layer; and, as long intervals occur of extreme drought or cold, or other unfavorable causes, the condensation produces a more pronounced and distinct ring than the annual one.”