Page:Popular Science Monthly Volume 6.djvu/779

Rh some of its latent heat; and it is precisely this disengaged heat which raises the temperature of the oxygen to such a degree that it begins to attack the tissues of the seed, and to awaken the life which lay dormant in it. The authors hold the mechanism of germination to be as follows: 1. Softening of the seed-envelopes by water; 2. Penetration of gases and disengagement of heat; 3. Alteration of the principles contained in the seeds by the heated oxygen. A memoir, giving full details on this subject, will shortly appear in the "French Annals of the Natural Sciences."

Marvine's Survey of Western Colorado.—From a letter of a New York Times correspondent, we take the following notes of the survey of Western Colorado, by Marvine's division of Hayden's exploring party: The most interesting section visited was the high mesa lying near the head of the White River. This mesa is nearly 1,000 miles in extent, and has an average altitude of about 12,000 feet. A large portion of it is a lava-bed, with innumerable lakes scattered over its whole extent. The influence of these lava-beds on the climate of this section is very marked. The party reached the mesa about the middle of September; it was almost enveloped in clouds; there were about four inches of snow, and the thermometer was down to 6°. The clouds lay on the mesa for weeks, though in the valley it was clear. On the east the mesa descends in precipitous slopes to the flats in Egeria Park; on the west the great lava plateau gradually falls and becomes well timbered, chiefly with spruce; the lava-top ceases, and is replaced by the sedimentary rocks rising from beneath it. The White River country, lying north of the mesa, constitutes the Ute Indian Reservation, and is described by Marvine's party as a grand hunting-ground, with game in abundance, plenty of water and timber, and large areas of fertile soil. It is the best portion of Colorado west of the Parks. The country in Egeria Park, east of the mesa, abounded in a great variety of beautiful wild-flowers, and raspberries of rich flavor. Mr. Barber, the botanist of the party, secured a large and rare collection. Toward the western limit of the region explored, excellent coal began to appear, with the promise of much beyond.

Voelcker on the Quality of Milk.—Dr. Voelcker, who holds high rank in England as an agricultural chemist, asserts that, owing to the natural variations in the quality of milk, it is utterly impossible, in all cases, to ascertain whether a small quantity of cream has been removed from milk, or an inconsiderable proportion pf water added to it. As the result of his own experience, he states that milk may be considered rich when it contains 12 per cent, of solid matter, of which 3 or 3$1/2$ are pure butter. If it contains over 12$1/2$ per cent, of solid matter, and has 4 per cent, or more of fat, it is of extra-rich quality. Good milk, of fair average quality, contains from 10$1/2$ to 11 per cent, of dry matter, including about 2$1/2$ per cent, of pure fat. Poor milk contains 90 per cent, or more of water. If milk is both skimmed and watered, it yields less than 4 per cent, of cream, and its specific gravity is about 1.025. A great many experiments have led the author to the conclusion that, within certain limits, the specific gravity is the most trustworthy indicator of quality. Some of the objections to the use of hydrometers are based on the mistaken opinion that cream is lighter than water. It is lighter than milk, but, compared with water, it is as 1.012, or even 1.019 to 1.000. A low specific gravity thus always indicates a large proportion of water. From sundry observations, it appears that good, pure milk has a specific gravity of 1.030, skimmed milk being a little lighter; and, further, that milk with a specific gravity below 1.025 is either mixed with water, or is naturally very poor. A useful instrument for approximately determining the percentage of cream is a graduated glass tube, at the top of which the cream may be allowed to collect, and its quantity may be read off.

The Royal Society of Great Britain.—The origin of the English Royal Society is related as follows in the "Memoirs of the French Academy." We give the passage as translated in Nature: "Full fifty years had elapsed (in 1666) since the learned men who lived in Paris began to meet at the