suddenly disturbed. The hive was now placed on the hive-board, with the entrance toward the bees. For a little while they continued to run about, as if bewildered, but then was heard a peculiar vibrating and buzzing sound proceeding from the hive. In an instant all the bees faced about, with their heads toward the hive, and all marched into it in regular procession.
A New Respirator.—A new mask for filtering dust out of the atmosphere, and intended for use by workmen who follow sundry unhealthy trades, has been devised by Dr. B. W. Richardson. Having tried various substances in order to find a good filter, he gives the preference to feathers. The advantages of feathers as filters of dust are many: they are light, they separate perfectly, admitting air in any quantity while excluding dust, and they absorb water less perhaps than any other porous flexible substance. They have the further advantage of being cheap, and of being easily made up into filters. In constructing his mask he connects the light feathers drawn from the leg-plumage of the pheasant along a line of tape. This band he wraps around the perforated breathing-tube of the mask, so that the feathers fall over the perforations. In inspiration the feathers come down over the perforations, filtering the air as it enters, while in expiration they are blown out from the tube as feather-valves.
Bat-Guano.—In reply to a circular of inquiry addressed to numerous correspondents in the Southern States, Mr. McMurtrie, chemist to the United States Department of Agriculture, received a number of letters describing deposits of "bat-guano." Near Georgetown, Williamson County, Texas, there is a deposit supposed to amount to hundreds of tons, many apartments in the cave in which the excrement is found being filled to the mouth. Near Tuscumbia, Alabama, is a deposit estimated to be worth $20,000. A cave near San Antonio, Texas, is supposed to contain 15,000 or 20,000 tons of this guano, and the store is annually increasing. Samples from these and other deposits have been analyzed by Mr. McMurtrie. Most of them he found to contain both ammonia and nitrates. Under the microscope the material is seen to consist of the remains of the hard parts of insects in a finely-comminuted condition, which are the source of its nitrogenous constituents. As a fertilizer this guano compares favorably with the fish-products manufactured in New England, and even with Peruvian guano.
Prof. Marsh and his Paleontological Work.—Prof. O. C. Marsh, in a lecture to the graduating class of Yale College, summed up the main results of his paleontological researches in the Rocky Mountains. A syllabus of the lecture is published in the American Journal of Science. His conclusions as to the size and growth of the brain in mammals, from the beginning of the Tertiary to the present time, may be briefly stated thus: 1. All tertiary mammals had small brains. 2. There was a gradual increase in the size of the brain during this period. 3. This increase was mainly confined to the cerebral hemispheres. 4. In some groups the convolutions of the brain have gradually become more complicated. 5. In some the cerebellum and olfactory lobes have even diminished in size. There is some evidence that the same law of brain-growth holds good for birds and reptiles from the Cretaceous to the present time. Some additional conclusions in regard to American tertiary mammals as far as now known are as follows: 1. All the ungulata from the eocene and miocene had upper and lower incisors. 2. All eocene and miocene mammals had separate scaphoid and lunar bones. 3. All mammals from these formations had separate metapodial bones. At the conclusion of the lecture Prof. Marsh announced that his work in the field was essentially completed, and that all the fossil remains collected and in part described were now in the Yale College Museum. In future he should devote himself to their study and full description, and he hoped at no distant day to make public the complete results.
Seed-Production of the Sugar-Beet.—From experiments made by Corenwinder, it appears that when beet-roots are planted for the sake of seed, they, on first sprouting, part with a certain quantity of their