Popular Science Monthly/Volume 10/February 1877/Popular Miscellany
Talking by Telegraph.—On Sunday, November 26th, Prof. A. Graham Bell experimented with the "telephone" on the wires of the Eastern Railroad Company between Boston and Salem. Prof. Bell was assisted at the Boston end of the line by two operators, and Mr. Thomas A. Watson by one operator at the Salem end. According to the account published in the Commonwealth of Boston, conversation was carried on with Mr. Watson at Salem, by all those present, in turn, without any difficulty, even the voices of the speakers being easily recognized. Whispering was found to be perfectly audible, but was unintelligible. After a time, instead of grounding the wire at Salem, it was connected with North Conway, a distance of one hundred and forty-three miles from Boston, thus leaving Salem as a way-station. After this change had been made there was a slight diminution in the loudness of the tones, but no difficulty was experienced in carrying on conversation. Another change was made, whereby the electrical current was sent to Portland and back by another line to Salem, thus making Salem a terminal station at the end of nearly two hundred miles of wire. The result of this change was, that the tones of the speakers could be heard, but so faintly as to be unintelligible. With electro-magnets of a higher resistance, Prof. Bell is confident that the sounds would have been perfectly intelligible, the magnets used, it must be recollected, being only intended for a twenty-mile circuit.
How to reach the Pole.—Captain H. W. Howgate, of the Signal-Office, sees no grounds of discouragement in the failure of Nares's expedition to reach the north pole. The seasons, he remarks, vary in the arctic circle as markedly as in more temperate latitudes, and in a favorable year the ice of the so-called "Palæocrystic Sea" might be broken up. Captain Howgate would have a party of at least twenty hardy, resolute, and experienced men, with provisions for three years, stationed at some point near the borders of the Polar Sea—for instance, where the Discovery wintered last year. These men would seize the occasion of the opening of the frozen sea to push on to the pole. At the end of three years the party should be visited, and, if unsuccessful in accomplishing the object, should be revictualed and again left to their work. With a good, substantial building, such as could easily be carried on shipboard, they would be as comfortable and safe from atmospheric danger as the men of the Signal Service on the summit of Mount Washington. "A good supply of medicine," adds Captain Howgate, "a skillful surgeon, and such fresh provision as could be found by hunting-parties, would enable them to keep off scurvy, and to maintain as good a sanitary condition as the inhabitants of Godhaven in Greenland. Game was found in fair quantities by the Polaris party on the Greenland coast, and by those from the Alert and Discovery on the mainland to the west, especially in the vicinity of the last-named vessel, where fifty-four musk-oxen were killed during the season, with quantities of other and smaller game. A seam of good coal was also found by the Discovery's party, which would render the question of fuel a light one, and thus remove one of the greatest difficulties hitherto found by arctic voyagers. Let an expedition be organized to start in the spring of 1877, and I firmly believe that by 1880 the geography of the polar circle would be definitely settled, and that without loss of life."
Classification of the Races of Man.—The distinguished Italian ethnologist, Prof. Mantegazza, of Florence, in his introduction to Enrico Giglioli's narrative of a voyage round the Globe in the corvette Magenta, learnedly discusses the question of the classification of the races of man. His principal conclusions are that—1. Man is one of the most cosmopolitan and most variable of animals, and hence presents an infinite variety of races, sub-races, and peoples. 2. The number of races is indefinite; many races are extinct, others are now forming, still others will yet be produced. 3. The farther back we go in history, the larger is the number of races and sub-races, for in early times men less frequently moved away from their native localities and were more isolated from one another than now. 4. At the top and at the bottom of the human genealogical tree the branches and twigs approach one another, so that the most highly-cultured and the least developed races come into mutual contact. The negro developed into a Kaffre approximates to the European, and the European, degraded by cretinism or by hunger, to the Australian or the negro. 5. In general the lowest races are black or dark brown, the middle races somewhat less dark-skinned, and the highest white or nearly so. 6. In classifying the races of man we must, as far as possible, omit the question of their origin, for the investigation of this origin is the most fruitful source of ethnological errors.
The American Geographical Society.—The American Geographical Society was formally installed in its new quarters, No. 11 West Twenty-ninth Street, New York, November 28th. For many years this Society had rooms in the Cooper Union Building, but from the beginning it has been the intention of the leading members to secure possession of a building large enough to receive their valuable collection and library. The new headquarters is a large four-story and basement brown-stone front house on Twenty-ninth Street, near Fifth Avenue. On the first floor is a spacious reception-room, extending the entire depth of the house; its walls are covered with maps and charts. One of the curiosities of this room is the large map of South America once used by Humboldt. On this floor is also the room of the president of the Society. The second floor is devoted to the library and the secretary's room. In the library are 20,000 volumes, classified according to countries. The third floor contains the collection of maps and atlases. On the fourth floor is the Council's room, and in the basement are the offices for the clerical force.
On the evening of November 29th a second reception was held by the Society, and a paper on a journey to the Spitzbergen Sea was read by A. H. v. d. Hoeck. The author took occasion to expatiate upon the value of arctic research, pointing out the important results thence to be derived for anthropology, zoölogy, geology and paleontology, physics, and meteorology. Manuel M. Pereira, minister resident of Costa Rica, read a short paper on the projected canal across the Isthmus of Darien.
Hygrometers.—An hygrometer is an instrument for measuring the moisture of the atmosphere. It is often useful for gauging the dryness of rooms. It may not be generally known how simply such an instrument may be constructed.
When water, by means of a moist rag (whose moisture may be kept up by contact with water in a saucer or teacup), is spread over the surface of the bulb of a thermometer, the mercury in the latter falls, generally several degrees. The reason is, that the water evaporates and cools the bulb. The evaporation which takes place is, of course, produced by the absorption of heat from surrounding objects, the bulb included. The thermometer is affected in proportion to the reduction of temperature caused by the evaporation. It is evident that just as much heat as is required to convert water into vapor, just so much cold (or deprivation of heat) will be required to convert the vapor back again into water. When vapor begins to condense into water the temperature is at what is called the dew-point. It is evident, therefore, that theoretically the dew-point is twice as far as the vapor-point below the normal temperature of the atmosphere. Experiments show that it is a little more; a constant quantity of 13° Fahr. having to be added for heat lost and dissipated in the process.
These facts may be exemplified as follows: Hang two thermometers in a room of equable temperature, and suspend a third in a tin or glass vessel containing some tepid water. Wet the bulb of thermometer No. 2 as suggested above, and the evaporation will show the vapor-point. Pour ice water gradually and slowly into the vessel containing No. 3, and mingle it well with the water already there until the whole becomes so cold that the exterior of the vessel begins to contract moisture. It is then at the dew-point, and the thermometer in the vessel will be found to have fallen twice as much as No. 2, and 13° more.
No. 2 is a perfect hygrometer, as it shows the relative dampness of the atmosphere. When the latter is very dry, as in a room warmed by a hot-air furnace, evaporation takes place rapidly, and a large quantity of heat is abstracted from the bulb. When moist, as during a shower, very little evaporation takes place, and there is but a slight fall of the hygrometer. When the atmosphere is too dry the lungs suffer. It is in a wholesome condition when the hygrometer does not fall more than 7° Fahr. below the normal temperature. A hot-air furnace often sends it down 10° or 12° below.
The Studies of an Engineer.—Prof. Reynolds, of Owens College, Manchester, in an address on "Engineering as a Profession," proposes the following course of preparation for the student who aims to be an engineer: Up to the age of sixteen or seventeen he should devote himself to acquiring a "general education." Then he enters on his special course. In this he must learn something of science and something of art; but his main object should be to learn how the one can be brought to bear upon the other. Mathematics and natural science are indispensable, but he must not expect to become a master of either. Only a comparatively small portion of these wide subjects can be usefully brought to bear on engineering, and to these he must restrict himself. The methods of applying these sciences to engineering problems constitute a large subject, and one that is necessary for him to study. Then there are those manual operations which are essential to bring his knowledge to a practical issue, and in which a long course of training is necessary to acquire the requisite skill, such as mechanical drawing, and the use of measuring and surveying instruments. To acquire a useful knowledge of these various branches will require three or at least two years. The student will then proceed with his practical training, which should include as great a range of work as possible. In this he will find the knowledge he has acquired of very great help; he will recognize much that he sees, and be able to judge of the most important things to which to direct his attention.
Absorption of Nitrogen by Plants.—The chemist Berthelot has submitted to the Paris Academy of Sciences the results of a new series of experiments which prove that, under the influence of atmospheric electricity, free nitrogen is absorbed by the proximate principles of plants. The apparatus used in these experiments consists of a system of tubes in which the organic substances come into contact either with pure nitrogen or with atmospheric air, the whole communicating with a source of electricity at a tension precisely the same as that of atmospheric electricity. Under these conditions pure nitrogen, or the nitrogen of the atmosphere, is invariably fixed by the organic matter employed, viz., wet filtering paper or a solution of dextrine. The amount of nitrogen that is thus fixed is considerable. Tims these experiments bring to light a natural cause, hitherto overlooked, in considering the question of the fixation of nitrogen by vegetable tissues. It is now demonstrated that this fixation is brought about by the incessant action of the electricity of the atmosphere.
Development of Electricity by Light.—To determine experimentally the action of light in the development of electricity, Hankel took two bright strips of copper, one of which he fixed in a porous clay cell by means of a cork stopper. The cell was filled with water, and placed in a larger glass vessel containing the same water, in which was immersed the other strip, so that one of its surfaces was turned toward the source of light. The two strips were connected with the wire of a galvanometer. The glass with its contents was now placed in a black case having a slide, by means of which direct sunlight or colored light could be admitted to the outer strip of copper. The results were as follows: On access of free sunlight the illuminated strip was negative to the one in darkness, but only moderately so; behind a red glass the action was extremely small; behind yellow, a little stronger; behind green and dark blue successively, still stronger; behind dark violet it became less again.
The copper strips were now oxidized by moderate heating, and the following results were obtained: In free sunlight the illuminated strip was strongly negative; on darkening again, the deflection gradually disappeared; behind red glass the action was less; behind light-yellow glass the plate was first positive, then negative; on darkening, it first became still more negative, and then the action disappeared; behind dark-green glass the behavior was similar, but the first positive deflection was less; behind bright-blue, dark-blue, and violet glass, the plate was equally negative.
Strongly oxidized copper strips were next tested. In free sunlight the illuminated strip was first strongly positive, then weakly negative; on darkening, it was first strongly negative, then the action ceased. Behind red glass the plate was pretty strongly positive, but the deflection of the needle soon fell off considerably; behind bright yellow glass the strip was very strongly positive, but very soon the action diminished; on darkening, a strong negative deflection occurred. Behind dark-green glass the plate was first weakly positive, and then negative; behind dark-blue glass the cop per was also negative, and this change was more considerable than with free sunlight; behind violet glass, the action was similar. The author describes also the behavior of copper in sulphate-of-copper solution, and the behavior of silver, tin, brass, zinc, platinum; which metals were examined in the same way.
American Vine-Stocks and the Phylloxera.—In a communication to the Paris Academy of Sciences, M. Boutin gives an account of researches made by him to ascertain the reason why some American vine stocks resist the attacks of the Phylloxera vastatrix, while others succumb. The author has discovered in the resistant stocks a certain resinoid principle in proportion about a third greater than that in which it occurs in American non-resistant stocks, and in about double the proportion found in French stocks. M. Boutin considers it essential for resistance that the resinoid principle should occur in the proportion of 8 per cent, for the entire root, and 14 to 15 per cent. in the bark alone. He says that the incision made by the insect, while producing nodosities in the root, is cicatrized by the exudation of the resinous product, and this prevents the escape or loss of the nutritive sap of the plant. In non-resistant stocks, on the other hand, there is no cicatrization, as the resinoid principle is not in sufficient quantity to produce this effect.
Naturalists' Report of the British Arctic Expedition.—The results obtained by the naturalists attached to the British North Polar Expedition may be briefly summed up as follows: The mammals found farthest north, on the shore of the great Polar Basin, were the arctic fox, wolf, ermine, polar hare, lemming, and musk-ox. Bird-life was present as far as the land extended, the outlying species being the snowy owl, snow bunting, and ptarmigan. Of fishes few marine species were procured, but an interesting small salmonoid was found in freshwater lakes up to about latitude 82° 35'. Insect-life was more abundant than could have been expected, and a goodly number of species were obtained. Over twenty species of phasnogamic plants were discovered between latitudes 82° and 83°, and the cryptogamic flora was of course much more varied and abundant. The whole west coast, of Smith's Sound, from Cape Isabella to Cape Union, was fully surveyed and mapped, and large collections made of both fossils and rock-specimens; while the sled-parties, which explored the shores of the Polar Basin both to east and west, brought back sufficient material to determine the geological character of the country. Silurian limestones, richly fossiliferous, were the prevailing rocks along Smith's Sound. From the shales and sandstones of this formation a beautiful series of leaf-impressions were collected, illustrating the characteristic flora of the epoch, and presenting a remarkable demonstration of the existence of a temperate climate within 500 miles of the present pole, at a comparatively recent geological time. Lastly, very interesting and suggestive observations were made on glaciation and on ice action in general.
The Berlin Gorilla.—At the recent meeting of the German Association of Naturalists, Dr. Hermes, as we are informed by Nature, described some interesting characteristics of the young gorilla in the Berlin Aquarium. He nods and claps his hands to visitors; wakes up like a man and stretches himself. His keeper must always be beside him and eat with him; he eats what his keeper eats; they share dinner and supper; the keeper must remain by him till he goes to sleep, his sleep lasting eight hours. His easy life has increased his weight in a few months from thirty-one to thirty-seven pounds. For some weeks he had inflammation of the lungs, when his old friend Dr. Falkenstein was fetched, who treated him with quinine and Ems-water, which made him better. When Dr. Hermes left the gorilla on the previous Sunday, the latter showed the doctor his tongue, clapped his hands, and squeezed the hand of the doctor as an indication, the latter believed, of his recovery. For Pungu, as the gorilla is called, a large plate-glass palace has been erected in the aquarium in connection with the palm-house.
Lightning in a Telegraph-Office.—A telegraph-operator, in an office on the Boston and Providence Railroad, was lately killed by lightning. This is said to be the only case on record of an operator killed by lightning while in the office. Remarking upon this casualty, the Telegraphic Journal says that, "so far from being a source of danger, the electric telegraph must be regarded rather as a cause of safety, as a network of lines spread over a country tends to prevent an accumulation of electricity at any particular point, by continually and silently discharging it to the earth. This is particularly the case in districts where every pole has an earth-wire fixed to it, running from the top to the bottom. That these wires effectually discharge a lightning-flash has been seen in cases where the wires have been terminated within a few inches of the top of the pole: a lightning-flash striking one of these destroyed the portion of pole above the wire, but at the point where the wire commenced all damage ceased."