The Galaxy, May, 1877 Part 24

SCIENTIFIC MISCELLANY.

THE TELEPHONE.

Great interest in telegraphic subjects has lately been aroused in the American public by exhibitions of the telephone, an instrument for transmitting sound vibrations by electricity. Two general forms of this instrument are known, in one of which a series of tuning forks communicates with a precisely similar series at the other end of the wire, and the signals made to one are repeated by the other. A more interesting form, and the one that has lately attracted so much attention, is that which receives and transmits ordinary vocal sounds.

The operator talks to a membrane, and at the other end of the wire is a resonator of some kind which talks to the auditor there. The fundamental idea of the machine is not new. It was at first proposed to use it for transmitting electric signals without a wire, and in that view a trial was made with it during the siege of Paris. The armistice interrupted the operations, but M. Bourbouze, the experimenter, and other inventors have continued to study the subject, Mr. A. G. Bell, professor of vocal physiology in Boston, being among them. M. Bourbouze used a vibrating needle the movements of which were effected by sound waves, and another Frenchman, M. Reuss, introduced the sounding box with its membrane. This is a box with a membrane stretched over the top and a short tube of large diameter in the side. The operator talks to this tube, and the box strengthens the sound, which finally affects the membrane, causing it to vibrate. Resting upon this membrane is a thin copper disc attached to a wire leading from the electrical battery. Above and very near it hangs a metallic point, which forms the end of a wire leading to the place to which the message is to be sent. The membrane rises slightly with every vibration, and touching the point, a current is established and communication effected with the distant point; but this communication ceases as soon as the vibration stops, and the membrane a.s.sumes a state of rest. As every simple note is produced by a definite number of air vibrations, and every compound sound is made up of the sum of several simple notes, the apparatus transmits a definite number of vibrations for each sound which it receives; and if those vibrations can be communicated to the air at any point, however distant, the original sounds will be reproduced. In short, the instrument may be explained as one invented to transmit air vibrations by electricity.

The receiver consists of an iron rod about the size of a knitting needle, wound with insulated copper wire, and supported on a wood box having very thin sides. The rod vibrates with every pa.s.sage of the current, and the thin box increases the amount of these vibrations and makes them audible. It is found best to introduce several rods into the insulated coil, as with only one the sound produced is rather snuffling.

In either case, however, the vibrations of the rod are exactly the same as those of the membrane, and even the character of the sound is automatically reproduced.

The description here given is that of Reuss's instrument, which was ill.u.s.trated last year in the French paper "La Nature." The exact construction of Mr. Bell's telephone has not been made public, but it seems to be quite similar. He is said to make his vibrating membrane of metal. The greatest distance to which sounds have been sent is one hundred and forty-three miles, from Boston to North Conway, N.H. The instrument is not yet perfect, the sounds being frequently indistinct.

With a private wire and two persons accustomed to each other's voices it would probably be a greater success. It is therefore likely to be quickly introduced into business uses. At present some rather wild antic.i.p.ations are indulged in by the daily press, but the instrument probably has a really remarkable future before it.

DAMAGES BY AN INSECT.

Traffic on railways and ca.n.a.ls has diminished, public taxes do not pay for collection, and poverty, privation, and misery have come upon twenty-five departments of France from the ravages of the phylloxera insect which attacks the roots of the grapevines. Such is the official report of a committee appointed by the Academy of Sciences. The important districts of Champagne, Burgundy, the Loire, and the Cher, are now threatened, and from the greatly extended foothold which the insect has now gained it is feared that its operations will be very rapid. It is not impossible that the princ.i.p.al industry of France will be crippled for years. In spite of all this, wine is now quite cheap. The hard times have lessened consumption, and the product is so huge--900,000,000 litres, or 180,000,000 gallons yearly from France alone--that the stock in the market is maintained in spite of the great ravages of the insect.

The cheapest claret is sold in New York for $40 a cask, or about 66 cents a gallon. Of this 24 cents is for duty.

THE SUMMER SCIENTIFIC SCHOOLS.

Summer schools of science proved very popular last year, and are to be continued this season. A lady who studied in the botanical school at Harvard said that work began properly at nine o'clock and continued to twelve; but the pupils were so eager to reap all possible benefit from the six weeks' course, that some were in the laboratory by 7:30 in the morning. One lady made herself sick in a week by over study, and many others injured themselves by too close application. The Professor finally prohibited work out of the regular hours. The schools will be reopened July 6, and continue to August 17, the term being six weeks long; applications to be made by June 1. The courses will be five in number, as follows: General chemistry and qualitative a.n.a.lysis, under Mr. C. F. Mabery, to whom (at Cambridge) applications must be sent; fee, $25 and cost of supplies. Phaenogamic botany, by Prof. George L. Goodale; fee, $25. For lectures without laboratory practice the charge is $10.

Cryptogamic botany will be taught by Prof. W. G. Farlow; fee, $25.

Microscopes, etc., are provided by the university. Students in this course should have a previous knowledge of phaenogamic botany. In addition to laboratory practice excursions will be made and lectures given. Prof. Farlow's address is 6 Park Square, Boston.

Prof. N. S. Shaler and Mr. Wm. M. Davis, Jr., will give a course in geology, including instruction in Cambridge, and a trip through Ma.s.sachusetts to New York. The tuition fee is $50, and other costs _about_ $50 for board and lodging, and $25 for travelling expenses.

When the regular excursion is finished a more extended trip will be made if desired, to the Mammoth Cave and other localities, on the way to Nashville, where the American a.s.sociation will have its next meeting.

Lastly, the school provides a course on zoology, by Mr. W. Faxon and Mr.

W. K. Brooks; fee, $25. It will comprise lectures, laboratory work, and excursions to the neighboring seash.o.r.es. Apply to Mr. W. Faxon, Cambridge, Ma.s.sachusetts.

_The Cornell Excursion._

Cornell university also has its summer school of natural history, and it will take a peculiar form this year. Prof. Theodore B. Comstock proposes, if sufficient encouragement is given before May 1, to charter a steamer and spend six weeks on the great lakes. The cheapness of steamer travel makes a trip of this kind in very comfortable style possible at moderate expense. The price is fixed at $125, which includes tuition fee and every other expense, for thirty days; and $3.50 per day for ten days more. The time may be extended beyond forty days by a majority vote of the excursionists. Buffalo or Cleveland will be the starting point, and the line of travel will be around the south sh.o.r.e of the lakes Erie, Huron, and Superior, returning by the north sh.o.r.e. The steamer will be a free rover, and visit places outside of the usual lines of travel. Lectures will be given and dredging done, the results of which will be distributed among the pupils, and shares may also be subscribed for by schools, teachers, and others. These shares will ent.i.tle the holders to part of the botanical and zoological collections made.

_Williams Rocky Mountain Excursion._

A more private but very extended excursion will be made by Williams college students, under the care of Prof. Sanborn Tenney, who holds the chair of natural history in the college. No fees are charged, and Prof.

Tenney receives no compensation. The number of students is limited to fifteen, who will for the most part pay their own expenses, and the expedition is not open to the public. The students are selected with reference to the study of geology and mineralogy, botany, and the various departments of zoology, entomology, ornithology, ichthyology.

Extensive collections will be made in all departments of natural history, which will be deposited in the Williams college natural history museum and the lyceum of natural history in the college. The excursion will start early in July and return in time for the regular autumn college opening. This is evidently intended to be one of the most important enterprises of the year for field instruction.

_A Texas Trip._

Butler college, Irvington, Indiana, will send an expedition to Texas, with headquarters at Dallas in that State. Studies in geology and natural history will be mainly pursued, and collections made of birds, fishes, reptiles, insects, plants, and fossils. The number of students will be from ten to twenty-five, and they will leave Indianapolis June 20, under the charge of Prof. John A. Myers. Mammoth Cave, Lookout mountain, and other places of interest in Tennessee and Alabama, will be visited, and the party will return in time for the a.s.sociation for the Advancement of Science meeting at Nashville. Dallas, which is to be the centre of operations, is a thriving town in the grazing region of Texas, and is a good place for the study of botany and zoology.

Another lake excursion is projected by the Inst.i.tute of Mining Engineers, who expect to spend two weeks in visiting the famous mining districts of that region. Though not precisely a "summer school," this will be both a professional and social excursion.

A committee of Wisconsin teachers recommend the introduction of this system of summer schools in that State. They want to have a cla.s.s formed under Prof. T. C. Chamberlin, State geologist, to commence at St. Croix Falls, and make geological, zoological, and botanical studies down the Mississippi to Rock Island. Headquarters would be on a large boat.

Directors of other summer schools are requested to send notices of the work they are planning to do to the office of this magazine.

AN INTELLIGENT QUARANTINE.

The quarantine history of New York was quite remarkable in 1876. Yellow fever was epidemic at several ports along the Gulf and Atlantic coast, and no less than 363 vessels came into New York from those ports, ninety-nine of which had the disease on board, either during the voyage or in port. Under these circ.u.mstances, it may be supposed that the authorities were not disposed to encourage commerce between the city and the infected towns. Philadelphia and Baltimore adopted an interdiction of all trade with Savannah, as a precaution. But a bolder and wiser policy has gradually been introduced into the New York quarantine. Instead of being a loser by the yellow fever, that city was called upon to take the whole trade, and did so without hesitation, though the voyage from Charleston and some other ports occupied less time than the average incubation period of the disease, which might be introduced unnoticed into the city unless preventative measures were taken. Orders were given to receive no pa.s.sengers from the afflicted cities, so that the quarantine authorities had only the cargo and crew to deal with. The ship was thoroughly fumigated and the cargo discharged as rapidly as was consistent with safe supervision. This rapid discharge is advised because a ship's heated hold is just the place for the full development of the fomites. If the cargo does carry the germs of the disease, the worst thing that can be done is to leave it in the ship, which is then likely to become a pest-house. Prompt removal reduces the danger to a minimum. By this intelligent course New York was able to keep open her communication with Savannah in the height of the epidemic, and she was the only city on the Atlantic to do so. More cotton than ever came to her harbor. The hygienic results are noticeable. Although more than a thousand deaths occurred in Savannah, not one case of yellow fever reached the _city_ of New York by water.

Two or three cases of sickness from vessels occurred in that city and Brooklyn; but though these were said to be yellow fever, their subsequent history did not sustain the supposition. They were probably a form of malarial fever which so nearly resembles the more dreaded disease that time is required to distinguish between them. Two cases of real yellow fever reached the city by rail, but all others were stopped at quarantine, which contained patients from January to the latter part of October, excepting one month--May. In all, sixty were treated there, most of whom were supposed to have yellow fever; but of these only thirty-nine really had that disease, the remainder having the peculiar form of malarial fever before spoken of. These results sustain the intelligent action of the quarantine officers who have stripped off the terrors which once hung about the name quarantine, and still do in so many parts of the world and of our own country.

THE "GRa.s.sHOPPER COMMISSION."

The last Congress made an appropriation of $18,000 for an Entomological Commission, and for once the Government has made a perfectly satisfactory series of appointments. Prof. C. V. Riley, the distinguished and experienced State entomologist of Missouri, is the chief of the commission, while Prof. Cyrus Thomas, State Entomologist of Illinois, one of the most noted American authorities, and Dr. A. S.

Packard, author of several works on insect and other morphology, are its other members. They will have their headquarters at Dr. Hayden's office, in Washington, and also a Western office in St. Louis. In the division of work Prof. Riley takes the country east of the Rocky mountains and south of the forty-eighth parallel, Prof. Thomas has Minnesota, Nebraska, South Dakota, and East Wyoming, and Dr. Packard the remainder of the country west of these two areas. The object of the commission may be stated to be the discovery of the best means of lessening the ravages of insects upon American crops; but to learn this it will be necessary to study not only the life histories of the gra.s.shopper and Colorado beetle, but also their climatic and geographical relations. The damage done by insects probably amounts to some scores of millions yearly, and it has long been apparent that one of the next services demanded of scientific men would be efficient aid and direction in the warfare of man against his smallest foes in the animal world. In the early history of a country, it is possible to provide against these losses by cultivating an excess of land, but when population becomes concentrated it is necessary to avoid the loss. The destructiveness of insects has never attracted so much attention as within the last half century, which is also notable as a period of extraordinary increase in the population of the civilized portions of the world. Now that the welfare of a great empire has been seriously threatened by the operations of one insect, and several States in our own country have been so overrun with another insect that both the States concerned and the general Government have been compelled to modify their laws in order to afford relief to farmers, the important relation of insect to human life has become clear, and is receiving due attention.

SURVEYING PLANS FOR THE SEASON.

The work of the Government surveys will not be stopped by the unfortunate failure of Congress to pa.s.s an appropriation for the army.

Hayden's party Will be in field by the middle of May, and Wheeler will, no doubt, be equally prompt. The former will confine his work to the region north of the Pacific railroad and east of the Yellowstone Park.

The triangulating party, under Mr. A. D. Wilson, will survey a system of triangles, and locate the princ.i.p.al peaks. Mr. Henry Gannett will take charge of the topographical work in the western and Mr. G. B. Chittenden in the eastern half of the field. A fourth division, under Mr. G. R.

Bechler, will survey in the northern portion, near the Yellowstone Park.

Each of these divisions contains about ten thousand square miles, so that if the parties are able to complete their work, the ground covered will be quite large.

THE CAUSES OF VIOLENT DEATH.

The violent deaths in Great Britain in 1874 were no less than 17,920, the highest number ever registered. There were 18 executions and 1,592 suicides, so that 16,310 may be cla.s.sed as unexpected. Railways killed 1,249, horse conveyances 1,313, and it is noted that those modes of conveyance which are mostly peculiar to cities were not responsible for this great slaughter. Street, or so-called horse railroads, killed 62 persons, omnibuses 55, cabs 61, and carriages 82, and these numbers show how great is the skill and care exercised in the crowded streets of cities. The source of the remaining 1,053 deaths by horses is not given in our authority (a Scotch paper), but it is probable that exercise in the saddle had much to do with them. There were 942 deaths in coal mines, and 118 in copper, tin, iron, and other mines. Lightning killed 25, sunstroke 90, and cold 114. There were 461 persons poisoned, about one-third being suicides. The bite of a fox, of a rat, of a leech, the scratch of a cat, and the sting of a hornet each killed one person, and two were stung to death by wasps. Of other noteworthy causes of death, it is mentioned that a girl fourteen years old died in childbed.

A NEW INDUCTION COIL.

The largest induction coil ever made has lately been constructed for Mr.

Wm. Spottiswoode by Mr. Apps. It has two primaries, of which the one used for long sparks weighs sixty-seven pounds and is formed of a bundle of iron wires 44 inches long and 3.5625 inches in diameter. The wire is 0.032 inch in diameter. This primary has 660 yards of copper wire 0.096 inch in diameter, and wound in 1,344 turns in six layers. The spark obtained with this primary is remarkably long in proportion to the battery power used. With five Grove's quart cells the spark was 28 inches, with ten cells 35 inches, with thirty cells 37.5 inches and 42 inches, and it is thought that even better results could be obtained.

The insulation is so good that seventy cells have been used without injury. The condenser is smaller than usual, being of the size commonly used with a ten-inch coil. It has 126 sheets of tinfoil, 18 by 8-1/4 inches, separated by two sheets of varnished paper. The other primary is heavier than the above described, weighing 92 pounds. The secondary coil contains 280 miles of wire, in 341,850 turns. It is used for spectroscopes and for short sparks. The power of this instrument is really comparable to that of lightning. A block of flint gla.s.s three inches thick has been pierced with the 28-inch spark.