Proceedings of the American Academy of Arts and Sciences, Volume 25Metcalf and Company, 1890 Vol. 12 (from May 1876 to May 1877) includes: Researches in telephony / by A. Graham Bell. |
Other editions - View all
Common terms and phrases
acuminate acute air-dried salt gave air-dried salt lost alcohol antheridia apex apothecia apothecium arise asci ascogonium basal cells base BaSO4 Batrachospermum benzol Boston bracts branches bromdinitroresorcine bromine Calculated calyx Cambridge CARBON coil Collema color condenser copper cortex crystals dense described diameter diaphragm diethylether distilled electrical electrode experiments filaments flowers frond genera genus glabrous gonidia grams H₂O heat hyaline hydrobromic acid hymenium hypha hyphæ inches long Induced Current inner lanceolate later layer leaves Lemanea less lichens lines long lobes magnetic malonic ester Maria Mitchell mass melting point nearly observed obtained obtuse ovate paper paraffine paraphyses pedicels perithecium petioles polypide pressure Professor pseudoparaphyses pubescent ramelli receptacle salt dried screw sepals sessile slender slightly sodic ethylate soluble solution species specimens spermogonia spermogonium Strength of Field substance gave sulphide sulphuric acid surface thallus tion tissue tribromdinitrobenzol trichogyne tube Tuomeya
Popular passages
Page 306 - Newton discovered, as a fundamental law of nature, that every particle attracts every other particle with a force which varies directly as the product of the masses and inversely as the square of the distance between them.
Page 348 - And indeed when we consider heat not as a substance, but as a state of vibration, there appears to be no reason why it should not be induced by an action of a simply mechanical character, such, for instance, as is presented in the revolution of a coil of wire before the poles of a permanent magnet.
Page 326 - College we had a telescope but not an Observatory. At Williamstown an Observatory had been constructed, but it was used for instruction, not for original work. At Washington Lieutenant Gilliss, and at Dorchester Mr. Bond, were commissioned by the government in 1838 to observe moon culminations in correspondence with the observers in the Wilkes exploring expedition for determining their longitude. These two prospective sets of observations, both of them under government auspices and pay, were the...
Page 348 - That the quantity of heat produced by the friction of bodies, whether solid or liquid, is always proportional to the quantity of force expended.
Page 326 - ... Georgetown Observatory building had been erected. Professor Loomis's work at Hudson should be measured by what others were doing at the time, rather than by the larger performance of to-day. In the summer of 1844, the year in which Professor Loomis came to New York, a new method in Astronomy had its first beginnings. The telegraph line had just been built between Baltimore and Washington, and Captain Wilkes at Baltimore compared his chronometer by telegraph with one at Washington, and so determined...
Page 70 - ... the anvil electrode was too small to be observed. Under these circumstances the observed motion of the hammer electrode, as measured by the micrometer, was the motion of this relatively to the anvil electrode, which is of course the quantity to be determined rather than the actual excursion of the hammer electrode. The microphone was placed in circuit with a battery and the primary of an induction coil, whose secondary contained a receiving telephone. With this arrangement the effect on the ear...
Page 238 - ACADEMY sary, on account of the self-induction of the measuring circuit, always to read either on opening or on closing the key. In our experiments the latter alternative was chosen. The results were plotted as previously by using the relative strength of the field as expressed by tangents of the magnetometer deflections as ordinates, and the induced currents in terms of an arbitrary unit as abscissas. The deflection of the ballistic galvanometer used was proportional to the strength of the transient...
Page 326 - ... that the exact determination of the longitude of a single point in the western country had a higher value then than it can have now, and that it could be obtained only by slow and tedious methods. These were, moreover, days of small things in astronomy in this country. At Yale College we had a telescope but not an observatory. At Williamstown an observatory had been constructed, but it was used for instruction, not for original work. At "Washington Lieutenant Gilliss, and at Dorchester Mr. Bond,...
Page 102 - ... thick. Clearly, this admits of further reduction. It is also feasible to decrease the strength of the steel tube, making the apparatus more delicate. 16. A second point of view is obtained by comparing the data of the pressure " on " and the pressure " off " phases of the above experiments. For convenience, I have constructed the results of Table I. in the chart, Figure 6. The degree of accordance in the "on...
Page 328 - ... Bay Company in the regions to the north of us, and finally a thorough discussion of the observations collected. A siege of three years was contemplated. In the history of the several steps that finally led to the establishment of the United States Signal Service, this report has an important place. The scheme laid down by Professor Loomis was in part followed out by the Institution. But the fragmentary character of the observations, the want of systematic distribution of the places of the observers,...