scholarly journals VIII. Account of a series of observations, made in the summer of the year 1825, for the purpose of determining the difference of meridians of the Royal Observatories of Greenwich and Paris; drawn up by J. F. W. Herschel, Esq. M. A. Sec. R. S

1826 ◽  
Vol 116 ◽  
pp. 77-126 ◽  
Keyword(s):  
Principal Direction ◽  
Considerable Extent ◽  
The Other ◽  
Principal Point ◽  
Royal Observatory ◽  
The Difference ◽  
A Chain ◽  
A Charge ◽  
Made In ◽  
Valuable Point

Operations having been carried on to a considerable extent in France, and other countries on the continent, for the purpose of ascertaining differences of longitude by means of signals, simultaneously observed at different points along a chain of stations; and the Royal Observatory at Paris, in particular, having been connected in this manner with a number of the most important stations, it was considered desirable by the French government that the Royal Observatory at Greenwich should be included in the general design. The British Board of Longitude was accordingly invited to lend its co-operation towards carrying into effect a plan for that purpose; and the invitation being readily accepted on their part, I was deputed, in conjunction with Capt. Sabine, in the course of the last summer, to direct the practical details of the operation on the British side of the channel, and to make the necessary observations. Every facility was afforded us in making our dispositions, on the part of the different branches of His Majesty's government to which it was found necessary to apply. A detachment of artillery was placed, by his Grace the Duke of Wellington, Master General of the Ordnance, under the orders of Capt. Sabine. Horses, waggons, and men, were furnished for the conveyance of a tent, telescopes, rockets, and other apparatus; and four of the chronometers belonging to the Board of Admiralty were placed at our disposal. The rockets required for making the signals were furnished us from France. It would have been easy, doubtless, to have procured them from the Royal Arsenal at Woolwich; but on the representation of Colonel Bonne, to whom the principal direction of the operations in France was intrusted, it was thought more advisable to accept an offer made to us of any number which might be required, prepared at Paris expressly for similar operations, carrying a charge of 8 ounces of powder, the instantaneous explosion of which, at their greatest altitude, was to constitute the signals to be observed. Our previous arrangements being made, on the 7th of July I left London; and after visiting the station pitched upon at Wrotham, which was the same with that selected by Capt. Kater and Major Colby, as a principal point in their triangulation in 1822; and finding it possessed of every requisite qualification for the purpose of making the signals, from its commanding situation, being unquestionably the highest ground between Greenwich and the coast, proceeded to Fairlight Down, near Hastings, where I caused the very convenient observatory tent, belonging to the Board of Longitude, to be pitched immediately over the centre of the station of 1821, which was readily found from the effectual methods adopted by the gentlemen who conducted the trigonometrical operations in that year, for securing this valuable point. Here, on the 8th, I was joined by Capt. Sabine, who, it had been arranged, should proceed to the first observing station on the French side of the Channel, there to observe, in conjunction with Colonel Bonne, the signals made on the French coast, and those made at the station of Mont Javoult; which latter were to be observed immediately from the observatory at Paris; while, on the other hand, it was agreed that M. le Lieutenant Largeteau, of the French corps of geographical engineers, should attend at Fairlight, on the part of the French commission, and observe, conjointly with myself, the signals made at La Canche, the post on the opposite coast (elevated about 600 feet above the sea, being nearly the level of Fairlight Down) and also those to be fired from Wrotham Hill, which were expected to be immediately visible from a scaffold, raised for the purpose on the roof of the Royal Observatory of Greenwich. By this arrangement, and by immediate subsequent communication of the observations made at each station, it was considered that the advantage of two independent lines of connexion, a British and a French, would be secured between the two extreme stations; i. e. the two national observatories; every possibility of future misunderstanding obviated, and all inconvenience on either side, arising from delay, or miscarriage in the transmission of observations, be avoided.

scholarly journals XIX. On the difference of meridians of the Royal Observatories of Greenwich and Paris

1827 ◽  
Vol 117 ◽  
pp. 286-296 ◽  
Keyword(s):  
The Other ◽  
Detailed Account ◽  
Sidereal Time ◽  
Methods Of Calculation ◽  
Royal Observatory ◽  
The Difference ◽  
Made In

In the Philosophical Transactions for 1826, Part II. Mr. Herschel has given a detailed account of observations, which were made in the month of July, 1825, for the purpose of ascertaining the difference of the meridians of the Royal Observatories of Greenwich and Paris, with a computation of these observations, from which the most probable value of the difference of longitude appears to be 9 m 21 s. 6. But I have perceived that in the copy of the observations delivered to him from the Royal Observatory of Greenwich, an error of one second has been committed; as the true sidereal time of the observation made there on 21st July, ought to be 17 h 38 m 57·12 in place of 17 h 38 m 56 s. 10, set down in the Table p. 104, which he informs me was computed at the Observatory, and officially communicated to him from the Astronomer Royal. This error seems to have had its origin in the little Table at the bottom of page 103; for, on subtracting the error of the clock, 47 s. 37, from the time 18 h 8 m 30 s. 40, the true sidereal time is 18 h 7 m 43 s. 03, instead of 18 h 7 m 42 s. 03, there given. The error in the result of that day’s observations, arising from this cause, has been partly compensated by a mistake of three tenths of a second, which has occurred in calculating the combined observations of the same day, the gain of mean on sidereal time being stated to be — 4 s. 54 (pp. 120 and 122), in place of — 4 s. 24. On checking the other observations, a few trifling alterations appear to be necessary upon the Greenwich Table of sidereal time, from the data given along with it. These seem to be occasioned by different methods of calculation, and indeed are hardly worthy of notice. The French astronomers not having given the data on which the calculations of the sidereal times at Paris are founded, they are assumed to be correct.

scholarly journals XXIII.—On the Disruptive Discharge of Electricity: An Experimental Thesis for the Degree of Doctor of Science, Department A

1878 ◽  
Vol 28 (2) ◽  
pp. 633-671 ◽  
Author(s):  
Alexander Macfarlane
Keyword(s):  
Copper Wire ◽  
Late Summer ◽  
The Other ◽  
Straight Line ◽  
Summer Session ◽  
The Difference ◽  
A Chain ◽  
The One ◽  
Metallic Parts ◽  
The University

The experiments to which I shall refer were carried out in the physical laboratory of the University during the late summer session. I was ably assisted in conducting the experiments by three students of the laboratory,—Messrs H. A. Salvesen, G. M. Connor, and D. E. Stewart. The method which was used of measuring the difference of potential required to produce a disruptive discharge of electricity under given conditions, is that described in a paper communicated to the Royal Society of Edinburgh in 1876 in the names of Mr J. A. Paton, M. A., and myself, and was suggested to me by Professor Tait as a means of attacking the experimental problems mentioned below.The above sketch which I took of the apparatus in situ may facilitate tha description of the method. The receiver of an air-pump, having a rod capable of being moved air-tight up and down through the neck, was attached to one of the conductors of a Holtz machine in such a manner that the conductor of the machine and the rod formed one conducting system. Projecting from the bottom of the receiver was a short metallic rod, forming one conductor with the metallic parts of the air-pump, and by means of a chain with the uninsulated conductor of the Holtz machine. Brass balls and discs of various sizes were made to order, capable of being screwed on to the ends of the rods. On the table, and at a distance of about six feet from the receiver, was a stand supporting two insulated brass balls, the one fixed, the other having one degree of freedom, viz., of moving in a straight line in the plane of the table. The fixed insulated ball A was made one conductor with the insulated conductor of the Holtz and the rod of the receiver, by means of a copper wire insulated with gutta percha, having one end stuck firmly into a hole in the collar of the receiver, and having the other fitted in between the glass stem and the hollow in the ball, by which it fitted on to the stem tightly. A thin wire similarly fitted in between the ball B and its insulating stem connected the ball with the insulated half ring of a divided ring reflecting electrometer.

scholarly journals XXXIV. Observations on the transit of Ve­nus, June the 6th, 1761, made in Spital-Square; the longitude of which is 4' 11" west of the Royal Observatory at Green­wich, and the latitude 51° 31' 15" north

1761 ◽  
Vol 52 ◽  
pp. 182-183
Keyword(s):  
The Sun ◽  
Royal Observatory ◽  
The Mean ◽  
The Difference ◽  
Made In

Having measured the diameter of Venus, on the sun, three times, with the object-glass micrometer, the mean was found to be 58 seconds; and but 6/10 of a second, the difference of the extremes.

scholarly journals IX. Experiments to determine the difference in the number of vibrations made by an invariable pendulum in the Royal Observatory at Greenwich, and in the house in London in which Captain Kater’s experiments were made

1829 ◽  
Vol 119 ◽  
pp. 83-102 ◽  
Keyword(s):  
Royal Society ◽  
Knife Edge ◽  
Capillary Action ◽  
Royal Observatory ◽  
The Difference ◽  
Made In

These experiments were made in compliance with a wish of the Council of the Royal Society, expressed in the following minute, dated December 13th 1827: “That Captain Sabine be requested to ascertain the difference in the number of vibrations of a pendulum between Mr. Browne’s house in London and the Royal Observatory at Greenwich.” The invariable pendulum employed to accomplish the proposed object was of the usual materials and form, new for the occasion, and numbered 12. The thermometer was the same that I had used in my former pendulum experi­ments; its graduation is described in the volume containing the account of those experiments, pages 182—187. The ball of the thermometer was sus­pended at both stations midway between the knife edge and the centre of the weight of the pendulum. The height of the barometer in the observations at Greenwich was taken by the standard barometer of the Observatory, which is in a room on the same floor as the pendulum room: in those at London it was taken by Mr. Browne’s barometer placed in the room in which the observa­tions were made. Mr. Browne’s barometer being compared with the standard of the Greenwich observatory, by means of an intermediate portable barometer, was found to require a correction of + 0.066 to make it agree with the indications of the Greenwich standard corrected for capillary action. This correction is consequently applied.

scholarly journals Experiments for investigating the cause of the coloured concentric rings, discovered by Sir Isaac Newton , between two object-glasses laid upon one anther

1832 ◽  
Vol 1 ◽  
pp. 264-268
Keyword(s):  
Focal Length ◽  
Considerable Extent ◽  
The Other ◽  
Sir Isaac Newton ◽  
Isaac Newton ◽  
Series Of Experiments ◽  
Made In

The account, given by Sir Isaac Newton, of these coloured arcs, appeared to Dr. Herschel highly interesting, but he was not satisfied with the explanation of them. Sir Isaac Newton accounts for the production of the rings, by ascribing to the rays of light certain fits of easy transmission and alternate reflection; but this hypothesis seemed not easily to be reconciled with the minuteness and extreme velocity of the particles of light. With the view of inquiring further into the cause of these phenomena, Dr. Herschel, so long since as the year 1792, borrowed of this Society the two object-glasses of Huygens, one of 122, and the other of 170 feet focal length. Notwithstanding various interruptions, the series of experiments, made in the course of this time, has been carried to a considerable extent; and Dr. Herschel thinks the conclusions that may be drawn from them, sufficiently well supported to point out several modifications of light that have been totally overlooked, and others that have not been properly discriminated.

A short account of some observations made with chronometers, in two expeditions sent out by the admiralty, at the recommendation of the board of longitude, for ascertaining the longitude of Madeira and of Falmouth. In a letter to Thomas Young, M. D. For. Sec. R. S. and Secretary to the Board of Longitude. By Dr. John Lewis Tiarks

1833 ◽  
Vol 2 ◽  
pp. 219-220
Keyword(s):  
Great Britain ◽  
The Other ◽  
Short Account ◽  
Other Hand ◽  
Royal Observatory ◽  
The Difference

Dr. Tiarks was sent to Madeira in the year 1822 with 15 chronometers, of which the rates had principally been ascertained in the Royal Observatory of Greenwich; he touched at Falmouth both in going out and returning; and having again ascertained the rates of his time-keepers, he was thus enabled to obtain two distinct determinations of the longitude of Falmouth, which differed about four seconds of time from that which had been inferred from the Trigonometrical Survey of Great Britain. It became therefore desirable that some further operations should be undertaken for the removal or elucidation of this discordance; and the following year a similar method was adopted with 25 chronometers, for determining the difference of longitude between Falmouth and Dover; this latter station having been chosen as easy of access, and as being perfectly determined; and the computations were made by interpolation, without employing any other rates for the chronometers than those which were observed in the different trips while they were actually on board the ship; and latterly, when Dover Roads became unsafe, the operations were limited to the distance from Portsmouth to Falmouth: thus, between the months of July and September, the observations were made three times at Dover, four times at Falmouth, and three times at Portsmouth; and the comparison of their results affords a correction of five seconds of time for the difference of longitude of Dover and Falmouth, and of three for the difference of Falmouth and Portsmouth, agreeing completely with the error of four seconds, attributed from the observations of the preceding year to the difference of longitude of Falmouth and Greenwich. Hence Dr. Tiarks thinks it fair to conclude that the diameter of the parallel circle, in which the longitude is measured, has in the survey been taken somewhat too great, and consequently the earth’s ellipticity greater than the truth. He remarks that the measurement of the spheroidal triangle concerned, determines only the actual flatness of the part of the earth’s surface on which it is situated, and not the actual magnitude of the whole parallel, unless its curvature be supposed perfectly uniform, which we cannot assume with confidence; while on the other hand, if we compute the ellipticity from the result of the chronometrical determination, it becomes one 314th instead of one 150th, and agrees with the most accurate measurements obtained from different principles. The longitude of Falmouth is finally determined to be 20 m 11 s. 1 of time, and that of the British Consul’s garden at Funchal, 1 h 7 m 39 s W. of Greenwich.

scholarly journals Propagation of Selected Pear and Quince Rootstocks By Hardwood Cuttings

2016 ◽  
Vol 64 (4) ◽  
pp. 1211-1217 ◽  
Author(s):  
Tomáš Nečas ◽  
Luděk Laňar ◽  
Ivo Ondrášek ◽  
Jan Náměstek ◽  
Jakub Láčík ◽  
...  
Keyword(s):  
Ethanol Solution ◽  
The Other ◽  
Naphthalene Acetic Acid ◽  
Rooted Cuttings ◽  
Beneficial Effects ◽  
Heat Stimulation ◽  
Other Hand ◽  
Heat Treated ◽  
The Difference ◽  
Made In

As long as new rootstocks continue to be developed, there will always the need for new genotypes to be controlled and evaluated. This study involves verification of selected rootstocks with reference to growth, propagation ability and other characteristics. Different rootstocks, different growth stimulators and different kinds of cuttings techniques were adopted for these experiments. Stimulators used for evaluations included: 1 % Racine (2.5 % naphthalene acetic acid - NAA), 0.5 % Rhizopon AA (2.5 % indole-3-butyric acid - IBA) and 0.25 % IBA in 50 % ethanol solution. There were three sets of experiments in all. In Experiment 1, the bases of cuttings were treated with the stimulators and part of them was also treated with heat before planting. Results from Experiment 1 indicated that cuttings treated with Rhizopon AA produced the best effect after heat treatment (with an overall average of 36.9 % of rooted cuttings). Pyrodwarf (78.7 %), Cydomalus (73.9 %) and Pyroplus (60.6 %) were the best performing rootstocks among the evaluated ones. In Experiment 2, we evaluated the influence of the date of harvesting the cuttings on rooting (comparisons were made between cuttings prepared in December [early] and March [late]). For BA29 rootstock cuttings, the best performance was attained by cuttings taken in March. The difference in rooting between March and December was 43.9 %. On the other hand, early harvested rootstocks (cuttings taken in December) for Cydomalus showed the best performance, with an 18.7 % difference between cuttings made in December and in March. Results from other evaluated rootstocks were not significant enough. In Experiment 3, the effect of chemical (phytohormone) stimulation and heat stimulations was compared. The best result was obtained by combinations of treatments without heat stimulations, when the cuttings were stored at 5°C and later treated with 0.25 % IBA in 50 % ethanol solution. The least rooting results, on the other hand, were observed in heat treated cuttings, in cuttings stimulated with IBA and subsequently with heat and in cuttings treated with a 3 cm radial cut at the base. Based on our findings we cannot prove clearly that heat stimulation and the phytohormones used have beneficial effects on rooting of especially new rootstock genotypes with an unknown propagation coefficient. This means that propagation using cuttings still remains an interesting topic to be further researched.

scholarly journals On the relation of hydrogen to palladium

1869 ◽  
Vol 17 ◽  
pp. 212-220 ◽  
Keyword(s):  
Hydrogen Gas ◽  
The Other ◽  
Linear Dimensions ◽  
Hydrogen Bubbles ◽  
Before And After ◽  
The Wire ◽  
The Difference ◽  
The One ◽  
A Charge ◽  
The Mind

It has often been maintained on chemical grounds that hydrogen gas is the vapour of a highly volatile metal. The idea forces itself upon the mind that palladium with its occluded hydrogen is simply an alloy of this volatile metal, in which the volatility of the one element is restrained by its union with the other, and which owes its metallic aspect equally to both constituents. How far such a view is borne out by the properties of the compound substance in question will appear by the following examination of the properties of what, assuming its metallic character, would have to be named Hydrogenium . 1. Density .—The density of palladium when charged with eight or nine hundred times its volume of hydrogen gas is perceptibly lowered; but the change cannot be measured accurately by the ordinary method of immersion in water, owing to a continuous evolution of minute hydrogen bubbles which appears to be determined by contact with the liquid. However, the linear dimensions of the charged palladium are altered so considerably that the difference admits of easy measurement, and furnishes the required density by calculation. Palladium in the form of wire is readily charged with hydrogen by evolving that gas upon the surface of the metal in a galvanometer containing dilute sulphuric acid as usual. The length of the wire before and after a charge is found by stretching it on both occasions by the same moderate weight, such as will not produce permanent distention, over the surface of a flat graduated measure. The measure was graduated to hundredths of an inch, and by means of a vernier, the divisions could be read to thousandths. The distance between two fine cross lines marked upon the surface of the wire near each of its extremities was observed.

A method for observing the eclipses of the moon, free from the common inconveniencies, as it was left by the learned Mr. Rook, late Gresham-Professor of Geometry

1665 ◽  
Vol 1 (22) ◽  
pp. 388-390
Keyword(s):  
The Other ◽  
The Moon ◽  
The Common ◽  
The Difference ◽  
Made In

Eclipses of the moon are observed for two principal ends; one astronomical, that by comparing observations with calculations, the Theory of the moons motion may be perfected, and the tables thereof reformed: the other, geographical, that by comparing among themselves the observations of the same ecliptick phases, made in divers places, the difference of meridians or longitudes of those places may be discerned.

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