XIV. The Bakerian Lecture.—inquiries concerning the elementary laws of elec­tricity.—third series

1839 ◽  
Vol 129 ◽  
pp. 215-241 ◽  
Keyword(s):  
Royal Society ◽  
Quantitative Measurement ◽  
Electrical Measurement ◽  
Delicate Balance ◽  
Sources Of Error ◽  
Series Of Experiments ◽  
Many Sources ◽  
Electricity Intensity ◽  
Inductive Power

1. There is no department of science in which the perfection of quantitative measurement, and a clear perception of what we really measure, is more called for than in that of electricity. If we except the valuable researches of Professor Robison and of Coulombe, and the more recent investigations of Dr. Faraday, we can scarcely be said to possess, in common electricity at least, any connected series of experiments carrying with them a rigid numerical value. In the various inquiries into the ele­mentary laws of electricity, which I have had the honour of submitting to the con­sideration of the Royal Society, it has been my endeavour to perfect our methods of electrical measurement, whether relating to the quantity of electricity, intensity, inductive power, or other element requiring an exact numerical value, and, by operating with large statical forces both attractive and repulsive, to avoid many sources of error inseparable from the employment of very small quantities of elec­tricity, such as those affecting the delicate balance used by Coulombe. The instruments resorted to in these further inquiries have been employed with this view; they have been already described; I have only occasion to briefly mention some recent improvements in the hydrostatic electrometer mentioned in my first paper, and represented in Plate III. fig. 1.

scholarly journals Inquiries concerning the elementary laws of electricity

1843 ◽  
Vol 4 ◽  
pp. 156-157
Keyword(s):  
Electrical Measurement ◽  
The Other ◽  
Circular Disc ◽  
Attractive Force ◽  
Delicate Balance ◽  
The Subject ◽  
The One ◽  
Many Sources ◽  
Electricity Intensity ◽  
Direct Induction

The author states, that it has been his object, in this series of investigations, to perfect the methods of electrical measurement, whether relating to the quantity of electricity, intensity, inductive power, or any other element requiring an exact numerical value, and by operating with large statical forces both attractive and repulsive, to avoid many sources of error inseparable from the employment of extremely small quantities of electricity, such as those affecting the delicate balance used by Coulomb. He then describes some improvements in his hydrostatic electrometer, an instrument already mentioned in his first paper, which, although not available for the measurement of such minute forces as those to which the balance of torsion is applicable, is still peculiarly delicate and well adapted to researches in statical electricity. Its indications depending on the force between two opposed planes operating on each other under given conditions, are reducible to simple laws, and are hence invariable and certain; the attractive force between the discs is not subject to any oblique action, is referable to any given distance, and may be estimated in terms of a known standard of weight. The author next proceeds to the further consideration of the subject of his former papers, viz. the elementary laws of electrical action. He proves, by the following experiments, that induction invariably precedes, or at least accompanies attraction and repulsion. A circular disc of gilded wood, about six inches in diameter, is suspended by an insulating thread of varnished silk from a delicate balance; a delicate electroscope is attached to this disc, and the whole is counterpoised by a weight. A similar disc insulated on a glass rod, and having also an electroscope attached to it, is placed at any convenient distance immediately under the former. One of the lower discs being charged with either electricity and the other remaining insulated and neutral, the electroscope of the neutral disc begins to rise, whilst that of the charged disc, already in a state of divergence, tends to collapse: when these respective effects ensue, the suspended disc descends the charged disc. Two inductive actions are indicated in this experiment, the one the author considers to be a direct induction, the other a reflected induction.

scholarly journals XIV. On the absorption of gases by solids

1881 ◽  
Vol 32 (212-215) ◽  
pp. 407-408
Keyword(s):  
Royal Society ◽  
Hydraulic Press ◽  
Careful Examination ◽  
Solid Matter ◽  
Chemical Action ◽  
High Pressure And Temperature ◽  
Solid Iron ◽  
Series Of Experiments ◽  
The Subject ◽  
Very High

During the progress of the investigations which I have from time to time had the honour of bringing under the notice of the Royal Society, I have again and again noticed the apparent disappearance of gases inclosed in vessels of various materials when the disappearance could not be accounted for upon the assumption of ordinary leakage. After a careful examination of the subject I found that the solids absorbed or dissolved the gases, giving rise to a striking example of the fixation of a gas in a solid without chemical action. In carrying out that most troublesome investigation, the crystalline separation of carbon from its compounds, the tubes used for experiment have been in nine cases out of ten found to be empty on opening them, and in most cases a careful testing by hydraulic press showed no leakage. The gases seemed to go through the solid iron, although it was 2 inches thick. A series of experiments with various linings were tried. The tube was electro-plated with copper, silver, and gold, but with no greater success. Siliceous linings were tried fusible enamels and glass—but still the' tubes refused to hold the contents. Out of thirty-four experiments made since my last results were published, only four contained any liquid or condensed gaseous matter after the furnacing. I became convinced that the solid matter at the very high pressure and temperature used must be pervious to gases.

W. T. Astbury and Ross G. Harrison: the search for the molecular determination of form in the developing embryo

1980 ◽  
Vol 35 (2) ◽  
pp. 195-219 ◽  
Keyword(s):  
Royal Society ◽  
Limb Bud ◽  
Amphibian Embryo ◽  
X Ray ◽  
Biological Phenomena ◽  
Biology I ◽  
Series Of Experiments ◽  
Molecular Patterns ◽  
Molecular Determination

Amongst the Fellows elected to the Royal Society in 1941 were W. T. Astbury for his studies using X-ray analysis to study the structures of natural fibres, and amongst the Foreign Members elected that year was Ross G. Harrison for his contributions to embryology. Astbury and Harrison were very different in temperament, and worked in very different fields on either side of the Atlantic, yet they were united in their approach to the study of biological phenomena. Both Astbury and Harrison believed that the organization and form of biological materials whether wool fibres or the limb-bud in an amphibian embryo depended on molecular structure and pattern. Moreover both were concerned with dynamic aspects of form; Astbury’s greatest achievement was to demonstrate the dynamic, reversible folding and stretching of proteins in the k-m-e-f group, and Harrison looked to changing molecular patterns to account for changing symmetries in the developing embryo. It was this common approach that brought them together and led to Harrison spending a brief month in Leeds where they and K. M. Rudall performed what have been described as ‘truly progressive experiments in molecular biology’. I believe this short series of experiments illuminates the character and work of both Harrison and Astbury and illustrates the difficulties, practical and conceptual, in carrying out ‘progressive experiments’. I shall begin by reviewing briefly the embryological background of the time before going on to discuss in detail the approaches of Harrison and Astbury to their work and the outcome of their collaboration.

scholarly journals Phase Doppler quantification of agricultural spray compared with traditional sampling materials

2017 ◽  
Vol 70 ◽  
pp. 142-151
Author(s):  
R.L. Roten ◽  
S.L. Post ◽  
A. Werner ◽  
M. Safa ◽  
A.J. Hewitt
Keyword(s):  
Fluorescent Dyes ◽  
Droplet Velocity ◽  
Field Phase ◽  
Flux Data ◽  
Sources Of Error ◽  
Close Proximity ◽  
Flux Measurements ◽  
Many Sources

The quantification of spray mass has historically been accomplished by means of fluorescent dyes and various string and ground samplers to capture the dye-laden spray. However, these methods are typically not used in close proximity to orchard sprayers and are prone to many sources of error. The objective of this study was to assess the ability of an in-field phase Doppler (pD) interferometer to quantify spray mass against two common string samplers. Measurements were taken at 0.5 m increments to 4.5 m vertically and 1.0 m increments to 5.0 m downwind from the spray. Converted flux measurements from the strings were compared with those obtained using the pD interferometer. The current pD technology was found to be incapable of collecting equivalent flux data to that obtained from the strings. However, the pD equipment did provide useful data on droplet velocity and size.

scholarly journals Close-range radar rainfall estimation and error analysis

2016 ◽  
Vol 9 (8) ◽  
pp. 3837-3850 ◽  
Author(s):  
C. Z. van de Beek ◽  
H. Leijnse ◽  
P. Hazenberg ◽  
R. Uijlenhoet
Keyword(s):  
Positive Impact ◽  
Rain Gauge ◽  
Minor Role ◽  
Rainfall Estimation ◽  
Radar Rainfall ◽  
Sources Of Error ◽  
Ground Clutter ◽  
Received Power ◽  
Radar Calibration ◽  
Many Sources

Abstract. Quantitative precipitation estimation (QPE) using ground-based weather radar is affected by many sources of error. The most important of these are (1) radar calibration, (2) ground clutter, (3) wet-radome attenuation, (4) rain-induced attenuation, (5) vertical variability in rain drop size distribution (DSD), (6) non-uniform beam filling and (7) variations in DSD. This study presents an attempt to separate and quantify these sources of error in flat terrain very close to the radar (1–2 km), where (4), (5) and (6) only play a minor role. Other important errors exist, like beam blockage, WLAN interferences and hail contamination and are briefly mentioned, but not considered in the analysis. A 3-day rainfall event (25–27 August 2010) that produced more than 50 mm of precipitation in De Bilt, the Netherlands, is analyzed using radar, rain gauge and disdrometer data. Without any correction, it is found that the radar severely underestimates the total rain amount (by more than 50 %). The calibration of the radar receiver is operationally monitored by analyzing the received power from the sun. This turns out to cause a 1 dB underestimation. The operational clutter filter applied by KNMI is found to incorrectly identify precipitation as clutter, especially at near-zero Doppler velocities. An alternative simple clutter removal scheme using a clear sky clutter map improves the rainfall estimation slightly. To investigate the effect of wet-radome attenuation, stable returns from buildings close to the radar are analyzed. It is shown that this may have caused an underestimation of up to 4 dB. Finally, a disdrometer is used to derive event and intra-event specific Z–R relations due to variations in the observed DSDs. Such variations may result in errors when applying the operational Marshall–Palmer Z–R relation. Correcting for all of these effects has a large positive impact on the radar-derived precipitation estimates and yields a good match between radar QPE and gauge measurements, with a difference of 5–8 %. This shows the potential of radar as a tool for rainfall estimation, especially at close ranges, but also underlines the importance of applying radar correction methods as individual errors can have a large detrimental impact on the QPE performance of the radar.

scholarly journals II. On some phenomena exhibited by gun-cotton and gunpowder under special conditions of exposure to heat

1864 ◽  
Vol 13 ◽  
pp. 204-217
Keyword(s):  
Rapid Method ◽  
High Temperatures ◽  
Royal Society ◽  
Sufficient Accuracy ◽  
Hot Wire ◽  
Full Extent ◽  
Mechanical Condition ◽  
Series Of Experiments ◽  
The Wire ◽  
Made In

The experiments upon which I have been engaged for some time past, in connexion with the manufacture and properties of gun-cotton, have brought under my notice some interesting points in the behaviour of both gun. cotton and gunpowder, when exposed to high temperatures, under parti­cular conditions. I believe that these phenomena have not been previously observed, at any rate to their full extent, and I therefore venture to lay before the Royal Society a brief account of them. Being anxious to possess some rapid method of testing the uniformity of products obtained by carrying out General von Lenk’s system of manu­facture of gun-cotton, I instituted experiments for the purpose of ascer­taining whether, by igniting equal weights of gun-cotton of the same com­position, by voltaic agency, within a partially exhausted vessel connected with a barometric tube, I could rely upon obtaining a uniform depression of the mercurial column, in different experiments made in atmospheres of uniform rarefaction, and whether slight differences in the composition of the gun-cotton would be indicated, with sufficient accuracy, by a corre­sponding difference in the volume of gas disengaged, or in the depression of the mercury. I found that, provided the mechanical condition of the gun-cotton, and its position with reference to the source of heat, were in all instances the same, the indications furnished by these experiments were sufficiently accurate for practical purposes. Each experiment was made with fifteen grains of gun-cotton, which were wrapped compactly round the platinum wire; the apparatus was exhausted until the column of mercury was raised to a height varying from 29 inches to 29·5 inches. The flash which accompanied the deflagration of the gun-cotton was apparently similar to that observed upon its ignition in open air ; but it was noticed that an interval of time always occurred between the first application of heat (or incandescence of the wire) and the flashing of the gun-cotton, and that during this interval there was a very perceptible fall of the column of mercury. On several occasions, when the gun-cotton, in the form of “roving,” or loosely twisted strand, was only laid over the wire, so that it hung down on either side, the red-hot wire simply cut it into two pieces, which fell to the bottom of the exhausted vessel, without continuing to burn. As these results appeared to indicate that the effects of heat upon gun-cotton, in a highly rarefied atmosphere, differed importantly from those observed under ordinary circumstances, or in a very imperfect va­cuum, a series of experiments, under variously modified conditions, was instituted, of which the following are the most important.

Cadastral plotting by similarity transformation

CISM journal ◽  
1988 ◽  
Vol 42 (2) ◽  
pp. 121-125 ◽  
Author(s):  
Roy Gagnon
Keyword(s):  
Numerical Methods ◽  
Complex Number ◽  
Similarity Transformation ◽  
Cost Effective ◽  
Human Interface ◽  
Sources Of Error ◽  
Cadastral Maps ◽  
Numerical Transformation ◽  
Digital Methods ◽  
Many Sources

Cadastral maps generated from digitizing tabloids have too many sources of error to be reliable when plotted at large scales. To improve the 1:1000 cadastral map, three numerical methods were tested during twenty-seven mapping projects. The systems studied were: complex number similarity transformation, simultaneous similarity transformation, and iterative similarity transformation. There were several “human interface” difficulties with the computer routines but all of the programs were found to be reliable, and cost effective. All of the resulting cadastral maps are in daily use. Numerical transformation was found superior to digital methods of cadastral compilation.

scholarly journals University of Michigan Radiocarbon Dates XI

Radiocarbon ◽  
1966 ◽  
Vol 8 ◽  
pp. 256-285 ◽  
Author(s):  
H. R. Crane ◽  
James B. Griffin
Keyword(s):  
Standard Deviation ◽  
Half Life ◽  
Radiocarbon Dating ◽  
Geiger Counter ◽  
University Of Michigan ◽  
Radiocarbon Dates ◽  
Statistical Errors ◽  
Sources Of Error ◽  
The Many ◽  
Many Sources

The following is a list of dates obtained since the time of the compilation of List X in December 1964. The method is essentially the same as that used for the work described in the previous list. Two CO2-CS2Geiger counter systems are used. The equipment and counting techniques have been described elsewhere (Crane, 1961). The dates and estimates of error in this list follow the practice recommended by the International Radiocarbon Dating Conferences of 1962 and 1965, in that (a) dates are computed on the basis of the Libby half-life, 5570 yr, (b) A.D. 1950 is used as the zero of the age scale, and (c) the errors quoted are the standard deviations obtained from the numbers of counts only. In previous Michigan date lists up to and including VII we have quoted errors at least twice as great as the statistical errors of counting, in order to take account of other errors in the over-all process. If the reader wishes to obtain a standard deviation figure which will allow ample room for the many sources of error in the dating process, we suggest he double the figures that are given in this list.

II. Discussion of the results of some experiments with whirled anemometers

1881 ◽  
Vol 32 (212-215) ◽  
pp. 170-188
Keyword(s):  
Royal Society ◽  
Standard Pattern ◽  
Crystal Palace ◽  
Proper Factor ◽  
Series Of Experiments ◽  
The Government ◽  
Government Grant

In the course of the year 1872, Mr. R. H. Scott, F. R. S., suggested to the Meteorological Committee the desirability of carrying out a series of experiments on anemometers of different patterns. This suggestion was approved by the Committee, and in the course of same year a grant was obtained by Mr. Scott from the Government Grant administered by the Royal Society, for the purpose of defraying .the expenses of the investigation. The experiments were not, however, carried out by Mr. Scott himself, but were entrusted to Mr. Samuel Jeffery, then Superintendent of the Kew Observatory and Mr. G. M. Whipple, then First Assistant, the present Superintendent. The results have never hitherto been published, and I was not aware of their nature till on making a suggestion that an anemometer of the Kew standard pattern should be whirled in the open air, with a view of trying that mode of determining its proper factor, Mr Scott informed me of what had already been done, and wrote to Mr. Whipple requesting him to place in my hands the results of the most complete of the experiments, namely, those carried on at the Crystal Palace which I accordingly obtained from him. The progress of the enquiry may be gathered from the following extract from Mr. Scott's report in returning the unexpended balance of the grant.

XII. On the polarisation of light by oblique transmission through all bodies, whether crystallized or uncrystallized. By David Brewster, LL.D. F. R. S. Edin. and F. S. A. Edin. In a letter addressed to Taylor Combe, Esq. Sec. R. S

1814 ◽  
Vol 104 ◽  
pp. 219-230 ◽  
Keyword(s):  
General Result ◽  
Royal Society ◽  
Polarised Light ◽  
Partial Polarisation ◽  
Series Of Experiments ◽  
Humphry Davy ◽  
The Revolution

Sir, In a letter on “ the Affections of Light in its passage through crystallized Bodies," which I had the honour of transmitting a few days ago to the Royal Society through Sir HUMPHRY DAVY, I alluded to a series of experiments which I had in view for the purpose of generalising the various phenomena which had been described. At the very commencement of this enquiry I have been led to the important general result “ that “ light transmitted obliquely through all transparent bodies, “ whether crystallized or uncrystallized, suffers polarisation " like one of the pencils formed by doubly refracting crystals," and I hasten to communicate to you a brief sketch of the nature and consequences of this discovery. In examining if any change was produced upon common light during its passage along the oblique depolarising axis of mica, I observed, in one position of the mineral, some appearances which indicated a partial polarisation of the incident rays. Upon turning the mica round, so as to preserve its obliquity to the incident pencil, the same phenomena presented themselves in every part of the revolution of the mica, and the quantity of polarised light was found to increase with the obliquity of its incidence. I then substituted a plate of glass instead of the mica, and a similar result was obtained, though the quantity of polarised light was considerably less titan in the first experiment. By adding one plate of glass after another, the number of polarised rays was increased by the addition of each plate, and when the plates amounted to fifteen , the transmitted pencil was wholly polarised at an angle of about 70° 17', and possessed all the properties of that species of light.

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