scholarly journals II. On the solvent power of liquid cyanogen

1872 ◽  
Vol 20 (130-138) ◽  
pp. 67-70 ◽  
Keyword(s):  
Copper Wire ◽  
The Other ◽  
Boiling Water ◽  
Small Fragment ◽  
Gutta Percha ◽  
Solvent Power

In the following experiments a number of stout tubes of refractory glass of the annexed shape were employed. Each tube was closed at one end, and had a flanged mouth at the other. The limb A was 11/2 inch long, the limb B 2 inches, and C 7 inches. In making the experiments, each tube was first filled, to an extent of 51/2 inches of its length, with highly dried crystals of mercuric cyanide; a small fragment of asbestus* was then pushed tightly against the end of the cyanide by means of a thin rod of gutta percha, and the bend of the tube cleaned by means of a slender brush. A number of taper plugs of gutta percha were previously made by softening, the end of a rod of that substance in boiling water and then chilling it ; and loops of thin copper wire were also prepared for the purpose of securing the plugs.

scholarly journals III.—The Basalt of the Moabite Stone

1902 ◽  
Vol 9 (11) ◽  
pp. 493-495
Author(s):  
T. G. Bonney
Keyword(s):  
Constant Pressure ◽  
The Other ◽  
Small Fragment ◽  
Late Professor ◽  
Semitic Language ◽  
Louvre Museum

A block of basalt, bearing an ancient inscription in a Semitic language, was discovered in 1868 at Dhiban (the Dibon of Scripture) by the Rev. F. A. Klein, of the Jerusalem Mission Society. This block, which measured 3′ 10″ × 2′ 0″ × 1′ 2·5″, proved on examination to have been erected by Mesha, King of Moab about 890 b.c., and to refer to the war mentioned in 2 Kings iii. A series of blunders on the part of those anxious to obtain this interesting relic caused a quarrel about ownership between two Arab tribes, and one of them, to spite the other, broke it in pieces. These, however, were obtained by the French Consul in Palestine, and sent to Paris, where they were fitted together so far as possible, and the repaired stone is now in the Louvre Museum. The late Professor E. H. Palmer, on a visit to Dhiban in 1870, picked up a small fragment from those still lying on the spot, which he gave to me on his return to England. The constant pressure of other work has hitherto prevented me from examining the specimen, and I have only recently had a slice prepared. The largest face of the fragment measures about 3″ × 2·5″, but the thickest part hardly exceeds half an inch. The original smoothed surface of the stone, possibly including part of a letter, may be seen on one of the sloping sides.

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 "In vitro" evaluation of the apical sealing of root canals obturated with different techniques

2003 ◽  
Vol 11 (3) ◽  
pp. 181-185 ◽  
Author(s):  
Viviane Haiub Brosco ◽  
Norberti Bernardineli ◽  
Ivaldo Gomes de Moraes
Keyword(s):  
Continuous Wave ◽  
The Other ◽  
Blue Dye ◽  
Methylene Blue Dye ◽  
Root Canals ◽  
Gutta Percha ◽  
Sealing Ability ◽  
Better Than ◽  
Positive Controls

The purpose of this study was to compare the apical sealing of root canals obturated with different techniques. One hundred-six human mandibular incisors were submitted to instrumentation by means of the step-back technique. After instrumentation, one hundred teeth received an impermeable coating on the external surfaces of the crown and root (except for the area nearby the apical foramen). Afterwards, they were divided in five groups containing twenty elements each, according to the obturation technique employed: 1. lateral condensation with Kerr file; 2. continuous wave of condensation technique with System B; 3. thermoplasticized injectable gutta-percha technique with the Ultrafil system; 4. mechanically thermoplasticized gutta-percha with the JS Quick-Fill system and 5. thermoplasticized gutta-percha associated to a master cone with the Microseal system. The six remaining teeth were employed as negative and positive controls. After obturation, the access cavities were sealed and the teeth were immersed in aqueous 2% methylene blue dye for 72 hours at 37ºC. After that, the teeth were longitudinally sectioned and the apical microleakage was evaluated in a stereomicroscope. The Microseal system presented the best apical sealing ability, followed by System B, JS Quick-Fill, Ultrafil and the lateral condensation technique. The statistical analysis of the results demonstrated that: 1. the Microseal system presented an apical sealing similar to System B and better than the other groups; 2. System B presented better apical sealing than the lateral condensation technique, being similar to the other groups; and 3. the lateral condensation, Ultrafil and JS Quick-Fill groups demonstrated similar sealing ability.

scholarly journals Deux fragments de portraits funéraires romains de Deir el-Bahari

2011 ◽  
pp. 259-266
Author(s):  
Zsolt Kiss ◽  
Keyword(s):  
19Th Century ◽  
The Other ◽  
General Context ◽  
Small Fragment ◽  
Intermediate Period ◽  
The Third ◽  
The Temple ◽  
Third Intermediate Period

Two fragments of painted Roman funerary portraits on wooden panels of the Fayum type, discovered in 2001 during a revisiting of the Third Intermediate Period shaft tombs inside the Chapel of Hatshepsut in the Royal Mortuary Cult Complex at the Temple of Hatshepsut in Deir el-Bahari, come from 19th century excavations, hence are without anything but a general context. The pieces are very small—fragment of a robe, sliver of a face with one eye—but in a brilliant analysis of iconography and style Kiss identifies one as a depiction of a female, possibly a priestess of Isis, from the second half of the 2nd century AD, and the other as a male portrait from the 2nd century. The portraits may belong to what some scholars have called “Theban” painted funerary portraits and they must have come from a Roman necropolis in West Thebes, possibly Deir el-Medineh. On any case, they are proof that mummies with painted portraits of the deceased on wooden panels fitted into the cartonnages were not unknown in ancient Thebes.

scholarly journals On the magnetic power of soft iron

1837 ◽  
Vol 3 ◽  
pp. 187-188
Keyword(s):  
Electric Current ◽  
Copper Wire ◽  
Complete Removal ◽  
The Other ◽  
Present Communication ◽  
Hard Steel ◽  
Electric Current Passing ◽  
Good Contact ◽  
The One ◽  
Single Helix

When free magnetism is developed by induction, and is not retained in that state by what has been termed the coercive force of hard steel, it has generally been considered that all the phenomena due to the existence of free magnetism cease on the removal of the inducing cause. The object of the present communication is to show that such is not the fact. From a variety of experiments described by the author, it appears that soft iron continued to exhibit strongly the attraction due to the developement of magnetism long after the means by which the magnetism had been originally excited had ceased to act. In these experiments, bars of soft iron, in the form of a horseshoe, had a single helix of copper wire wound round them, so that on the ends of the wire being brought into contact with the poles of a voltaic battery, the iron became an electromagnet. With one of these horse-shoes, while the connexion between the ends of the helix and the poles of the battery existed, the soft iron, having a keeper applied to its poles, supported 125 pounds it supported 56 pounds after that connexion had been broken, and continued to retain the power of supporting the same weight after an interval of several days, care having been taken not to disturb, during the time, the contact between the horse-shoe and its keeper. On this contact, however, being broken, nearly the whole attractive power appeared to be immediately lost. The author describes several instances of the same kind, particularly one in which the contact between the ends of the horse-shoe of soft iron and its keeper having been undisturbed during fifteen weeks, the attractive power continued undiminished. Although the interposition of a substance, such as mica or paper, between the ends of the horse-shoe and its keeper necessarily diminished the force of attraction, it did not appear to diminish the power of retaining that force. In a case where the electromagnet of soft iron and its keeper were equal semi-circles, the author found, what may appear singular, that the arrangement of the magnetism during the time that the electric current traversed the helix, appeared not to be the same as after the cessation of that current; in the one case similar, and in the other dissimilar, poles being opposed to each other at the opposite extremities of the two semi-circles. Whether the magnetism was originally developed in the soft iron by means of an electric current passing round it, or by passing over its surface the poles of an electromagnet, or those of a common magnet of hard steel, it appeared to possess the same power of retaining a large portion of the magnetism thus developed. The retention of the magnetism does not appear to depend upon the relative positions of the ends of the horse-shoe and the keeper remaining undisturbed, but on their contact remaining unbroken: for one keeper was substituted for another without diminution of this power; care being taken that the second should be in good contact with both ends of the horse-shoe before the complete removal of the first.

1. On the Electrical Conductivity of Stretched Silver Wires

1878 ◽  
Vol 9 ◽  
pp. 79-85 ◽  
Author(s):  
J. G. MacGregor
Keyword(s):  
Electrical Conductivity ◽  
Copper Wire ◽  
Silver Wire ◽  
The Other ◽  
Brass Plate

The apparatus which I used in a few experiments on silver wires was as follows:—To a beam, supported in stonework, a plate of copper was fastened, upon which a smaller plate could be tightly screwed. Between the two plates a very thick copper wire was secured, vertically. Its lower end was provided with a small plate of copper, fastened by screws. This plate served to make fast one end of the silver wire under investigation. The other end was joined in the same way to a second thick copper wire; this was provided with a horizontal round brass plate, through the centre of which it passed, and which acted as weight-carrier.

scholarly journals IV. On the development of electric currents by magnetism and heat

1869 ◽  
Vol 17 ◽  
pp. 265-267
Keyword(s):  
Copper Wire ◽  
Glass Tube ◽  
Rubber Band ◽  
The Other ◽  
Internal Diameter ◽  
External Diameter ◽  
Thin Glass ◽  
Iron Wire ◽  
It Flexibility ◽  
Electric Current Passing

I have devised the following apparatus for demonstrating a relation of current electricity to magnetism and heat. A A, fig. 3, is a wooden base, upon which is supported, by four brass clamps, two, B, B, on each side, a coil of wire, C; the coil is 6 inches long, 1½ inch external diameter, and ⅜ of an inch internal diameter, lined with a thin glass tube; it consists of 18 layers, or about 3000 turns of insulated copper wire of 0·415 millim. diameter (or size No. 26 of ordinary wire-gauge); D is a permanent bar-magnet held in its place by the screws E, E, and having upon its poles two flat armatures of soft iron, F, F, placed edgewise. Within the axis of the coil is a straight wire of soft iron, G, one end of which is held fast by the pillar-screw H, and the other by the cylindrical binding-screw I; the latter screw has a hook, to which is attached a vulcanized india-rubber band, J, which is stretched and held secure by the hooked brass rod K and the pillar-screw L. The screw H is surmounted by a small mercury cup for making connexions with one pole of a voltaic battery, the other pole of the battery being secured to the pillar-screw M, which is also surmounted by a small mercury cup, and is connected with the cylindrical binding-screw I by a copper wire with a middle flattened portion O to impart to it flexibility. The two ends of the fine wire coil are soldered to two small binding-screws at the back; those screws are but partly shown in the sketch, and are for the purpose of connexion with a suitable galvanometer. The armatures F, F are grooved on their upper edges, and the iron wire lies in these grooves in contact with them; and to prevent the electric current passing through the magnet, a small piece of paper or other thin non-conductor is inserted between the magnet and one of the armatures. The battery employed consisted of six Grove’s elements (arranged in one series), with the immersed portion of platinum plates about 5 inches by 3 inches; it was sufficiently strong to heat an iron wire 1·03 millim. diameter and 20·5 centims. long to a low red heat.

scholarly journals Magnetic properties of supraconductors

1936 ◽  
Vol 154 (882) ◽  
pp. 378-385 ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
External Magnetic Field ◽  
Copper Wire ◽  
Thermal Contact ◽  
Threshold Value ◽  
Test Tube ◽  
The Other ◽  
Longitudinal Field ◽  
Thick Wire

Mendelssohn and Babbitt observed that the induction in solid and hollow tin spheres which became supraconductive in an external magnetic field did not fall quite to zero, but that part of the magnetic flux was “frozen in” at the threshold value. This behaviour could be explained by considerations based on the shape of the specimen, although it was not certain if this was the only reason for the effect. It seemed therefore that it would be of interest to investigate specimens of a shape which assured simpler conditions, such as long rods in a longitudinal field, in addition to extending the experiments to a greater number of supraconducting substances. Method The same two helium liquefiers with which the previous experiments were carried out were used again. The specimens employed were in the form of long rods attached by a short thick wire of electrolytic copper to the helium container. The wire was autogenously welded to one end of the specimen, the other end of the copper wire being soldered to the helium container. In the case of mercury the metal was contained in a test tube held independently, into which a copper wire dipped and made thermal contact. A coil one layer thick of 47 s. w. g. copper wire was wound round the middle of each specimen, the ends being connected to a ballastic galvanometer.

scholarly journals Experimental researches in electricity

1837 ◽  
Vol 3 ◽  
pp. 91-93
Keyword(s):  
Electric Current ◽  
Copper Wire ◽  
The Other ◽  
Great Length ◽  
Electrical Currents ◽  
Electric Current Passing ◽  
Electrical Condition ◽  
The Moment ◽  
Electrical Induction ◽  
Experimental Researches

This paper is divided into four parts: the first being on the Induction of Electric Currents; the second, on the Evolution of Electricity from Magnetism; the third, on a new Electrical Condition of Matter; and the fourth, on Arago’s Magnetic Phænomena. The author defines electrical induction to be the power which electrical currents possess of inducing any particular state upon matter in their immediate neighbourhood. A great length of copper wire, 1-20th of an inch in diameter, was wound round a cylinder of wood so as to compose two helices, the coils of which were intermixed, but prevented from touching each other by interposed threads of twine and calico. One helix was connected with a voltaic battery, and the other with a galvanometer. No effect was perceived on the latter, with a battery of 10 plates; a slight effect only with one of 100 plates; and a distinct deflection of the needle of the galvanometer occurred when the contact was made with a battery of 120 plates. While the contact was preserved, the needle returned to its natural position, and was unaffected by the electric current passing through the wire connected with the battery; but on breaking the connexion, the needle of the galvanometer was again deflected, but in a direction contrary to that of its former deflection. Hence it is inferred that the electric current sent by the battery through one wire, induced a similar current through the other wire, but only at the moment the contact was made; and a current in the contrary direction when the passage of the electricity was suddenly interrupted. These transitory currents, resembling waves, were found to be capable of magnetizing needles placed within the helix. Collateral currents, either in the same or in opposite directions, exert no permanent inductive power on each other.

scholarly journals IV. On a magneto-electric machine

1867 ◽  
Vol 15 ◽  
pp. 404-405
Keyword(s):  
Copper Wire ◽  
Electric Machine ◽  
The Other ◽  
Platinum Wire ◽  
External Work ◽  
Small Machine

In June 1864 I received from Mr. Wilde a small magneto-electric machine, consisting of a Siemens’s armature and six magnets. This I endeavoured to improve upon, my object being to get a cheap machine for blasting with Abel's fusees. This was done by making one of circular magnets, and a Siemens's armature revolving directly between the poles, the armature forming the circles; with this I could send a very considerable power into an electro-magnet, &c. It was then suggested to me by my assistant, that if the armature had two wires instead of one, the current from one being sent through a wire surrounding the magnets, their power would be augmented, and a considerable current might be obtained from the other wire available for external work; or there might be two armatures, one to exalt the power of the magnets, and the other made available for blasting other purposes. Want of time prevented me carrying this out until now; but since the interesting papers of C. W. Siemens, F. R. S., and Proissor Wheatstone, F. R. S., were read last month, I have carried out the idea as follows:— Two bars of soft iron, measuring 7½in. x 2½ in. x ½in., are each wound, round the centre portions, with about thirty yards of No. 10 copper wire; and shoes of soft iron are so attached at each end, that when the bars are placed one above the other there will be a space left between the opposite shoes in which a Siemens’s armature can rotate: on each of the armatures is wound about ten yards of No. 14 copper wire cotton covered. The current generated in one of the armatures is always in connexion with the electro-magnets; and the current from the second armature, being perfectly free, can be used for any purpose for which it may be required. The machine is altogether rudely constructed, and is only intended to illustrate the principle; but with this small machine three inches platinum wire ·01 can be made incandescent.

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