The Chateau of the duc de Luynes, the translator of the Meditations, was the home of a Cartesian club, that discussed the questions of automatism and of the composition of the sun from filings and parings, and rivalled Port Royal in its vivisections.
He discovered a fact subsequently rediscovered by others, that a tube of metallic filings, loosely packed, was sensitive to electric sparks made in its vicinity, its electrical resistance being reduced, and he was able to detect effects on such a tube connected to a battery and telephone at a distance of 500 yds.'
He constructed one form of his coherer of a glass tube a few inches long filled with iron borings or brass filings, having contact plates or pins at the end.
When such a tube is inserted in series with a single voltaic cell and galvanometer it is found that the resistance of the tube is nearly infinite, provided the filings are not too tightly squeezed.
In 1894 he exhibited apparatus of this kind in which the tapping back of the tube of filings was effected automatically.
The interspace is filled with a very small quantity of nickel and silver filings, about 95 per cent.
At the receiving station Marconi connected a single voltaic cell B 1 and a sensitive telegraphic relay R in series with his tube of metallic filings C, and interposed certain little coils called choking coils.
- Marconi Sensitive Metallic Filings Tube or Electric Wave Detector.
Lodge arranged a mechanical tapper for the purpose which continually administered the small blow to the tube sufficient to keep the filings in a sensitive condition.
Fleming 5 invented special forms of the metallic contact or metallic filings sensitive tube.
The secondary circuit of this transformer is cut in the middle and has a condenser inserted in it, and its ends are connected to the sensitive metallic filings tube or coherer as shown in fig.
If a magnet is dipped into a mass of iron filings and withdrawn, filings cling to certain parts of the stone in moss-like tufts, other parts remaining bare.
A sheet of cardboard is placed above the magnet, and some iron filings are sifted thinly and evenly over the surface: if the cardboard is gently tapped, the filings will arrange themselves in a series of curves, as shown in fig.
Ir`"' lines of force," of which the curves formed by the filings afford a rough indication; Faraday's lines are howeve confined to the plane of the cardboard, but occur in the whole of the space around the magnet.
A south pole would be urged oppositely to the conventional " direction " of the line; hence it follows that a very small magnetic needle, if placed in the field, would tend to set itself along or tangentially to the line of force passing through its centre, as may be approximately verified if the compass be placed among the filings on the cardboard.
Stannic Chloride, SnC1 4, named by Andreas Libavius in 1605 Spiritus argenti vivi sublimate from its preparation by distilling tin or its amalgam with corrosive sublimate, and afterwards termed Spiritus fumans Libavii, is obtained by passing dry chlorine over granulated tin contained in a retort; the tetrachloride distils over as a heavy liquid, from which the excess of chlorine is easily removed by shaking with a small quantity of tin filings and re-distilling.
Alloys of magnesium and silicon are prepared by heating fragments of magnesium with magnesium filings and potassium silico-fluoride.
For efficiency the operation must be conducted with small quantities; caking may be prevented by mixing the substance with sand or powdered pumice, or, better, with iron filings, which also renders the decomposition more regular by increasing the conductivity of the mass.
Chlorates); but it is manufactured by acting with bromine water on iron filings and decomposing the iron bromide thus formed with potassium carbonate.
By heating magnesium filings with methyl and ethyl iodides A.
Winkler discovered that an iron chain wound round the bottle could be substituted for the hand, and Sir William Watson in England shortly afterward showed that iron filings or mercury could replace the water within the jar.
It may be synthetically obtained by distilling oxindole (C 8 H 8 NO) with zinc dust; by heating orthonitrocinnamic acid with potash and iron filings; by the reduction of indigo blue; by the action of sodium ethylate on orthoaminochlorstyrene; by boiling aniline with dichloracetaldehyde; by the dry distillation of ortho-tolyloxamic acid; by heating aniline with dichioracetal; by distilling a mixture of calcium formate and calcium anilidoacetate; and by heating pyruvic acid phenyl hydrazone with anhydrous zinc chloride.
He discovered that heat is evolved when iron filings and sulphur are rubbed together to a paste with water, and the artificial volcan de Lemery was produced by burying underground a considerable quantity of this mixture, which he regarded as a potent agent in the causation of volcanic action.
An amorphous form results when a mixture of iron filings and sulphur are triturated with water.
Potassium ferric sulphide, K2Fe2S4, obtained by heating a mixture of iron filings, sulphur and potassium carbonate, forms purple glistening crystals, which burn when heated in air.
He discovered that they had the power of affecting the electric conductivity of materials when in a state of powder, the majority of metallic filings increasing in conductivity.
The ordinary forms of metallic filings coherer of the Branly type require tapping to bring them back to the high resistance or sensitive condition.
Boron hydride has probably never been isolated in the pure condition; on heating boron trioxide with magnesium filings, a magnesium boride Mg 3 B 2 is obtained, and if this be decomposed with dilute hydrochloric acid a very evil-smelling gas, consisting of a mixture of hydrogen and boron hydride, is obtained.