The 1827 Christmas Lectures
of Michael Faraday

Lecture #1

Substances -- Solids, Fluids, Gases and Chemical Affinity

Faraday's first lecture offers straightforward illustrations of chemical principles that help us understand many materials and events of daily experience.

He opens with examples of the properties of matter in general, carefully separating the specific behaviors of solids and fluids (Exp. 1-8). Conversion between solid and fluid is achieved by raising or lowering temperature (Exp. 9-12).

Faraday points out that it is easy to overlook gases, or if they are noticed, to assume they are immaterial. Special attention is therefore drawn first to gases in general (Exp. 13-16), then to a few gases with remarkable individual behavior (Exp. 17-21). Gases are created from the solid or fluid phase by heat, and are re-condensed by cooling (Exp. 22, 23).

Faraday next turns our attention to the attractions responsible for chemical action, demonstrating magnetic and static electrical attractions on objects large and small, taken two at a time and in large numbers (Exp. 24-26). These forces are most effective at close range. Indeed, however small the particles may be, if they are sufficiently close, they can easily exert attractive force strong enough to make them cling together tightly (Exp. 27-31). This explains the formation of solids or fluids from gases. Sample size does not affect overall physical properties or chemical activity (Exp. 32-34).

The chief hallmark of a chemical reaction is the production of new materials with properties quite different from the old, even though some effects of the change may be transient (Exp. 35-37). Different chemical reactions create and consume solids, fluids, and gases in all conceivable combinations (Exp. 38-47) . They can produce or remove any chemical property, such as acidity or alkalinity (Exp. 48-53). It is even possible by a sequence of reactions to have a compound first disappear then reappear (Exp. 54, 55). Whole classes of substances, such as metals, can actually be ranked according to their ability to react under analogous conditions (Exp. 56-60). Many ways are available to accelerate sluggish reactions or to retard vigorous ones (Exp. 61-86).

In the first of Michael Faraday's Christmas Lectures in 1827, he presented 86 experiments or demonstrations. The following is a list of these experiments as he labeled them, followed by a brief explanation of what we believe that he did.

[STATES OF MATTER]

Exp. 1: Solid Matter, its resistance

Pieces of marble, tin and wood were used to show that solids cannot be penetrated.

Exp. 2: Solid Matter, weight

Lead, wax, etc., and a balance were used to show that equal volumes of different solids do not always have the same weight.

Exp. 3: Solid Matter, retention of form

Crystals and clay were used to show that most solids hold their shape.

Exp. 4: Fluids, weight

Faraday gives no description of what he did here. It is assumed that he used a balance and several fluids to show that equal volumes of different fluids do not necessarily have the same weight.

Exp. 5: Fluids, resistance

A glass syringe was filled with water to show that fluids can not be compressed easily.

Exp. 6: Fluids, resistance

A cork was put in a dish of mercury to show that the solid was able to penetrate the liquid (or that the liquid had less resistance than the solid); however, the liquid did not penetrate the solid.

Exp. 7: Fluids, resistance

A water hammer (a small amount of water in an evacuated tube) was used to show the resistance of the solid as the liquid falls freely and hits it.

Exp. 8: Fluids, no retention of form

Mercury was poured from a glass to a basin to show that fluids do not maintain the same form or shape at all times.

Exp. 9: Change of solid into fluid by heat

a log of spermaceti (whale oil) was melted, then cooled.

Exp. 10: Change of solid into fluid by heat

water, frozen in a tube, was melted. It was pointed out that the only difference between winter and summer water was the physical state.

Exp. 11: Fusible metal

Wood's Metal will melt at a temperature below 212 oF. It is made by combining 2 parts bismuth, 1 part lead, and 1 part tin.

W. A. Miller, Elements of Chemistry, John Wiley & Sons Publishers, New York, 1868, p. 604

Exp. 12: Castings, Etc.

Cast iron can be formed by melting together iron and other metals. Then cool to show that they have recombined into a new material.

Ibid., Miller, p. 498

Great variety of fluids - milk - mercury - ``blue liquid''

Exp. 13: Bladder of air and stopcock - resists the hand

Squeeze the bladder. Open stopcock and resistance goes away.

Exp. 14: Jet impels other bodies - vanes - windmill

Resistance of wind in running, pressure of wind in sailing.

Exp. 15: The pop gun

Potato gun

``... I may press the air to a certain extent, but if I go on pressing, long before it comes to the second (potato plug) the confined air will drive the front one out with a force something like that of gunpowder;''

M. Faraday, Faraday's Chemical History of a Candle, annotated edition of The History of a Candle, Chicago Review Press, 1988, p. 61

Exp. 16: Weight

Balanced exhausted globe - air from bladder admitted. Air in the lecture room weighs 4500 pounds or about two tons.

Exp. 17: Gases can be coloured

nitrous acid gas, NO₂, can be used to show that gases can be colored.

Exp. 18: Gases can be combustible

olefiant gas, ethene, was burned to show the combustibility of a gas.

Exp. 19: Gases can behave as an acid

sulphurous, SO₂, and/or M.A. Gas, HCl, when in aqueous solution give an acid test with indicators.

Exp. 20: Gases can be incombustible

carbonic acid gas, CO₂, will not support combustion in a test tube.

Exp. 21: Gases can behave as an alkaline

Ammonia, NH₃, in a tube will turn moist litmus blue.

Exp. 22: Iodine

Crystallization of Iodine: Heated iodine in a tube will form crystals at the top inside surface of the tube as it cools.

Exp. 23: Water

A flask of boiling water with a balloon tied over it and covered by a large beaker will expand as the heating of the water continues.

[CHEMICAL CHANGES AND ATTRACTION]

Exp. 24: Magnet and suspended piece of iron

A piece of iron hanging from a string is attracted to a magnet.

Exp. 25: Feather and rubbed sealing wax

The feather is attracted to the wax that has been rubbed with sealing wax.

Exp. 26: Magnet and filings or turnings

Iron filings are attracted to a magnet.

Exp. 27: Pieces of ducht (dutch?) clay

In order for small pieces of clay to stick together they must be put into direct contact so as to get the small particles close enough to attract each other.

Exp. 28: Magnet and iron

See experiment 26.

Exp. 29: Two bullets

Two bullets show no attraction because of their large size.

Exp. 30: Pieces of Caoutchouc

two pieces of caoutchouc (soft, natural Malay rubber) are slightly warmed, then pressed together along two edges to fuse them into one piece. Opposite edges of single pieces are pressed together to form tubes and connectors.

M. Faraday, Chemical Manipulations, Phillips London, 1827, p. 206

Exp. 31: Adhesive powder as flower or meal

Some material (sulfur, talc, ground meal) is seen to adhere better (to glass, the hand) when ground fine than when ground coarse.

Faraday repeats that there is a difference between the attraction of large masses and the attraction among small particles: the latter must be brought very close together. This attraction en masse of small particles for each other must now be examined because it is especially important in chemistry.

Attraction of similar (read ``identical'') particles.

He points out that if a large number of identical, small particles are mutually attracted, the effect is adhesion. This is how gases assume the solid or fluid state. The degree of adhesion makes no essential difference in chemical properties. A block of solid behaves essentially the same as granules or powder; a pool of liquid, as droplets.

Exp. 32: Marbles in lumps - fragments and powder

lumps, chips, and powder of marble are manipulated. Perhaps with HCl, each to yield identical effervescence of CO₂, though probably at different rates.

Exp. 33: Mercury in mass

A sample of mercury is divided into smaller pieces in order to show constancy of fluidity, lustre, density, etc.

Exp. 34: Sulphur in mass

Chunks and powder of sulfur are melted to give identical liquids, and each is cooled by pouring into a basin of cold water to yield identical solids.

Attraction of dissimilar particles- very different:

different types of particles were put together and the products were observed.

Exp. 35: Phosphorus & iodine in air

striking effects. Heat produced, the old substances disappear and new ones appear altogether different. It is also found that particular quantities are best- This is chemical attraction or affinity. Some of its effects are transient as the evolution of light and heat and electricity.

Exp. 36: Iron in oxygen gas

iron reacts in oxygen gas to produce ferric oxide.

Exp. 37: Combustion-its great importance

methane or coal may have been burned in oxygen to produce heat, light, carbon dioxide and water. Change of properties is permanent.

Exp. 38: Solid become gases

Gunpowder: Saltpeter (Chinese snow) plus crushed sulfur and powdered charcoal were mixed and ignited. Sound, light and heat were released with several gases, very little ash remained.

H. C. Roscoe and C. Schorlemmer, Treatise on Chemistry, Vol. I, Macmillan, 1920, p. 362-366

Exp. 39: Glauber and Nitrate ammonia become fluids

solids of Glauber's salt (Na₂SO₄) and ammonium nitrate were dissolved in water to produce aqueous solutions.

Exp. 40: Fluids become gases

Alcohol and nitric acid: Ethyl alcohol and nitric acid are combined to produce gaseous products in a violent reaction.

Exp. 41: Fluids become solids

Sols mur lime and Carb Potash: Solutions of calcium chloride and potassium carbonate are mixed to yield a precipitate of calcium carbonate.

Exp. 42: Gases become solids

M A gas and ammonia: Vapors of hydrogen chloride and ammonia are brought together to produce a fuming white solid.

Exp. 43: Gases become solids

Hydrochloric acid is identified among several possible bottles by testing with a glass rod dipped in ammonia solution.

Exp. 44: Transparent to opaque

Baryta water & Sul acid: Barium sulfate is precipitated from clear solutions of barium hydroxide and sulfuric acid.

Exp. 45: Opaque to transparent

Recent Pho Lime & Mur acid: A suspension of calcium phosphate is clarified by addition of hydrochloric acid.

Exp. 46: Colorless col'd

Ferro prussi pot and sol iron: Solutions of potassium ferrocyanide and a ferric salt are mixed to precipitate the dye Prussian blue.

Exp. 47: Colorless col'd

Syrup and P A: Phosphoric acid is added to syrup of violets, giving an acidic (red) solution.

Faraday now proceeds to demonstrate attraction of small dissimilar particles.....

Exp. 48: Sulfur & Oxygen - Sul Acid

Sulfur burned in the presence of oxygen to produce acid anhydride, sulfur dioxide, together with some SO₃. Dissolved in water it gives acids.

Exp. 49: Phosphorus in Air - its acid properties

Phosphorus burns in oxygen to produce acid anhydride. When this product is placed in water it forms acid solution.

Exp. 50: Sul Acid & lump caustic lime - Sul lime

Sulfuric acid is mixed with calcium hydroxide to produce calcium sulfate and water. This is an example of neutralization.

Exp. 51: Potassium in water- alkali

A pea-sized piece of potassium is added to water. An explosive reaction results because of the release of hydrogen gas and heat. Potassium hydroxide (alkali) is produced.

Exp. 52: Zinc in crucible - oxide

Zinc powder is heated in a crucible. The zinc reacts with the oxygen in air to produce an oxide of zinc.

Exp. 53: Acid on coloured tests - then together

Vague. Perhaps an indicator is added to an acid and the color change is observed. A base is then added and a different color change occurs.

Exp. 54: Ammonia to clear solution phosphate lime in water

Ammonia (with strong odor) is bubbled into a solution of calcium phosphate. The odor disappears because of the formation of ammonium phosphates and insoluble calcium hydroxide.

Exp. 55: Sol caustic potash to Mur Ammonia

A solution of potassium hydroxide is mixed with a solution of ammonium chloride. A strong odor results because of the production of ammonia and potassium chloride.

Substances & Affinity

Exp. 56: Mercury in Nitrate of silver

A cloth bag of mercury suspended in silver nitrate solution slowly produces silver crystals on the cloth surface.

Exp. 57: Copper in Nitrate of mercury

Solid copper in mercury nitrate solution reduces mercury to its elemental form and slowly turns the solution to a blue color.

Exp. 58: Lead in Nitrate of copper

Solid lead added to blue copper nitrate solution reduces copper to its elemental form as the color of the solution gradually fades.

Exp. 59: Zinc in nitrate of lead

Solid zinc in lead nitrate solution results in rapid growth of lead crystals.

Exp. 60: Nitrate of Copper & tin foil

Copper nitrate crystals are wrapped in tin foil. Violent reaction often occurs.

[CAUSES THAT INFLUENCE AFFINITY]

Experiments in this section are used to demonstrate the causes that influence chemical reaction rates either as accelerators or inhibitors.

Aiding causes

Exp. 61: Antimony in chlorine

piece of antimony: The reaction of solid antimony in chlorine gas is fairly rapid; the rate increases as the size of antimony particles decreases.

Exp. 62: Zinc foil in air pieces

With the aid of heat, zinc foil will ignite; finely divided zinc may ignite spontaneously with a bluish flame.

Exp. 63: Lead pyrophorus pieces

When lead is prepared in a finely powdered form it will burn spontaneously in air.

Exp. 64: Tartaric acid carb soda & water

A mixture of two solids, tartaric acid sodium carbonate, is unreactive. The addition of water to form a solution will cause the evolution of carbon dioxide gas. Alka Seltzer.

Affinity influenced by presence of other bodies

The addition of certain substances will cause reactions to occur that otherwise might not take place under normal conditions.

Solution

Exp. 65: Silica divided & in Solution

Silica (crystalline) and its conversion to silica divided. ``Silica divided is obtained by heating colorless quartz to redness and quenching it in water. The mineral is thus rendered friable by this treatment and is easily reduced to a fine powder. This form is amorphous and is much more easily attacked by solvents than is the crystalline variety.''

Ibid., Miller p. 212

Exp. 66: Metallic Solution

Sodium or potassium is ``dissolved'' in water. Or possibly amalgam of sodium and/or potassium was shown?

Pressure

Exp. 67: Sulphur & chlorate potash -- detonating pellets

``Caution . Chlorates of potassium should not be kept with sulfur in considerable quantity, as the mixture may explode spontaneously. It was proposed by Berthollet to substitute this salt for nitre, in the preparation of gunpowder and the attempt was made at Essone in 1788: but as might have been expected, no sooner was the mixture submitted to trituration than it exploded with violence and proved fatal to several people.''

J. W. Webster, Manual of Chemistry, Marsh, Capen, Lyon & Webb, Boston, Massachusetts, 1839, p. 317

Heat

Exp. 68: Fulminating mercury -- combustion

``By dissolving one grain of mercury in 20 grains of nitric acid diluted with about 50 of alcohol, the new compound is deposited in crystals, which, when dry, detonate with the slightest friction.''

Ibid.. Miller, p. 258

Exp. 69: Burn Lead

By oxygen blow pipe

Exp. 70: Platina & tin foil -- alloys

``According to Faraday -- In this state the platina and tin foil act so rapidly at common temperatures on oxygen and hydrogen gases mixed in the ratio of 1 to 2, that it often becomes red hot and kindles the mixture.''

Ibid., Webster, p. 317

Exp. 71: Fulminating Powder

Mercury fulminate reacts with sodium chloride to give sodium fulminate and mercury chloride.

``A Powder may be produced when fulminates are boiled with a solution of NaCl or KCl thus converting it into a compound termed isocyanuric or fulminuric acid. This process renders it only slightly explosive.''

Ibid., Miller, 259

Heat sometimes diminishes the agency after having increased it.

Exp. 72: Mercury & Oxygen

Mercury forms mercuric oxide when heated gently in air. At higher temperatures the mercuric oxide reverts to its elements.

Exp. 73: Silver and oxygen

Silver oxide cannot be readily made by direct synthesis. Indeed it decomposes on heating. It can be readily made by adding base to a solution of silver nitrate.

Exp. 74: Fulminating silver--Azotane

``Fulminating silver is prepared by allowing silver oxide (Ag₂O) to come in contact with Ammonia solution. It turns black and the powder is explosive. NAg₃ -- similar to NH₃.''

I. Remsen, Chemistry , Henry Holt and Company, New York, New York, 1899, p. 532

Exp. 75: Carbonate of Lime-oxide of manganese

``The Oxide (of Manganese) obtained is of a greenish gray colour; it does not absorb oxygen at all so rapidly as the hydrated oxide; but if it be exposed to the air while hot, it rapidly becomes brown, or even burns. But it is best obtained by mixing together chloride of manganese, and carbonate of lime, and exposing them in a kind of platinum crucible to full red heat. The Chloride of lime and the Carbonate of Manganese being formed. The Carbonic acid is, however, driven off by the high temperature. The oxide obtained at this high temperature has no tendency to combine further with oxygen under ordinary circumstances, and may hence be easily preserved.''

R. Kane, Elements of Chemistry, Harper & Brothers, New York, New York, 1842, p. 353.

Exp. 76: Spongy platinum and jet of hydrogen

``Platinum has the remarkable property of causing the union of hydrogen and oxygen to produce water. Effect was discovered by Dobereiner.''

Ibid., Webster, pp. 316-7

Exp. 77: Ammonia through iron & glass tubes

``Passed ammonia gas over a coil of iron in a red hot porcelain tube and the gas expands and is resolved into its constituents (hydrogen and oxygen).''

Ibid., Webster, p. 210

Nascent state and its influence:

``Many gases which cannot be made to unite directly, nevertheless combine readily in their nascent state; that is while in the act of assuming the gaseous form by the decomposition of some of their solid or fluid combination.''

Ibid., Webster, p. 21

Exp. 78: Oxygen and hydrogen gases do not combine

There is no reaction between these two gases because they are not in the nascent state.

Exp. 79: M Acid on zinc evolves hydrogen

Hydrochloric acid is attacked by zinc and produces nascent hydrogen gas.

Exp. 80: M acid on oxide of zinc- evolves water

Hydrochloric acid and zinc oxide produces water and zinc chloride; hydrogen and oxygen are nascent and combine to make water.

Exp. 81: N Acid on tin - ammonia formed

Nitric acid and tin react to produce tin oxide plus oxides of nitrogen and some ammonia. Tin pulls oxygen out of nitric acid and leaves nascent hydrogen and nitrogen to make ammonia.

Exp. 82: Bottle of Chlorine - on sol indigo

``Chlorine rapidly bleaches the organic pigment of indigo bisulfate. Assisting (according to Faraday).''

Ibid., Webster, p. 457

Exp. 83: Bottle of bleaching powder on sol indigo

``Chloride of lime (containing some calcium hypochlorite) also acts as a bleach but decolorizes more slowly, showing the retarding effect of the lime on the bleaching power of chlorine.''

Ibid., Webster, p. 243

Affinity between the combining substances increases through the following three examples -- thus more precipitate each time:

Exp. 84: Mur lime & sol ammonia

Calcium chloride combined with ammonia solution -- slight or no precipitation of calcium hydroxide.

Exp. 85: Mur lime and carb ammonia

Calcium chloride and ammonium carbonate react to give a definite white precipitate of calcium carbonate.

Exp. 86: Sul Soda- Mur Bartyra

Sodium sulfate combines with barium chloride to form a very heavy white precipitate of barium sulfate.

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