The 1827 Christmas Lectures
of Michael Faraday

Lecture #5

Sulphur, Phosphorus, Carbon and their Acids

In Lecture 5 of the 6 part series, Faraday presents the chemistry of carbon, phosphorus, and sulfur. Certain materials that are combustible exist in the solid state. The three elements presented are notable examples.

Faraday begins by illustrating sulfur's physical appearance under various conditions (Exp. 1-4) and then moves on to its combustion (Exp. 5). Next, he uses the gaseous product of the combustion for several demonstrations (Exp. 6-10), most of which exhibit its acidic and bleaching properties. Faraday finishes the topic of sulfur with demonstrations of sulfuric acid and its properties (Exp. 11-17).

For phosphorus, Faraday leads the audience through a series of sixteen experiments, first demonstrating its physical properties (Exp. 18-21), and then demonstrating combustion and the creation of phosphoric acid (Exp. 22-24). He then uses a familiar example, bone, from which phosphorus can be extracted (Exp. 25-29). Lastly, he manufactures phosphine and illustrates its properties (Exp. 30-33).

The third portion of Lecture 5 concerns carbon and the gases which result from its combustion. Faraday shows examples of carbon produced by various reactions (Exp. 34-36). Then, carbon is burned in oxygen and the gas, CO₂, is tested (Exp. 37-47). Methane gas is also produced and tested to end the lecture (Exp. 48-55).

In presenting his lectures, Faraday uses a timeless pedagogy which makes use of demonstrations, discussions, and linkages. He uses simple language, minimal jargon, and no mathematics. The demonstrations are related to everyday life, but some of them are too dangerous for the modern day teacher to use. Nevertheless, Faraday presents an example of exemplary teaching and shows us how the learning of science can be made both relevant and entertaining.

SULFUR

Exp. 1: Sulfur rubbed

attracts feather or down not soluble in water - heavier than water S.G. 1.99- It does not change in air - when heated it melts - at first is fluid- then thicker. Solid sulfur becomes charged with rubbing.

Exp. 2: Sulfur melted in a flask

Solid sulfur is heated gently and melted. Liquid flows readily.

Exp. 3: Thickened sulfur

The sulfur sample is further heated and becomes more viscous.

Exp. 4: Sublimed sulfur

Sulfur vapor is allowed to recondense into the solid form.

Exp. 5: Flower sulfur over Argand lamp burns much more brilliantly in oxygen gas

The sulfur sample is heated over an oil lamp until it ignites, and then it is placed in oxygen gas.

Exp. 6: Sulfur in oxygen (resume the results)

The result is an acid- sulfurous acid and it is gaseous when pure. Save the gas produced from Exp. 5. This is sulfur dioxide.

Exp. 7: Bottles of sulfurous acid gas

Bottles of gas previously made are shown.

Exp. 8: Reddens litmus or cabbage liquor-bleaches.

Solutions of litmus and cabbage juice are added to the gas bottles. A piece of fabric is added to a gas bottle and is bleached.

Exp. 9: Extinguishes a light even mixed with air

A sample of pure gas is poured directly on a burning candle.

Exp. 10: Extinguishes a light when diluted has a suffocating odour

is heavy. A sample of gas that has been previously opened to the air is poured directly on a candle. A sample of gas is poured toward the audience until the odor is detected.
[Rose bleach] A red rose is inserted into a bottle of gas. The rose becomes bleached.

Exp. 11: Specimens of Sul Acid

Bottles of sulfuric acid previously made are shown. Has high density particularly when concentrated.

Exp. 12: Little oil vitriol to much cabbage liquor or water and litmus

A small amount of sulfuric acid is added to large quantities of cabbage juice and litmus solution.

Exp. 13: S.A. to paper - black acid - an invisible ink

Concentrated sulfuric acid is used to write on a white sheet of paper.

Exp. 14: Invisible writing rendered visible

A sample of dilute sulfuric acid is used to make invisible writing visible.

Exp. 15: Heated Sulfuric acid

sulfurous acid does not do this. A sample of concentrated sulfuric acid is heated with an oil lamp and fumes. Aqueous sulfur dioxide invisibly degassifies.

Exp. 16: Dilute acid and fire phosphorus

Water is added to a sample of strong sulfuric acid. The heat produced by this reaction is sufficient to ignite a sample of phosphorus. CAUTION!

Exp. 17: Little S.A. in bottle of Amm - salt is formed

Add sulfuric acid to ammonia. Ammonium sulfate is formed and the acid is neutralized.

PHOSPHORUS

Exp. 18: Solutions of phosphorus

phosphorus is dissolved in oil and in ether.

Exp. 19: Phosphorus on brown paper

A piece of phosphorus is placed on brown paper. Ignites?

Exp. 20: Phosphorus in capsule

not fire paper readily dense fumes are produced these are phosphoric acid. This phosphorus and brown paper is placed inside a container and allowed to combust. This produces dense smoke consisting partly of phosphorus pentoxide.

Exp. 21: Phosphorus in dry basin under bell glass

Phosphorus stable in vacuo.

Exp. 22: Phosphorus and oxygen

sun in bottle - The results are phosphoric acid. Pure oxygen is introduced into the evacuated bell jar and the phosphorus ignites with a brilliant flame. Phosphorus pentoxide is produced.

Exp. 23: The white flakes dissolved in water

Phosphorus pentoxide is dissolved in water to yield phosphoric acid.

Exp. 24: Change of colour by them

are very sour. The solution from Exp. 23 is added to vegetable dyes which change color. Tasted. (Not recommended.)

Exp. 25: Specimens of bone ash and [red-colored] glass of phosphorus.

Red phosphorus in ampoule.

Exp. 26: Retort and furnace arranged

crude phosphorus - thus this insipid inert white ash left when bones are burnt is made to yield this extraordinary body phosphorus. Bone meal is placed in a retort and furnace and burnt to produce bone ash -- phosphate of lime. Carbon added?

Exp. 27: Phosphorus bottle and matches another method of obtaining light is by friction

A sample of phosphorus in a bottle is displayed along with matches.

Exp. 28: Piece of phosphorus matches & a cork

The phosphorus match is struck against a piece of cork and fails to ignite?

Exp. 29: Muslin in phosphate ammonia

An attempt is made to light a piece of muslin impregnated with ammonium phosphate - prevents combustion.

Exp. 30: Phos hydrogen prepared

inflames spontaneously in the air. Phosphine gas is prepared by placing a piece of phosphorus in sodium hydroxide solution. Coal gas is bubbled through as the solution is heated.

Exp. 31: Rings of smoke

are Phos acid & water. As the bubbles of phosphine generated above reach the air, they ignite and form smoke rings of phosphoric acid.

Exp. 32: Bubbles in oxygen gas

Faraday's meaning is unclear but presumably the ignition of the phosphine would be more brilliant in oxygen than in air.

Exp. 33: Bottles of gas

- may be thus preserved a few hours. Faraday's meaning is unclear.

CARBON

Exp. 34: Burn writing paper

Burn paper to produce charcoal or carbon - black insoluble substance.

Exp. 35: Sul acid to paper

- this too is carbon. Dehydration of cellulose a carbohydrate by concentrated sulfuric acid.

Exp. 36: Wine & charcoal

- cleanses putrid substances. Activated charcoal decolorized red wine and absorbs foul vapors. Burnt toast is a folk remedy for an upset stomach.

Exp. 37: Charcoal in oxygen

dissolves and a gas remains equal in bulk to the oxygen - this is Carbonic acid gas. Burns (dissolves?) charcoal in oxygen to yield an equal volume of carbon dioxide.

Exp. 38: Carb acid gas procured

Carbon dioxide is obtained from marble chips by the addition of dilute hydrochloric acid.

Exp. 39: Bottles and jars of it

Carbon dioxide collected by downward displacement.

Exp. 40: Extinguishes taper

and it also destroys life if the attempt be made to respire it. Extinguishes flame. Destroys life. (presumably not demonstrated)

Exp. 41: Gas remains in upright jar

taper - then pour it into another jar with a burning taper. Test with taper then pour gas into another jar with containing burning candle.

Exp. 42: One of former jars and the taper again

Grotto del'Cane -The famous Italian grotto is used as a natural example to illustrate the high density of carbon dioxide. (See Bull. Hist. Chem. 1988, 1, p. 10-13)

Exp. 43: limewater test

Familiar reaction of carbon dioxide and calcium hydroxide solution to produce precipitate of calcium carbonate.

Exp. 44: Bell glass, candle, and limewater

Candle is ignited inside bell glass which contains limewater. Precipitate forms.

Exp. 45: Nooth's apparatus

and by force much may in this way be condensed. This apparatus was used to produce carbonated water. [See Bull. Hist. Chem. 1989, 5, p. 40]

Exp. 46: Soda water, beer, champagne, etc

contain it (Cyder) All these substances contain carbon dioxide.

Exp. 47: Glass of cyder or beer under air pump

As pressure falls, carbon dioxide bubbles from solution.

Exp. 48: Burn from jet

no water but carbonic acid. Carbon monoxide is burned. No water is produced. Carbon dioxide detected with limewater.

Exp. 49: Oleft gas made

Ethylene produced by heating 4 cm³ sulfuric acid and 1 cm³ ethanol)

Exp. 50: Bottles and jars of it

Colorless, in soluble samples of carbon monoxide displayed.

Exp. 51: Oleft gas burnt

Carbon dioxide is formed by combustion. Limewater test.

Exp. 52: Candle

and here similar substances are burning. Faraday, perhaps unknowingly, makes the connection between (CH₂) and -(CH₂)n

Exp. 53: Oleft gas and chlorine fired

blue liquor or litmus paper

Exp. 54: Bladder or vessel of gas or jet

(Methane from gas jet.)

Exp. 55: Roll of brown paper

lighted at one end either burn it by flame at one end or by inclining it, can carry gas up the middle and cause jet of flame at the other end. Shows production of flammable gas by partial combustion of paper.

Editors

Andrew Peterson, Judy Phillips, Ruth Rand, Kay Reat, Debra Reynolds, Mary Rothermich, Roger Rumppe, Ely Jose (Jay) Salon.

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