Div. III. Decompofition of Nitrate of Ammoniac; Preparation of refpirable Nitrous Oxide.

Div. IV. Experiments and Obfervations on the Compofitions of Nitrous Gas, and on its Abforption by different Bodies.

Div. V. Experiments and Obfervations on the Compofition of Nitrous Oxide from Nitrous Gas, and Nitric Acid in different Modes.

Refearch II. Into the Combinations of Nitrous Oxide, and its Decompofition.

Div. I. Experiments and Obfervations on the Combinations of Nitrous Oxide.

Div. II. Decompofition of Nitrous Oxide by combuftible Bodies.

Research III. Relating to the Refpiration of Nitrous Oxide and other Gaffes.

Div. I. Experiments and Obfervations on the Effects produced upon Animals by the Respiration of Nitrous Oxide.

Div. II. Of the Changes effected on Nitrous Oxide and other Gaffes, by the Refpiration of Animals. Refearch IV. Relating to the Effects produced by the Refpiration of Nitrous Oxide, upon different Individuals. Div. I. Hiftory of the Discovery. Effects produced by the Refpiration of different Galles.

Div. II. Details of the Effects produced by the Refpiration of Nitrous Oxide upon different Individuals, furnished by themfelves.

Div. III. Abstracts from additional Details. Obfervations on the Effects of Nitrous Oxide, by Dr. Beddoes. Conclufion. Appendix.-No. 1. Of the Effects of Nitrous Oxide on Vegetables.

No. II. Table of the Weight and Compofition of the Combinations of Nitrogene.

No. IV. Defcription of a Mercurial Airholder, and Breathing Machine, by Mr. W. Clayfield.

No. V. Propofals for the Prefervation of accidental Obfervations in Medicine, by Dr. Beddoes.

The nature and properties of aeriform fluids, which have been fuccefsfully and particularly cultivated within thefe laft thirty years, have received a confiderable addition by the recent difcovery of the fingular properties of an aerial fluid, to which Dr. Priestley gave the name of dephlogifticated nitrous air; but which is now generally called the nitrous oxide. The great

ufe

ufe which may be made of thofe properties in medical cafes, renders the fubject important, and an accurate investigation of the nature of this nitrous oxide neceffary. Such an inveftigation forms the fubject of the work which is at prefent under examination; and it must be acknowledged, that its author appears to have beftowed much labour and attention upon it.

The Table of Contents is followed by a fhort Preface, which contains a concife fketch of the work; and wherein Mr. Davy acknowledges his obligations to Dr. Beddoes, for his affiftance in contriving several experiments, &c.

The various opinions which were entertained by philofophers relatively to the quantities of the component principles of the nitrous acid, as alfo with refpect to the quantity of nitrous gas which is neceffary to faturate a given quantity of oxygene, induced Mr. D, to investigate means of determining with accuracy the compofition of nitrous acid, in its different degrees of oxygenation. With this view he contrived and executed various experiments, the account of which is contained in the firft Divifion, wherein the reader will meet with feveral judicious remarks.

The principal refults of the above-mentioned experiments are expreffed in three Tables, of which we fhall transcribe the firft and fecond, as being the most useful.

"TABLE I. Containing Approximations to the Quantities of Nitric Acid, Nitrous Gas, and Water in Nitrous Acids, of different Colours and Specific Gravities.

"The blue green acid is not homogeneal in its compofition, it is compofed of the blue green fpherules and the bright green acid. The blue green fpherules are of greater fpecific gravity than the dark green acid, probably becaufe they contain little or no water.

"The compofition of the acids thus marked, is given from calculation.

" TABLE

TABLE II. Binary Proportions of Oxygene and Nitrogene in Nitric

and Nitrous Acids*.

Dark green

The fecond fection commences with the following paragraphs:

"The formation and decompofition of volatile alkali in many proceffes, was obferved by Priestley, Scheele, Bergman, Kirwan, and Higgins; but to Berthollet we owe the difcovery of its conftituent parts, and their proportions to each other. These proportions this excellent philofopher deduced from an experiment on the decompofition of aëriform ammoniac by the electric fpark: a process in which no apparent fource of error exists.

Since, however, his eftimations have been made, the proportions of oxygene and hydrogene in water have been more accurately deter mined. This circumftance, as well as the conviction of the impoffibility of too minutely fcrutinizing facts, fundamental to a great mafs of reasoning, induced me to make the following experiments." P. 56.

This is followed by the narration of the experiments, the refult of which is, that the nitrogene in ammoniac is to the hydrogene, as 35 to 105 in volume; and 13.3 grains of ammoniac are composed of 10,6 nitrogene (supposing that 100 cubic inches weigh 30,45 grains) and 2,7 hydrogene.

In the fame fection, we also find an examination of the specific gravity of ammoniac; an investigation of the quantity of ammoniac in different aqueous folutions; and various other particulars concerning ammoniac.

It is fomewhat fingular, that in certain places this author ftill seems to entertain the idea of phlogifton, and accordingly fays, that certain fubftances are dephlogifticated or phlogifticated, when almost all'other philofophical chemifts would fay, that thofe fubftances are oxygenated or deoxygenated. But there is a fingularity of style obfervable throughout the work. Speaking of the non exiftence of ammoniacal nitrates, "I attempted," this author fays, " in different modes to combine nitrous acids with ammoniac, fo as to form the falts which

"Nitrous gas contains 44,05 nitrogene, and 55,95 oxygene, as has been faid before."

PP

ERIT. CRIT. VOL, XVII, MAY, 1801.

have

have been fupposed to exist, and called nitrites of ammoniac ; but without fuccefs." He then relates fome experiments, and concludes that no fubftance properly fo called exifts.

The third Divifion contains the principal facts which have been afcertained concerning the production, the specific gravity, and other properties of the nitrous oxide. The very curious nature of thofe properties, induces us to transcribe such paffages of this Divifion, as may give our readers a competent idea of the fubject.

"ift. Compact, or dry nitrate of ammoniac, undergoes little or no change at temperatures below 260°.

"2dly. At temperatures between 275° and 300°, it flowly fub Himes, without decompofition, or without becoming fluid.

"3dly. At 320° it becomes fluid, decompofes, and fill flowly fublimes; it neither affuming, or continuing in, the fluid ftate, without decompofition.

"4thly. At temperatures between 340° and 480°, it decomposes rapidly.

5thly. The prifmatic and fibrous nitrates of ammoniac become fluid at temperatures below 300°, and undergo ebullitions at temperatures between 360° and 400°, without decompofition.

"6thly. They are capable of being heated to 430° without decompofition, or fublimation, till a certain quantity of their water is evaporated.

7thly. At temperatures above 450° they undergo decompofition, without previously fofing their water of cryftalifation." P. 85.

"Two hundred grains of compact nitrate of ammoniac were introduced into a glafs retort, and decompofed flowly by the heat of z fpirit lamp. The first portions of the gas that came over were reject ed, and the laft received in jars containing mercury. No luminous appearance was perceived in the retort during the process, and almoft the whole of the falt was refolved into fluid and gas. The fluid had a faint acid taste, and contained fome undecompounded nitrate. The gas collected exhibited the following properties:

"a. A candle burnt in it with a brilliant flame, and crackling noife. Before its extinction, the white inner flame became furrounded with an exterior blue one.

b. Phofphorus introduced into it in a state of inflammation, Burnt with infinitely greater vividness than before.

"c. Sulphur introduced into it when burning with a feeble blue fame, was inftantly extinguished; but when in a state of active inflammation (that is, forming fulphuric acid); it burnt with a beautiful and vivid rose-coloured flame.

"d. Inflamed charcoal, deprived of hydrogene, introduced into it, burnt with much greater vividnefs than in the atmosphere.

"e. To fome fine twisted iron wire a small piece of cork was affixed: this was inflamed, and the whole introduced into a jar of the air. The iron burned with great vividnefs, and threw out bright parks as in oxygene.

"L Thirty

"f. Thirty measures of it expofed to water previoufly boiled, was rapidly abforbed; when the diminution was complete, rather more

than a measure remained.

66 g. Pure water faturated with it, gave it out again on ebullition, and the gas thus produced retained all its former properties.

"b. It was abforbed by red cabbage juice; but no alteration of colour took place.

"¿. Its tafte was diftinctly sweet, and its odour flight, but agreeable. j. It underwent no diminution when mingled with oxygene, of nitrous gas." P.86.

"We may conclude, that 100 cubic inches of pure nitrous oxide weigh 50,1 grains at temperature 50°, and atmospherical preffure 37.

"I was a little furprifed at this great fpecific gravity, particularly as I had expected, from Dr. Priestley's obfervations, to find it lefs heavy than atmospherical air. This philofopher fuppofed, from fome appearances produced by the mixture of it with aëriform ammoniac, that it was even of lefs fpecific gravity than that gas."

"Thus in nitrate of ammoniac, four affinities may be supposed to exift.

I.

"1. That of hydrogene for nitrogene, producing ammoniac. "2. That of oxygene for nitrous gas, producing nitric acid.

3. That of the hydrogene of ammoniac for the oxygene of nitric acid.

4. That of the nitrogene of ammoniac for the nitrous gas of nitric acid.

"At temperatures below 300°, the falt, from the equilibrium between thefe affinities, preferves its existence.

"Now, when its temperature is raised to 400°, the attractions of hydrogene for nitrogene, and of nitrous gas for oxygene, are diminifhed; whilft the attraction of hydrogene for oxygene is increased; and perhaps that of nitrogene for nitrous gas.

Hence the former equilibrium of affinity is deftroyed, and a new one produced.

"The hydrogene of the ammoniac combines with the oxygene of the nitric acid to generate water; and the nitrogene of the ammoniac enters into combination with the nitrous gas to form nitrous oxide: and the water and nitrous oxide produced, most probably exist in binary combination in the aëriform state, at the temperature of the decompofition.

"But when a heat above 800° is applied to nitrate of ammoniac, the attractions of nitrogene and hydrogene for each other, and of oxygene for nitrous gas, are ftill more diminished; whilft that of nitrogene for nitrous gas is deftroyed, and that of hydrogene for oxygene increased to a great extent: likewife a new attraction takes place; that of nitrous gas for nitric acid, to form nitrous vapour. Hence a new arrangement of principles is rapidly produced; the nitrogene of ammoniac having no affinity for any of the fingle principles at this temperature, enters into no binary compound: the oxygene of the nitric acid forms water with the hydrogene, and the nitrous gas combines with the nitric acid to form nitrous vapour. All these substances moft

Pp2

probably