ance is not inconfiderable. I have purfued, not that which demands skill, and infures renown, but

That which before us lies in daily life.

"If I have been favoured with a measure of fuccefs, which has as much exceeded my expectation as my defert, I ascribe it partly to a difpofition in the public mind to encourage, in thefe days of alarm, attack, and agitation, any productions of which the tendency is favourable to good order and Chriftian morals, even though the merit of the execution by no means keeps pace with that of the principle. In fome inftances I truft I have written feasonably when I have not been able to write well. Several pieces perhaps of small value in themselves have helped to fupply in fome inferior degree the exigence of the moment; and have had the advantage, not of fuperfeding the neceffity, or the appearance, of abler writings, but of exciting abler writers; who, feeing how little 1 had been able to fay on topics upon which much might be faid, have more than fupplied my deficiencies by filling up what I had only fuperficially sketched out. On that which had only a temporary use, I do not aspire to build a lasting reputation." /P. xv.

This publication cannot poffibly fail of being highly acceptable to the world, for all muft be glad to poffefs the uniform collection of what, in their detached and feparate form, they have admired and approved. Such a mind, and fuch a pen, ought not to continue long unemployed; and we hope ftill to have repeated opportunity of announcing to the friends of virtue and religion the refult of Mrs. More's valuable labours.

ART. XVII. Refearches, Chemical and Philofophical; chiefly concerning Nitrous Oxide, or dephlogifticated Nitrous Air, and its Refpiration. By Humphry Davy, Superintendent of the Medical Pneumatic Inftitution. 8vo. 580 pp. Ios. 6d. Johnfon. 1800.

THIS work is divided into four primary parts, called ReJearches, each of which comprehends feveral Divifions, under the following titles:

Research I. Into the Analysis of Nitric Acid, and Nitrous Gas, and the Production of Nitrous Oxide.

Divifion I. Experiments and Obfervations on the Compofition of Nitric Acid, and on its Combinations with Water, and Nitrous Gas.

Div. II. Experiments and Observations on the Compofition of Ammoniac, and on its Combinations with Water and Nitrous Acid.

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 Respiration of Nitrous Oxide and other Gaffes.

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

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

Div. I. Hiftory of the Difcovery. Effects produced by the Refpiration of different Gaffes.

Div. II. Details of the Effects produced by the Ref piration of Nitrous Oxide upon different Individuals, furnished by themselves.

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

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

No. III.

Additional Obfervations.

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 acriform 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 dephlogisticated 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 concise sketch of the work; and wherein Mr. Davy acknowledges his obligations to Dr Beddoes, for his affistance in contriving feveral 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 first 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 tranfcribe the first 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 fpecific 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 spherules are of greater fpesific gravity than the dark green acid, probably because 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

Dark green

contain

70,50

29.50

70,10

29,90

69,63 30,37

69,08 30,92

The fecond fection commences with the following paragraphs:

"The formation and decompofition of volatile alkali in many pro ceffes, was obferved by Prisftley, 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 ex-. cellent philofopher deduced from an experiment on the decompofition of aëriform ammoniac by the electric fpark: a process in which no apparent fource of error exifts.

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 impoffi bility of too minurely 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 compofed of 10,6 nitrogene (fuppofing that 100 cubic inches weigh 30,45 grains) and 2,7 hydrogene.

In the fame section, we alfo find an examination of the fpecific gravity of ammoniac; an inveftigation 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 almoft all other philofophical chemifts would fay, that thofe fubftances are oxygenated or deoxygenated. But there is a fingularity of ftyle 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

BRIT. CRIT. VOL. XVII, MAY, 1801.

have

have been fuppofed 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 ascertained concerning the production, the specific gravity, and other properties of the nitrous oxide. The very curious nature of those properties, induces us to transcribe fuch 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 fublimes, without decompofition, or without becoming fluid.

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

4thly. At temperatures between 340° and 480°, it decompofes

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, cr fublimation, till a certain quantity of their water is evaporated.

thly. At temperatures above 450° they undergo decompofition, without previously lofing 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 a fpirit lamp. The firft portions of the gas that came over were rejected, and the last 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 ftate of inflammation, burnt with infinitely greater vividness than before.

66

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

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

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

5

"f. Thirty

1