rebounds from the ftroke of the peftle. It is fo deliquefcent, as in a few minutes to be covered with drops, when expofed to the air, and to become oily in its confiftence. It destroys, in a great degree, the colour of fyrup of violets, after having changed it to a deep green. It raifes a violent heat when thrown in powder into water, and exhales in its folution a greafy urinous fmell,' (une odeur groffe & lixivielle.)

A

• The Reflections on the Neceffity of employing the volatile Alkali, in a State of Gas, in delicate Experiments,' are juft and proper. In many inftances, the refult of experiments is very different from what we may expect, when the best fluid alkali is employed. The way we have commonly ufed, is to put fome common alkaline fpirit into a phial, to which a cork is fitted, perforated with a bent tube. The bottom of this phial is a little heated, fo as to expel the atmospheric air, and the other leg is inferted into another bottle prepared in the fame way, in which the liquor to be examined has been previously put. It is needless to add, that the bottoms of the phials must be round and thin, to bear the heat of a lamp furnace. M. Fourcroy puts the fluor in a fmall retort, and immerfes the neck into the fluid to be examined.

Our author's opinion of the Caufe of the Deliquefcence and Eflorefcence of Neutral Salts,' is of no great importance. The latter is owing to the air attracting the water of crystallization; the former to the contrary caufe. He obferves, that thofe falts which cryftallife eafily, in large cryftals, are fubject to efflorefcence; the others to deliquefcence.

The impurity of the Epfom falt commonly exported, our author finds to arife from marine magnesia mixed with it. The former is efflorefcent, the latter deliquefcent; and from want of properly distinguishing the genuine falt from its impurity, different accounts of its nature, in this refpect, have been given by able chemists. The marine magnefia is about one fiftieth part of the whole.

The liver of arfenic, or the combination of the common white arfenic and a fixed alkali, has no marks of a neutral; but to form a neutral falt the nitrous acid must be distilled from the arfenic, more completely to feparate the phlogiston. The difference of the arfenic in these feparate ftates is the subject of our author's remarks; and he explains them according to Lavoifier's fyftem.

; M. Fourcroy next examines the phenomena which arife from rubbing kermes mineral, fulphur, and antimony, with fixed cauftic alkali. This enquiry is chiefly intended to afcertain the purity of kermes mineral, which, when well washed, and triturated without heat with this alkali, exhales a foetid fmell, and changes to an orange colour, with a foft confiftence. This true liver of fulphur with antimony is foluble in water. The effay before us is, in many other refpects, highly

curious;

the head of the lift. By this means, we fhall at once perceive the effects of mixture, both in confequence of fingle and double elective attraction.

A defcri tion of the apparatus for examining, in miniature, the effect of dephlogisticated air, conveyed to the furface of an inflamed coal on bodies expofed to the brifk heat which it excites,' next follows. The method is neat and convenient; but it must be examined with the plate. We then meet with Remarks on the Cause of the Ebullition of Water, and on the Phenomena which accompany it.' This appearance M. Fourcry thinks depends on the water affuming the form of gas, and is attended with every circumftance which accompanies the fame change in other fluids. We think it may be more properly confidered as a feparation of gas, in confequence of the greater affinity of heat to the humour; becaufe, though ever fo much agitated with the latter, it will not unite till the heat is again feparated. Perhaps this feparated steam may differ in its nature from the remaining water; but it more probably differs only in form. In this view, we fee how the gas is eafily united to air, and in confequence of a mutual attraction, for every chemist knows, that attraction, is more powerfully exerted when bodies refemble each other in form; and we fee too how evaporation may go on in vacuo, which, on the footing of its depending on chemical folution only of water in air, has been fuppofed inexplicable.— 'But it is not our bufinefs to write differtations, though we may fuggeft hints for the use of others.

M. Fourcroy next defcribes a crystallized feldt-fpath, found mixed with rock cryftal and mica, in the neighbourhood of Alençon. The Obfervations on Incombustibility, confidered as a Character of Salts in general,' are connected with M. Lavoifier's new fyftem, of which we meet with a clearer account in this volume than we have hitherto feen; but it is too long for an extract. The principal point which may be styled new, is to prove that falts, and particularly alkalies, confift of a combuftible body, combined with pure air. Our author thinks too, that alkalies exift not only potentially but formally in vegetable fubftances: this opinion is now pretty general on the continent.

The fubject which follows is on the Difficulty of obtaining the fixed cauftic Alkali, in a very pure and folid Form.' Our author's precautions for this purpofe, are remarkable only for the great attention with which he prevents the access of common air at laft, the alkali does not drop into the phial, but through a body of quick lime, and it is evaporated with equal addrefs in clofe veffels. The properties of this falt, when quite pure, we fhall felect; for in this ftate it has feldom been deicribed. Its fufibility is fo great, that it foftens by a flight heat, and it becomes very hard by cold: when it is expofed to a temperature of 4 or 5 degrees below o (from 23 to 21° of Fahrenheit), it is fo hard as to be with difficulty powdered, and

re

rebounds from the ftroke of the peftle. It is fo deliquefcent, as in a few minutes to be covered with drops, when expofed to the air, and to become oily in its confiftence. It destroys, in a great degree, the colour of fyrup of violets, after having changed it to a deep green. It raifes a violent heat when thrown in powder into water, and exhales in its folution a greafy urinous finell,' (une odeur groffe & lixivielle.)

• The Reflections on the Neceffity of employing the volatile Alkali, in a State of Gas, in delicate Experiments,' are juft and proper. In many inftances, the refult of experiments is very different from what we may expect, when the best fluid alkali is employed. The way we have commonly ufed, is to put fome common alkaline fpirit into a phial, to which a cork is fitted, perforated with a bent tube. The bottom of this phial is a little heated, fo as to expel the atmospheric air, and the other leg is inferted into another bottle prepared in the fame way, in which the liquor to be examined has been previously put. It is needlefs to add, that the bottoms of the phials must be round and thin, to bear the heat of a lamp furnace. M. Fourcroy puts the fluor in a fmall retort, and immerfes the neck into the fluid to be examined.

Our author's opinion of the Caufe of the Deliquefcence and Eflorefcence of Neutral Salts,' is of no great importance. The latter is owing to the air attracting the water of cryftallization; the former to the contrary caufe. He obferves, that thofe falts which cryftallife eafily, in large crystals, are subject to efflo refcence; the others to deliquefcence.

The impurity of the Epfom falt commonly exported, our author finds to arife from marine magnesia mixed with it. The former is efflorefcent, the latter deliquefcent; and from want of properly distinguishing the genuine falt from its impurity, different accounts of its nature, in this refpect, have been given by able chemifts. The marine magnefia is about one fiftieth part of the whole.

The liver of arfenic, or the combination of the common white arfenic and a fixed alkali, has no marks of a neutral; but to form a neutral falt the nitrous acid must be diftilled from the arfenic, more completely to feparate the phlogifton. The difference of the arfenic in thefe feparate ftates is the fubject of our author's remarks; and he explains them according to Lavoifier's fyftem.

M. Fourcroy next examines the phenomena which arife from rubbing kermes mineral, fulphur, and antimony, with fixed cauftic alkali. This enquiry is chiefly intended to afcertain the purity of kermes mineral, which, when well washed, and triturated without heat with this alkali, exhales a fœtid fmell, and changes to an orange colour, with a foft confiftence. This true liver of fulphur with antimony is foluble in water. -The effay before us is, in many other refpects, highly CC 2 curious;

curious; but the length of our article obliges us to decline any farther examination of it.

The Obfervation on the flow Diffolution of Regulus of Antimony by the marine Acid,' only fhows, that it really acts on the metal after fome months, without the affiftance of heat, and produces the ufual preparations.

We next learn that lime-water, magnefia, terra ponderofa, and clay, deftroy the colour of Pruffian blue; and lime-water, digested on it, is a more convenient re-agent to difcover iron in water than the Pruffian alkali. It is remarkable that Pruffian blue, after its colour is deftroyed by alkalis, recovers it again on the addition of acids, and that the experiment may be often repeated.

The following obfervation teaches us, that nitrated mercury precipitates the fame coloured matter from milk as from urine; but that the alkaline bafis of the neutral is the fixed vegetable. Thefe experiments have not, however, been fufficiently diverfified, to induce us to explain the fact. We ftrongly fufpect a little inaccuracy.

The note on the fpiritus rector of the bile, which has the odour of amber, contains little except the fact itfelf. The last effay on the New Theory to explain the Phenomena of Combuftion, Calcination, the Decompofition, and Recompofition of Water and Acids, contains the explanation of fome modern difcoveries on the theory of M. Lavoifier. Additions to and corrections of the effay, to explain double elective attraction, by the help of numbers, conclude this inftructive volume, which has neceffarily drawn us to a greater length, than we propofed, by the variety of subjects, and the number of new and interefting facts. If our readers reap but a fmall fhare of the enter tainment and information which we have derived from it, they will regret the labour of reading, as little as we do that of writing this extenfive article.

MONTHLY CATALOGUE,

POLITICA

L.

Addrefs to the Stockholders; with a Propofal for the Amendment and better Security of their funded Property; earnestly recommended to their Confideration. 4to. 25. Murray.

THE

HIS Addrefs relates to a fubject of great national importance, the more speedy discharge of the public debt. The author obferves, that no minifter will be found hardy enough to propofe a tax upon our funded property; but he thinks, at the fame time, it is reasonable that the funds fhould contribute towards alleviating the burden of the nation. What he propofes, for this purpose, therefore, is a fpontaneous benevolence from the ftock-proprietors. The manner in which fuch a plan might

be

be moft conveniently carried into execution, he explains at fome length; and he warmly recommends it to the confideration of thofe to whom it is addreffed.

*

British Rights afferted; or, the Minifter admonished. 8vo. 6d. Scratcherd.

The fubject of this pamphlet is the fhop-tax, which the author reprefents as extremely unjust and oppreffive. He may be a fincere friend to the fhop-keepers, but is not a powerful advocate in their caufe.

The Tenth Chapter of the Acts of the Chancellor of the Exchequer. 8vo. 3d. Thornton.

From the title of this production, it feems as if the author had decimated the acts of the prefent minifter. What pity that nine fimilar chapters fhould be totally funk in oblivion! The fubject of this fragment is the fhop-tax, concerning which the author's wrath is kindled, and he chaftifes the chancellor of the exchequer in the venerable ftyle of the Old Teftament; but not with Scorpions.

A Reply to Sir Lucius O'Brien, Bart. By William Gibbons. 8vo. 15. 6d. Robinfon.

In our last Review, we gave an account of fome Letters written by this gentleman, concerning the trade and manufac tures of Ireland. Sir Lucius O'Brien contends that the apprehennon of any rivalfhip from the Irifh, in the iron-manufacture at least, is rendered entirely groundlefs by local circumstances; and that it may be queftioned whether, with regard to other articles of trade likewife, the pernicious confequences, fo much dreaded by the manufacturers of both countries, are not in a great measure chimerical. A correfpondence has fubfifted on this fubject, between Sir Lucius and Mr. Gibbons of Bristol, who, in this Reply, makes fome obfervations which tend to refute the opinion maintained by the baronet. As the controverfy can only be determined by a comparison of authenticated facts, it is fufficient for us, at prefent, to obferve, that Mr. Gibbons writes with great candour, and appears to be well informed in what relates to the iron trade.

A Retrospective View of the increafing Number of the Standing Army of Great Britain, from its firft Eftablishment in 1650, to the General Peace in 1784. 8vo. 15. 6d, Walter.

The author of this pamphlet traces the hiftory of standing armies in England, from the establishment of the yeomen of the guard, which he confiders as their origin, in 1486, under the reign of Henry the Seventh; obferving, that the inftitution was extended by Charles the Second, who, at different times, levied a regiment of foot, two troops of horfe, and two regiments of foot guards. From this period to the prefent time, the gradual progreffion of the army is afterwards recited; and GC 3

an