veffel, till all the fulphur was driven off, and the mixture was of a light grey colour. He likewife was acquainted with the fact, that by a fufficient degree of fire in a clofe veffel this cineritious powder turned white. Mr. Turner alfo prepared this powder with a pound and a half of hart's-horn fhavings, and a pound of antimony, as well as with fmaller proportions of bone. Schroder prefcribes equal weights of antimony and calcined hart's-horn; and Poterius and Michaelis, as quoted by Frederic Hoffman, merely order the calcination of thefe two fubftances together (aligning no proportion), in a reverbatory fire for feveral days. In the London Pharmacopeia of 1788, this powder is called pulvis antimonialis; and it is directed to be prepared by calcining together equal weight of hart's-horn fhavings and antimony.'

On a comparative examination of the pulv. antimonialis of the laft corrected London Pharmacopeia, the appearances were precifely the fame; and there is little doubt, from a chemical examination, which we can confirm by obfervation on the effects, that it is the fame medicine eflentially and formally. The colour is not always conftant, owing to circumitances which we need not stop to explain. We thall fubjoin the conclufion, in Dr. Pearfon's own words.

From the whole of the above analytical experiments it appears: 1. That James's powder confifts of phofphoric acid, lime, and antimonial calx; with a minute quantity of calx of iron, which is confidered to be an accidental fubflance.

2. That either, thefe three effential ingredients are united with each other, forming a triple compound, or, phofphorated lime is combined with the antimonial calx, compofing a double compound in the proportion of about 57 parts of calx, and 43 parts of phospho:ated lime.

3. That this antimonial calx is different from any other known calx of antimony in feveral of its chemical qualities. About threefourths of it are foluble in marine acid, and afford algaroth pow der; and the remainder is not foluble in this menftruam, and is apparently vitrified.

From the preceding Synthetic experiments it appears, that by calcining together bone-afhes, that is, phosphorated lime, and antimony in a certain proportion, and afterwards expofing the mixture to a white heat, a compound was formed confifting of antimonial calx and phosphorated lime, in the fame proportion, and poffefling the fame kind of chemical properties, as James's powder."

The James's powder for horses seems to be Lile's powder not calcined.

The Pharmacopeia quoted is that of 1788, but the calcination with a while heat is only mentioned in the laît edition,

Art.

Art. XXII. An Account of fome Chemical Experiments on Tabafheer. By J. M. Macie, Efq. F. R. S.-The earth in this fubftance, and indeed in the whole body of the bamboo, feemned to be filiceous, or at least nearly refembling flint. This is a difcovery, we believe, wholly new; for the earth of vegetables, which was occafionally depofited in its proper form, was fuppofed to be exclufively lime.

'Since the above experiments were made, a fingular circum ftance has prefented itself. A green bamboo, cut in the hot-houfe of Dr. Pitcairn, at Iflington, was judged to contain tabasheer in one of its joints, from a rattling noife difcoverable on fhaking it, but being split by fir Jofeph Banks, it was found to contain, not ordinary tabafheer, but a folid pebble, about the fize of half a

pea.

Externally this pebble was of an irregular rounded form, of a dark-brown, or black colour. Internally it was reddish-brown, of a clofe dull texture, much like fome martial filiceous ftones. In one corner there were shining particles, which appeared to be crystals, but too minute to be diftinguished even with the microfcope.

This fubftance was fo hard as to cut glass.

A fragment of it expofed to the blow-pipe on the charcoal did. not grow white, contract in fize, melt, or undergo any change. Put into borax it did not diffolve, but loft its colour, and tinged the flux green. With foda it effervefced, and formed a round bead of opake black glafs.

Thefe two beads digefted in fome perfectly pure and white marine acid, only partially diffolved, and tinged this menftruum of a greenish yellow colour; and from this folution Prufsite of tartar, fo pure as not, under many hours, to produce a blue colour, with the above pure marine acid, inftantly threw down a very copious Pruffian blue.'

We trust that this fubject will be purfued; for the idea is only started, it is by no means properly examined.

Árt. XXIII. A fecond Paper on Hygrometry. By J. A. De Luc, Efq. F. R. S.-M. de Luc in this paper proceeds to the application of his former principles, and firft confiders the comparative obfervations between his own inftrument, made with flips of whalebone and M. Sauffure's. If his experiments refpecting the different hygrometrical properties of flips and threads are correct, M. Sauffure's inftrument must be irregular in its march, and erroneous in feveral of his points. M. de Luc very properly shows, what we had very early occafion to mention, that M. de Sauffure's point of extreme moisture is not correct. The maximum of evaporation is not fynonymous to the maximum of moisture; and these two expreflions may dif

U 4

fer

4

fer by, especially at a temperature of 75 or 80 degrees. Er rors of this kind are independent of hygrofcopic anomalies ow ing to the employment of threads, and various others would have occurred to him, our author tells us, if he had employed different fubftances. The conftruction of the inftrument feems alfo, from the account before us, to occafion fome irregularities, and the evaporating furface appeared to produce extreme moisture only to a limited extent. Our author's tables of the comparative marches of different fubftances are the result of much labour and accurate attention; his method of conftructing the inftrument can be understood only by a reader with the plate before him. We fhall conclude this last article, and our account of the volume, for nothing but the ufual lift of donors and donations remains, with M. de Luc's defcription of the properties of the whalebone as an hygrofcopic fubftance.

-

Steadiness is furely a firft requifite for fuch an inftrument; and in that respect no flip comes in competition with that of whale bone. That property was the first motive of my choice; and as an inftance of it I fhall only mention, that I have just now plunged into water an inftrument of that fort, of above ten years ftanding, which is come to its point of extreme meifture as if it had been fixed yesterday; for, without regard to the distance of obfervations, there may be between them a difference of fome tenths of a degree. Some other lips may be brought to a certain degree of feadiness by ftudying what is the degree of reach which they may bear; but that attention is not neceffary for the flip of whalebone if, for inftance, when its point of extreme moisture has been fixed while it was fretched to a certain degree, that fretch is much increased, it will acquire fome abfolute length; but it will be feady again for a new point taken then in quater.

Another property of the flip of whalebone, which at first should feem contradictory to the former, is its great expanfibility, in which alfo it furpaffes all the fubftances which I have tried. Such a flip lengthens above one-eighth of itself from extreme dryness to extreme moisture, which produces many advantages in the conftruction and obfervation of that inftrument. In respect to obfervation, when it is expofed to the wind, the difference between the chords of the arches of its bends and its real length is fo fmall comparatively with its hygrofcopic variations, that the indetermination of its index will remain confined in a space of one or two degrees, when it becomes impoffible to obferve hygrometers whofe fubftance has but little expansion. Lastly, of all the fubftances which I have reduced to flips, none is fo easily made thin and narrow as whalebone. I have found means for producing eafily fuch flips of it as, with a length of eight inches, weighs only about one-fixteenth of a grain, and are thereby as quick as is convenient in other refpects. All thofe dif

tinctive

native properties of the flip of whalebone seem to point out an hygroscopic fubftance fit for our common hygrometer.'

An Efay on Archery: defcribing the Practice of that Art, in all Ages and Nations. By Walter Michael Mofeley, Efq. 8vo. 75. Boards. Robfon. 1792.

THE hiftory of archery is, in fome degree, the history of human invention, relative to war, in the uncultivated ages. Its origin and progrefs, therefore, form at least a subject of amufement, to a philofophical, as well as a fuperficial reader. The author of the prefent Effay appears to have beftowed great pains in the collection of materials; and, in the application of them he likewife difcovers, not only much reading, but reflection. He begins with taking a short view of the different manners of nations, and points out the feveral degrees of eftimation the bow has commanded in the progrefs of fociety: proceeding afterwards to defcribe the gradual improvement of arms, with the advancement made by various nations in their construction, and the skill and dexterity fhewn in ufing them. The following reflections, in the profecution of the fubject, are ingeniously suggested :

As we fuppofe the principal ufe of thefe weapons, at firft, to be that of procuring food and cloathing, it will be asked, how it was poffible for a perfon, with no other affistance than a wooden fword, to accomplish the end proposed? I answer, that there are reasons which may induce us to think, that the cattle of the field were, in the early times of the world, tame, and almost without fear, as fome of them appear at prefent, (though to be fure these are not in a state of nature); and if fo, the difficulty of killing them would be little. Some writers haye fuppofed, that animals were originally wild, and fled the presence of man; but that having been taken when young, and ufed with gentleness, they became tame, and were reduced to the difcipline of the fhepherd. Others, as I have faid, maintain that all animals were primarily tame and gregarious; and that they became wild, in confequence of the purfuit of hunters endeavouring to take them for food. There are many curious facts recorded, which tend to fhew how gentle animals have been found in those parts of the world, little, or not at all inhabited. It is faid by Kempler, that in the Philippine Iflands the birds are fo tame as to be taken in the hand. In the Falkland Islands alfo, the geese may be knocked down with sticks. In Arabia Felix, the foxes fhew no figns of fear; and in an uninhabited island near Kamskatka, they scarcely turn out of a man's way.

If the latter opinion be true, (and it is as probable as the

former)

former) we fhall find no great difficulty in conceiving how a man armed with a wooden fword, might fupply himself with food and raiment. But this could not continue long. Experience would in a fort time teach the unfufpected flock to avoid the fight of him they at first beheld with indifference; and the cries of distress, and the fight of a fellow-creature struggling in the hands of a man, would raife a dread through the whole, which foon would be increafed to greater, and ftill greater degrees of fear. Recourfe muft then be had to millive weapons; and from this period, whenever it may have been, we may date the ufe of bows and ar

rows.

• I am inclined to think mankind, before this æra, must have toiled many an unfuccefsful hour amidit the woods in fearch of prey, because the contrivance of this inftrument appears to be complicated, and very unlikely to have been early invented. If we reflect upon this circumfiance, it will appear extraordinary how the idea of projecting a rod, in the manner a bow projects the ar row, first struck the mind of a savage.

• The inventions we find among thofe nations, who remain nearly in the fate of nature, appear in no inftance I can recollect, to be the refult of theory or á priori reafoning. Their devices are the cfforts of very feeble reafoning, and are commonly de duced from fome phænomenon presented to their view, among natural objects.

In order to illuftrate this obfervation, I fhall give wing to my fancy.

It is reasonable to think mankind would never have been tempted to venture on the fea, had not curiofity, or more proba bly the defire of food, been the motive. A favage (ignorant of all navigation) we will imagine, fitting on the beach endeavouring 10 take fish, perceives, that the further he throws his bait into the water, the greater his fuccefs. He is perfuaded therefore to walk in, and still finds his good luck to increase, as he advances in the deep water. Having proceeded to a confiderable distance, and as far as fafety permits him, let us fuppofe he fees a large fragment of wood, which in fome diftant country the wind has fevered from a tree, and the river and tide brought gently floating by his fide. Curiofity, or caprice, induces him to take hold of it; and finding that he receives fupport, he raifes himself upon it, and feels an unexpected pleafure in being carried with eafe and fafety to the fhore. Pleated and fatisfied with his adventure, he returns to his companions, who listen to his tale with furprise and admiration. He comes the next day to visit his ufual fishing-place, and defiring the fituation he was fo fuccefsful in before, looks for his favourite tree to carry him; but in vain :- the branch is floated to fome diftant place. Invention now awakes.-What must he do? 'Tis

obvious.