P. 74.

Mr. URBAN,

IN

W. & D.

and

April 20. N Vol. LXII. p. 1178, you gave a place to my paper of objections to Dr. Harrington's theory *; to which, B. H hath made a reply; calling himfelf a third body, neceifers to the Plu mination of the fubje&t: he con pares himself, as that third body, to all, nor improperly; for all his replications are light and unfubft-ntial as air ticit. B. Heems very defous of myn.me being affixed to my, objections. In what refped can a name either add to, or fubtract trom, the force of an argu ment? were mine nes effary, I would not withhold it; but, as it is not. I think proper, at prefent, to ufe a fictitious fig. nature in its place.

You, your felf, Mr. Urban, and many of f your readers, are well convinced that all B. H's fee-faw, defu.tore observations have not, in the leaf, removed the objections I offered: they are not applied to them; nor are they, by any means, calculated to remove them. And it is by no means an argument in favour of B. H's principies, that, by way of removing an objection, he wonders from one thing to another, and talks about every thing, but the obje&ion to be removed.

B. H. fays, that the arguments which I draw from vitriolated tartar, and felenite, are foreign to the question how combustion is conducted;-but, why are they foreign to the question? A bare allertion proves nothing, unlets it be that reatons are wasting. Thole arguments are not foreign to the laws of nature: they are not foreign to what in reality does take place in combustion: but they are repugnant to Dr theory; therefore, that theory is inconfiftent with nature, and abluid; other wife, nature is inconfitient with herteif.

H's

B. H. then, instead of anfwering my objections, employs himielt in again repeating Dr. H's theory, and in trifling about the brit accention of a ipark. He then, childishly, entertains himself with thinking what a rare baze that Spark would make, were it to fall upon a heap of combuftioles, as large as St. Paul's cathedral :-ridiculous nonfente! -pitiful evanon !-but he ful makes not one atten.pt to explain why the fixed fire in air, or the concentrated pre in

*P. 1179, for "forms," r. "terms,"

ite, ale; but, be ng brought togethele.cnfined fire of one will, then, Liberate if and the o’ber also.

Wir relpet to my queftion, of what idea we are to form of the ftate in which fire exils, when furrounding a particle of mild acid, fo as to form a panicle of air; in which flate, as very Inttle of the fire can be in contact with the acid particle, how are those igneous particles, fur difast from the acid, infuenced, and fixed by it; fo, as to be deprived of all their effential properties, as fie? B. H. fays, fire faturates the delicate acid of fixed air, in the fame onder that Kili faturates the vitrioc and in vitro.ated tartar. This is only reading to the difficulty, without explaining it; vitriolic acid will not Ja u ate mor Kei than comes in contact into cole combination with it, it will fill semain Kal; not neutralized, nor in any respect altered in its properties: but the delicate acid of air, when feparated by fire, from its combination with mercury, for inftance, by the quantity of fie it is faid to attract and heurize is changed, a folid, into an der form fluid. In this aëtorm ftate the particies of this delicate acid muft each be tu rounded by a very extensive atz ofphere of fire; a very mali propor tion of which only can be in contact with the acid particles; and, confequently, the greatest part of that fire is very far difiant from the acid particles it urrounds. The quefhios, therefore, is,

how does the acid particle in the centre of a particle of air, act upon the atmosphere of fire widely extended around it, fo as 10 fix it there, and deprive it of all its igneous properties? It cannot be by any chemical attraction; because, chemical affinities only take place when the particles are in contal; therefore, the mild acid cannot, chemically, neutraitze more fire than it is in contact with; and the inactive state of the oiber part of the atmosphere of fire remains to be explained and accounted for. In fact, the doctrine of all Gafes, airing the aëriform states to atmospheres of tire, furrounding their component particles, is perfectly unphilofophical, and cannot be, rationally, explained, either by Dr. Harrington or M. Lavo fier, whole fyftems are, therefore, cqnany abiurd,

B ti. then very liberally queftions my chemical knowledge, without any data upon which to form his doubts.

He

He fays, that antimory, faturated with fire, is mild: when calcined to a certain degree, it becomes cauftic, and active, by part of its fire being separated: but, when heated by the full force of the actual fire of a furnace, it again becomes mild, by being deprived of its fire, in a fill greater degree, by the heat of the furnace. I am chemift enough, however, to fee, that it is a very abfurd method of depriving a body of its fire, to put it into the frongef fire, we can, conveniently, meet with; which is vaftly like plunging a man into the river, by way of drying a damp fhirt: and, confequently, I am too much of a chemift to fit down contented with fuch explanations and inconfiftencies as Dr. H's theory abounds with.

The number of opinions, which have been promulgated, adopted, and then rejected, fufficiently prove that the moft powerful minds may be even fatisfied with error, 'till it is detected: confequently, Dr. H's principles, being erro neous, by no means detract from his abilities he is a man-and, “huma num eft errare." But, if he will, with a mind divefted of all partiality, duly confider the obje&ions above recited, he will, I am fure, candidly give up his principles. If he does not, I am cer tain of this, that he either wants abili ties to comprehend the force of thofe objections, which I do not think is the cafe; otherwife, he does not poffefs that unprejudiced and truly philofophic mind, which, immediately, owns conviction, when it feels the influence of TRUTH.

Mr. URBAN,

May 8,

THANKS aie due from me to an Eastern Botanist, p. 331, on four feveral accounts, and I render them on each with particular fatisfaction; he has prevented the continuance of my error refpecting the peduncle of the kneeholly, and has faved me from misleading many of your readers. I am obliged to him for his flattering approbation of my communications, and for the amufement derived from his directions. My eye had deceived me, and the " Alphabet of Plants" had confirmed the deception, the compiler of that work faying exprefsly, the flowers grow on the middle of the upper furfage of the leaves."

Swallows appeared here on April 22, and were coupling on the d of the prefent month.

In general, the ftudy of Natural Hiftory enlarges the mind; but I am forry to remark, that it does not feem to have that effect on the perfon who is defi rous of receiving communicatory letters concerning the Dolphin Butterfly, vol. LXII. p. 688. If he will break his difobliging filence, and give the defcription defired by Mr. Lafkey, p. 1106, he may poffibly hear of the infect this year, if it is indigenous; as butterflies are again numerous. People who have directed their attention to Entomology only, it is true, would know it without that aid; but it is as likely to be feen by me, or by any other general obferver of Nature, as by profeffed Entomologifts. A SOUTHERN FAUNIST.

Mr. URBAN,

King's Coll. Cam. May 15. THE conjurer of Chalgrave's Fern having much excited the curiofity of the publick, I shall be glad through your means to inform your Botanical correfpondents, that I have found the plant this fpring, in great abundance, in Madingley Wood, near Cambridge. It appears to me, from repeated exami nations, in all its different states, to be Acidium Fufcum. Lin. Syn. Nat. Gmelin, p. 1473. It is paralitical on the leaves, and fometimes, though rarely, on the petals of Anemone Nemorofa. I fhail, in a few days, publish a defcription of it in a third Supplement to my "Flora Cantabrigienfis;" and intend, in a fhort time, in a separate publication, to give the full hiftory of the plant, illuftrated by coloured plates. In the mean time, 1 fhall be happy, upon an application being made to me by letter, to fend twenty fpecimens of the plant, if fo many of your correfpondents inform me that they will be acceptable; having ever efteemed the giv ing away of a curious plant the fecond pleasure to the original discovery.

Yours, &c. 'R. RELHAN.

plough, have excited the industry and ingenuity of our numerous inhabitants, to improve every article of manufacture. In this they were encouraged by the plenty of fire and water, diftributed through every part of the island. Henry VII happily laid the foundation of our happinefs, by reducing the tyrannical power of our peers, and thereby gave the induftrious an opportunity to purchafe real property. Commerce having thereby increafed greatly in the reign of his grand-daughter, during her reign the Commons began to acquire wealth; and, as power conftantly accompanies wealth, the House of Commons began to claim what their wealth entitled them to: that commerce continuing, the power of the Commons fecures to us the continuance of liberty. M. Colbert, faid to be one of the beft minifters France was ever happy in governing, has probably laid the foundation of that Revolution which has lately happened: for, having encouraged commerce to the utmost of his power, he brought thereby great wealth into the hands of the Tower rank of people; and thus they got the better of their proud but poor arif

tocrates.

On taking a view of this country, a judicious obferver may foon difcover, that it may be divided into the rich foil of the champain parts well adapted to the plough, and into the light and dry foils frequent on the declivities of rifing grounds. The latter is proper for the pafture of our flocks of theep, which yield us the article that laid the foundation of our prefent flourishing fate. The improvement of wool deferves our utmost attention, and fha!! be the fub ject of this paper, in which I fhall only attempt to add fome hints to what the indefatigable industry and zeal of that moft worthy patron Sir John Sinclair, Baronet, has occafionally published.

By the prefent management of our fheep, it is found, that the carcafes are inore valuable to the farmer than the fleece. It cannot be expected that he will forget his advantage; and on this account it will be highly neceffary, that every means fhould be ufed to render the fleece nearly of an equal value with the carcafe. It is well known that fucculent food enlarges the carcafe, at the fame time rendering the wool of a longer and coarfer ftaple. This must be the confequence of the sheep feeding on turnips and clover, which are both very fucculent. It would hence be proper,

that we should as much as poffible feed our theep on fuch plants as, at the fame time that they nourish, are yet of a warmer quality, and do not yield fo much of a watery juice. This is a pur fuit that must be afcertained by experiments; and I therefore think, that it is an cbje deferving the attention of the fociety inflituted for the improvement of British wool, who might offer premiums for fuch experiments.

Experiments in feveral parts of England have incontestably proved that fainfoin yields more pafture on dry foils than any other plant for pafture (lucerne excepted). It thrives beft on a fouthern alpect. The feed may be fown in April, fix bufhels to the acre. As it is a tap-rooted plant, and flourishes for years, it is more advisable to rear it in a nursery, and tranfplant in Auguft, in rows 6 inches afunder, the plants growing 4 inches afunder, in which manner it is more easily weeded, and the plant has room to grow to a proper fize. Common grafs should not be permitted to grow among it. It may be fed with lambs during the autumn, which must be taken off before the rams' hair renders the earth pouchy, or the tender tops of the plants be injured. For the fame reafon, large cattle should not be admitted in rainy weather till the plants have attained their full ftrength : It fattens fheep fooner than any other plant, and therefore may be expected to improve the wool. If it is intended to eat it for hay, and the feafon proves rainy, it is better that it remains ftanding, for then the feed will ripen, and make up for the time loft in making the hay. If keep are fed on this hay, it fhould be cut with a chaff-cutter. it hoots early, and it injures the crop to cut off the bud, it should not be fed too early. Saintfoin, though lefs in quantity on a dry foil, is more nourishing in proportion to the quantity than what grows on a rich foil." It does not well bear fhade, and therefore trees should not be planted in the furrounding hedges. The foil cannot be ploughed too deep where it is to be raifed.

As