are much the beft; the Iceland fishermen are fo fenfible of this, that they beat the bone upon a block with a thick ftick, till the pockets, as they term them, come out eafily, and thus preferve the found entire. If the founds have been cured with falt, that must be diffolved by steeping them in water, before they are prepared for ifinglafs; the fresh found muft then be laid upon a block of wood, whofe furface is a little elliptical, to the end of which a small hair brush is nailed, and with a faw-knife, the membranes on each fide of the found must be fcraped off. The knife is rubbed upon the brush occafionally, to clear its teeth; the pockets are cut open with fciffars, and perfectly cleanfed of the mucous matter with a coarse cloth; the founds are afterwards washed a few minutes in lime-water, in order to absorb their oily principle, and laftly in clear water. They are then laid upon nets, to dry in the air; but, if intended to resemble foreign ifinglafs, the founds of cod will only admit of that called book, but those of ling both fhapes. The thicker the founds are, the better the ifinglafs, colour excepted; but that is immaterial to the brewer,

who is its chief confumer.

This ifinglafs refolves into fining, like the other forts, in fubacid liquors, as ftale beer, cyder, old hock, &c. and in equal quantities produces fimilar effects upon turbid liquors, except that it falls speedier, and closer to the bottom of the veffel, as may be demonftrated in tall cylindrical glaffes; but foreign ifinglafs retains the confiftency of fining preferably in warm weather, owing to the greater tenacity of its native mucilage.

Vegetable acids are, in every refpect, beft adapted to fining: the mineral acids are too corrofive, and even infalubrious in common beverage.

It is remarkable that, during the converfion of ifinglafs into fining, the acidity of the menftruum seems greatly diminished, at leaft to tafte, not on account of any alkaline property in the ifinglafs, probably, but by its inveloping the acid particles. It is likewife reducible into jelly with alkaline liquors, which indeed are folvents of all animal matters; even cold lime-water diffolves it into a pulpous magma. Notwithftanding this is inadmiffible as fining, on account of the menftruum, it produces an admirable effect in other refpects: for, on commixture with compofitions of plafter, lime, &c. for ornamenting walls expofed to viciffitudes of weather, it adds firmnefs and permanency to the cement; and if common brick-mortar be worked up with this jelly, it foon becomes almost as hard as the brick itself: but, for this pur pofe, it is more commodiously pre pared, by diffolving it in cold water, acidulated with vitriolic acid; in which cafe, the acid quits the jelly, and forms with the lime a Jelenitic mafs, while, at the fame time, the jelly being deprived, in fome measure, of its moisture, through the formation of an indiffoluble concrete amongst its parts, foon dries, and hardens into a firm body; whence its fuperior strength and durability are easily comprehended.

It has long been a prevalent opinion, that furgeon, on account of its cartilaginous nature, would yield great quantities of ifinglafs but, on examination, na part of

this fish, except the inner coat of the found, promifed the leaft fuccefs. This being full of ruge, adheres fo firmly to the external membrane, which is ufelefs, that the labour of feparating them fuperfedes the advantage. The intef tines, however, which in the larger fifh extend feveral yards in length, being cleanfed from their mucus, and dried, were found furprizingly ftrong and elastic, refembling cords made with the intestines of other animals, commonly called cat-gut, and, from fome trials, promifed fuperior advantages, when applied to mechanic operations.

Having now fufficiently revealed the principal arcana in the manufacture of ifinglass, and explained fome of its leaft known phænomena and properties, the farther profecution thereof, as a commercial bufinefs, is left to others, whose future inquiries into the fubject, it is hoped, will, in fome refpect, be anticipated through this narrative; but whatever fuccefs may attend the attempt, I flatter myself to ftand acquitted, in having contributed every thing in my power to its advancement and perfection.

cularly of the Orchis latifolia, are found to anfwer almost equally well. This plant flourishes in various parts of Europe and Áfia, and grows in our country fpontaneously, and in great abundance. It is affiduously cultivated in the Eaft, and the root of it forms a confiderable part of the diet of the inhabitants of Turkey, Perfia, and Syria. A dry, and not very fertile foil, is beft adapted to its growth. An ingenious friend of mine, in order to collect the feed, tranfplanted a number of the Orchises into a meadow, where he had prepared a bed well manured for their reception. The next spring few of them appeared, and not one came to maturity, their roots being black and half rotten. The fame gentleman informed me, that he had never been able to raise any plant from the feed of the wild Orchis; but he ascribes his want of fuccefs to the wetness of the fituation in which he refides. I have now before me a feed-pod of the Orchis, the contents of which, to the naked eye, seem to be feed corrupted and turned to duft, but when viewed through a microscope, appear evidently to be organized, and would, I doubt not, with proper culture, germinate, and produce a thriving crop of plants. The propereft time for gathering the roots, is when the feed is formed, and the ftalk is ready to fall, because the new bulb, of which the falep is made, is then arrived to its full maturity, and may be diftinguished from the old one, by a white bud rifing from the top of it, which is the germ of the Orchis of the fucceeding year.

Several methods of preparing falep, have been propofed and practifed, Geoffroy has delivered a

very judicious procefs for this purpofe, in the Hiftoire de l'Academie Royale des Sciences, 1740; and Retzius, in the Swedish Tranfactions, 1764, has improved Geoffroy's method: but Mr. Moult, of Rochdale, has lately favoured the public with a new manner of curing the Orchis root; and as I have feen many specimens of his falep, at leaft equal, if not fuperior, to any brought from the Levant, I can recommend the following, which is his procefs, from my own knowledge of its fuccefs. The new root is to be washed in water, and the fine brown fkin which covers it is to be feparated by means of a small brush, or by dipping the root in hot water, and rubbing it with a coarfe linen cloth. When a fufficient number of roots have been thus cleaned, they are to be spread on a tin plate, and placed in an oven heated to the ufual degree, where they are to remain fix or ten minutes, in which time they will have loft their milky whitenefs, and acquired a tranfparency like horn, without any diminution of bulk. Being arrived at this ftate, they are to be removed, in order to dry and harden in the air, which will require several days to effect; or, by uĥing a very gentle heat, they may be finished in a few hours *.

Salep thus prepared, may be afforded in that part of England, where labour bears a high value, at about eight-pence or ten-pence per pound. And it might be fold till cheaper, if the Orchis were to

be cured, without feparating from it the brown fkin which covers it; a troublesome part of the process, and which does not contribute to render the root either more palatable or falutary: whereas the foreign falep is now fold at five or fix fhillings per pound.

The culture of the Orchis, therefore, is an object highly deferving of encouragement, from all the lovers of agriculture; and as the root, if introduced into common ufe, would furnish a cheap, wholefome, and moft nutritious article of diet, the growth of it would be fufficiently profitable to the far

mer.

Salep is faid to contain the greateft quantity of vegetable nourifhment in the fmalleft bulk. Hence a very judicious writer, to prevent the dreadful calamity of famine at fea, has lately propofed, that the powder of it fhould conftitute part of the provifions of every fhip's company. This powder and portable foup, diffolved in boiling water, form a rich thick jelly, capable of fupporting life for a confiderable length of time. An ounce of each of thefe articles, with two quarts of boiling water, will be fufficient fubfiftence for a man a day t and, as being a mixture of animal and vegetable food, muft prove more nourishing than double the quantity of rice cake, made by boiling rice in water; this laft, however, failors are often obliged folely to fubfift upon for feveral months, especially in voyages to

VOL, XVI.

Guinea,

Guinea, when the bread and flour are exhausted, and the beef and pork, having been falted in hot countries, are become unfit for ufe *.

But, as a wholefome nourishment, rice is much inferior to falep. I digefted feveral alimentary mixtures prepared of mutton and water, beat up with bread, fea-bifcuit, falep, rice, flour, fago powder, potatoe, old cheefe, &c. in a heat equal to that of the human body. In forty-eight hours they had all acquired a vinous fmell, and were in brisk fermentation, except the mixture with rice, which did not emit many air bubbles, and was but little changed. The third day feveral of the mixtures were fweet, and continued to ferment; others had loft their intestine motion, and were four; but the one which contained the rice was become putrid. From this experiment it appears that rice, as an aliment, is flow of fermentation, and a very weak corrector of putrefaction. It is, therefore, an improper diet for hospital patients; but more particularly for failors, in long voyages, because it is incapable of preventing, and will not contribute much to check the progrefs of that fatal difeafe, the fea-fcurvy †. Under certain circumftances rice feems difpofed of itself, without mixture, to become putrid; for, by long

keeping, it fometimes acquires an offenfive fœtor: nor can it be confidered as a very nutritive kind of food, on account of its difficult folubility in the ftomach. Experience confirms the truth of this conclufion; for it is obferved by the planters in the Weft-Indies, that the negroes grow thin, and are lefs able to work, whilft they subsist upon rice.

Salep has the fingular property of concealing the taste of falt-water; a circumftance of the highest importance at fea, where there is a fcarcity of fresh water. I diffolved a drachm and an half of common falt, in a pint of the mucilage of falep, fo liquid as to be potable, and the fame quantity in a pint of fpring-water. The falep was by no means disagreeable to the taste, but the water was rendered extremely unpalatable.

This experiment fuggested to me the trial of the Orchis-root as a corrector of acidity; a property which would render it a very useful diet for children: but the folution of it, when mixed with vinegar, feemed only to dilute, like an equal proportion of water, and not to cover its fharpness.

Salep, however, appears by my experiments to retard the acetous fermentation of milk, and, confequently, would be a good lithing for milk-pottage, especially in large

:

Vide Dr. Lind's Appendix.

towns,

towns, where the cattle being fed upon four draft, muft yield acescent milk.

Salep in a certain proportion, which I have not yet been able to afcertain, would be a very useful and profitable addition to bread. I directed one ounce of the powder to be diffolved in a quart of water, and the mucilage to be mixed with a fufficient quantity of flour, falt, and yeaft. The flour amounted to two pounds, the yeaft to two ounces, and the falt to eighty grains. The flour when baked was remarkably well fermented, and weighed three pounds two ounces. Another loaf, made with the fame quantity of flour, &c. weighed two pounds and twelve ounces; from which it appears, that the falep, though ufed in fo fmall a proportion, increased the gravity of the loaf fix ounces, by absorbing and retaining more water than the flour alone was capable of. Half a pound of flour, and an ounce of falep were mixed together, and the water added according to the ufual method of preparing bread. The loaf, when baked, weighed thirteen ounces and an half; and would probably have been heavier, if the falep had been previously diffolved in about a pint of water. But it fhould be remarked, that the quantity of flour

used in this trial, was not fufficient to conceal the peculiar tafle of the falep.

The restorative, mucilaginous, and demulcent qualities of the Orchis-root, render it of confiderable ufe in various diseases. In the feafcurvy it powerfully obtunds the acrimony of the fluids, and at the fame time is easily affimulated into a mild and nutritious chyle. In diarrhoes, and the dyfentery, it is highly ferviceable, by fheathing the internal coat of the inteftines, by abating irritation, and gently correcting putrefaction. In the fymptomatic fever, which arifes from the abforption of pus, from ulcers in the lungs, from wounds, or from amputation, falep ufed plentifully, is an admirable demulcent, and well adapted to refift that diffolution of the crafts of the blood, which is fo evident in these cafes. And by the fame mucilaginous quality, it is equally efficacious in the ftranguary, and dyfury; efpecially in the latter, when arifing from a venereal caufe, because the difcharge of urine is then attended with the most exquifite pain, from the ulcerations about the neck of the bladder, and through the course of the urethra. I have found it also an useful aliment for patients who labour under the ftone or gravel *.

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