Of the Instruments necessary for Operating upon Bodies in very high Temperatures.
SECT. I.
Of Fusion.
We have already seen, that, by aqueous solution, in which the particles of bodies are separated from each other, neither the solvent nor the body held in solution are at all decomposed; so that, whenever the cause of separation ceases, the particles reunite, and the saline substance recovers precisely the same appearance and properties it possessed before solution. Real solutions are produced by fire, or by introducing and accumulating a great quantity of caloric between the particles of bodies; and this species of solution in caloric is usually called fusion.
This operation is commonly performed in vessels called crucibles, which must necessarily be less fusible than the bodies they are intended to contain. Hence, in all ages, chemists have been extremely solicitous to procure crucibles of very refractory materials, or such as are capable of resisting a very high degree of heat. The best are made of very pure clay or of porcelain earth; whereas such as are made of clay mixed with calcareous or silicious earth are very fusible. All the crucibles made in the neighbourhood of Paris are of this kind, and consequently unfit for most chemical experiments. The Hessian crucibles are tolerably good; but the best are made of Limoges earth, which seems absolutely infusible. We have, in France, a great many clays very fit for making crucibles; such, for instance, is the kind used for making melting pots at the glass-manufactory of St Gobin.
Crucibles are made of various forms, according to the operations they are intended to perform. Several of the most common kinds are represented Pl. VII. Fig. 7. 8. 9. and 10. the one represented at Fig. 9. is almost shut at its mouth.
Though fusion may often take place without changing the nature of the fused body, this operation is frequently employed as a chemical means of decomposing and recompounding bodies. In this way all the metals are extracted from their ores; and, by this process, they are revivified, moulded, and alloyed with each other. By this process sand and alkali are combined to form glass, and by it likewise pastes, or coloured stones, enamels, &c. are formed.
The action of violent fire was much more frequently employed by the ancient chemists than it is in modern experiments. Since greater precision has been employed in philosophical researches, the humid has been preferred to the dry method of process, and fusion is seldom had recourse to until all the other means of analysis have failed.
SECT. II.
Of Furnaces.
These are instruments of most universal use in chemistry; and, as the success of a great number of experiments depends upon their being well or ill constructed, it is of great importance that a laboratory be well provided in this respect. A furnace is a kind of hollow cylindrical tower, sometimes widened above, Pl. XIII. Fig. 1. ABCD, which must have at least two lateral openings; one in its upper part F, which is the door of the fire-place, and one below, G, leading to the ash-hole. Between these the furnace is divided by a horizontal grate, intended for supporting the fewel, the situation of which is marked in the figure by the line HI. Though this be the least complicated of all the chemical furnaces, yet it is applicable to a great number of purposes. By it lead, tin, bismuth, and, in general, every substance which does not require a very strong fire, may be melted in crucibles; it will serve for metallic oxydations, for evaporatory vessels, and for sand-baths, as in Pl. III. Fig. 1. and 2. To render it proper for these purposes, several notches, m m m m, Pl. XIII. Fig. 1. are made in its upper edge, as otherwise any pan which might be placed over the fire would stop the passage of the air, and prevent the fewel from burning. This furnace can only produce a moderate degree of heat, because the quantity of charcoal it is capable of consuming is limited by the quantity of air which is allowed to pass through the opening G of the ash-hole. Its power might be considerably augmented by enlarging this opening, but then the great stream of air which is convenient for some operations might be hurtful in others; wherefore we must have furnaces of different forms, constructed for different purposes, in our laboratories: There ought especially to be several of the kind now described of different sizes.
The reverberatory furnace, Pl. XIII. Fig. 2. is perhaps more necessary. This, like the common furnace, is composed of the ash-hole HIKL, the fire-place KLMN, the laboratory MNOP, and the dome RRSS, with its funnel or chimney TTVV; and to this last several additional tubes may be adapted, according to the nature of the different experiments. The retort A is placed in the division called the laboratory, and supported by two bars of iron which run across the furnace, and its beak comes out at a round hole in the side of the furnace, one half of which is cut in the piece called the laboratory, and the other in the dome. In most of the ready made reverberatory furnaces which are sold by the potters at Paris, the openings both above and below are too small: These do not allow a sufficient volume of air to pass through; hence, as the quantity of charcoal consumed, or, what is much the same thing, the quantity of caloric disengaged, is nearly in proportion to the quantity of air which passes through the furnace, these furnaces do not produce a sufficient effect in a great number of experiments. To remedy this defect, there ought to be two openings GG to the ash-hole; one of these is shut up when only a moderate fire is required; and both are kept open when the strongest power of the furnace is to be exerted. The opening of the dome SS ought likewise to be considerably larger than is usually made.
It is of great importance not to employ retorts of too large size in proportion to the furnace, as a sufficient space ought always to be allowed for the passage of the air between the sides of the furnace and the vessel. The retort A in the figure is too small for the size of the furnace, yet I find it more easy to point out the error than to correct it. The intention of the dome is to oblige the flame and heat to surround and strike back or reverberate upon every part of the retort, whence the furnace gets the name of reverberatory. Without this circumstance the retort would only be heated in its bottom, the vapours raised from the contained substance would condense in the upper part, and a continual cohabitation would take place without any thing passing over into the receiver, but, by means of the dome, the retort is equally heated in every part, and the vapours being forced out, can only condense in the neck of the retort, or in the recipient.
To prevent the bottom of the retort from being either heated or coolled too suddenly, it is sometimes placed in a small sand-bath of baked clay, standing upon the cross bars of the furnace. Likewise, in many operations, the retorts are coated over with lutes, some of which are intended to preserve them from the too sudden influence of heat or of cold, while others are for sustaining the glass, or forming a kind of second retort, which supports the glass one during operations wherein the strength of the fire might soften it. The former is made of brick-clay with a little cow's hair beat up alongst with it, into a paste or mortar, and spread over the glass or stone retorts. The latter is made of pure clay and pounded stone-ware mixed together, and used in the same manner. This dries and hardens by the fire, so as to form a true supplementary retort capable of retaining the materials, if the glass retort below should crack or soften. But, in experiments which are intended for collecting gasses, this lute, being porous, is of no manner of use.
In a great many experiments wherein very violent fire is not required, the reverberatory furnace may be used as a melting one, by leaving out the piece called the laboratory, and placing the dome immediately upon the fire-place, as represented Pl. XIII. Fig. 3. The furnace represented in Fig. 4. is very convenient for fusions; it is composed of the fire-place and ash-hole ABD, without a door, and having a hole E, which receives the muzzle of a pair of bellows strongly luted on, and the dome ABGH, which ought to be rather lower than is represented in the figure. This furnace is not capable of producing a very strong heat, but is sufficient for ordinary operations, and may be readily moved to any part of the laboratory where it is wanted. Though these particular furnaces are very convenient, every laboratory must be provided with a forge furnace, having a good pair of bellows, or, what is more necessary, a powerful melting furnace. I shall describe the one I use, with the principles upon which it is constructed.
The air circulates in a furnace in consequence of being heated in its passage through the burning coals; it dilates, and, becoming lighter than the surrounding air, is forced to rise upwards by the pressure of the lateral columns of air, and is replaced by fresh air from all sides, especially from below. This circulation of air even takes place when coals are burnt in a common chaffing dish; but we can readily conceive, that, in a furnace open on all sides, the mass of air which passes, all other circumstances being equal, cannot be so great as when it is obliged to pass through a furnace in the shape of a hollow tower, like most of the chemical furnaces, and consequently, that the combustion must be more rapid in a furnace of this latter construction. Suppose, for instance, the furnace ABCDEF open above, and filled with burning coals, the force with which the air passes through the coals will be in proportion to the difference between the specific gravity of two columns equal to AC, the one of cold air without, and the other of heated air within the furnace. There must be some heated air above the opening AB, and the superior levity of this ought likewise to be taken into consideration; but, as this portion is continually coolled and carried off by the external air, it cannot produce any great effect.
But, if we add to this furnace a large hollow tube GHAB of the same diameter, which preserves the air which has been heated by the burning coals from being coolled and dispersed by the surrounding air, the difference of specific gravity which causes the circulation will then be between two columns equal to GC. Hence, if GC be three times the length of AC, the circulation will have treble force. This is upon the supposition that the air in GHCD is as much heated as what is contained in ABCD, which is not strictly the case, because the heat must decrease between AB and GH; but, as the air in GHAB is much warmer than the external air, it follows, that the addition of the tube must increase the rapidity of the stream of air, that a larger quantity must pass through the coals, and consequently that a greater degree of combustion must take place.
We must not, however, conclude from these principles, that the length of this tube ought to be indefinitely prolonged; for, since the heat of the air gradually diminishes in passing from AB to GH, even from the contact of the sides of the tube, if the tube were prolonged to a certain degree, we would at last come to a point where the specific gravity of the included air would be equal to the air without; and, in this case, as the cool air would no longer tend to rise upwards, it would become a gravitating mass, resisting the ascension of the air below. Besides, as this air, which has served for combustion, is necessarily mixed with carbonic acid gas, which is considerably heavier than common air, if the tube were made long enough, the air might at last approach so near to the temperature of the external air as even to gravitate downwards; hence we must conclude, that the length of the tube added to a furnace must have some limit beyond which it weakens, instead of strengthening the force of the fire.
From these reflections it follows, that the first foot of tube added to a furnace produces more effect than the sixth, and the sixth more than the tenth; but we have no data to ascertain at what height we ought to stop. This limit of useful addition is so much the farther in proportion as the materials of the tube are weaker conductors of heat, because the air will thereby be so much less coolled; hence baked earth is much to be preferred to plate iron. It would be even of consequence to make the tube double, and to fill the interval with rammed charcoal, which is one of the worst conductors of heat known; by this the refrigeration of the air will be retarded, and the rapidity of the stream of air consequently increased; and, by this means, the tube may be made so much the longer.
As the fire-place is the hottest part of a furnace, and the part where the air is most dilated in its passage, this part ought to be made with a considerable widening or belly. This is the more necessary, as it is intended to contain the charcoal and crucible, as well as for the passage of the air which supports, or rather produces the combustion; hence we only allow the interstices between the coals for the passage of the air.
From these principles my melting furnace is constructed, which I believe is at least equal in power to any hitherto made, though I by no means pretend that it possesses the greatest possible intensity that can be produced in chemical furnaces. The augmentation of the volume of air produced during its passage through a melting furnace not being hitherto ascertained from experiment, we are still unacquainted with the proportions which should exist between the inferior and superior apertures, and the absolute size of which these openings should be made is still less understood; hence data are wanting by which to proceed upon principle, and we can only accomplish the end in view by repeated trials.
This furnace, which, according to the above stated rules, is in form of an eliptical spheroid, is represented Pl. XIII. Fig. 6. ABCD; it is cut off at the two ends by two plains, which pass, perpendicular to the axis, through the foci of the elipse. From this shape it is capable of containing a considerable quantity of charcoal, while it leaves sufficient space in the intervals for the passage of the air. That no obstacle may oppose the free access of external air, it is perfectly open below, after the model of Mr Macquer's melting furnace, and stands upon an iron tripod. The grate is made of flat bars set on edge, and with considerable interstices. To the upper part is added a chimney, or tube, of baked earth, ABFG, about eighteen feet long, and almost half the diameter of the furnace. Though this furnace produces a greater heat than any hitherto employed by chemists, it is still susceptible of being considerably increased in power by the means already mentioned, the principal of which is to render the tube as bad a conductor of heat as possible, by making it double, and filling the interval with rammed charcoal.
When it is required to know if lead contains any mixture of gold or silver, it is heated in a strong fire in capsules of calcined bones, which are called cuppels. The lead is oxydated, becomes vitrified, and sinks into the substance of the cuppel, while the gold or silver, being incapable of oxydation, remain pure. As lead will not oxydate without free access of air, this operation cannot be performed in a crucible placed in the middle of the burning coals of a furnace, because the internal air, being mostly already reduced by the combustion into azotic and carbonic acid gas, is no longer fit for the oxydation of metals. It was therefore necessary to contrive a particular apparatus, in which the metal should be at the same time exposed to the influence of violent heat, and defended from contact with air rendered incombustible by its passage through burning coals. The furnace intended for answering this double purpose is called the cuppelling or essay furnace. It is usually made of a square form, as represented Pl. XIII. Fig. 8. and 10. having an ash-hole AABB, a fire-place BBCC, a laboratory CCDD, and a dome DDEE. The muffle or small oven of baked earth GH, Fig. 9. being placed in the laboratory of the furnace upon cross bars of iron, is adjusted to the opening GG, and luted with clay softened in water. The cuppels are placed in this oven or muffle, and charcoal is conveyed into the furnace through the openings of the dome and fire-place. The external air enters through the openings of the ash-hole for supporting the combustion, and escapes by the superior opening or chimney at EE; and air is admitted through the door of the muffle GG for oxydating the contained metal.
Very little reflection is sufficient to discover the erroneous principles upon which this furnace is constructed. When the opening GG is shut, the oxydation is produced slowly, and with difficulty, for want of air to carry it on; and, when this hole is open, the stream of cold air which is then admitted fixes the metal, and obstructs the process. These inconveniencies may be easily remedied, by constructing the muffle and furnace in such a manner that a stream of fresh external air should always play upon the surface of the metal, and this air should be made to pass through a pipe of clay kept continually red hot by the fire of the furnace. By this means the inside of the muffle will never be coolled, and processes will be finished in a few minutes, which at present require a considerable space of time.
Mr Sage remedies these inconveniencies in a different manner; he places the cuppel containing lead, alloyed with gold or silver, amongst the charcoal of an ordinary furnace, and covered by a small porcelain muffle; when the whole is sufficiently heated, he directs the blast of a common pair of hand-bellows upon the surface of the metal, and completes the cuppellation in this way with great ease and exactness.
SECT. III.
Of increasing the Action of Fire, by using Oxygen Gas instead of Atmospheric Air.
By means of large burning glasses, such as those of Tchirnausen and Mr de Trudaine, a degree of heat is obtained somewhat greater than has hitherto been produced in chemical furnaces, or even in the ovens of furnaces used for baking hard porcelain. But these instruments are extremely expensive, and do not even produce heat sufficient to melt crude platina; so that their advantages are by no means sufficient to compensate for the difficulty of procuring, and even of using them. Concave mirrors produce somewhat more effect than burning glasses of the same diameter, as is proved by the experiments of Messrs Macquer and Beaumé with the speculum of the Abbé Bouriot; but, as the direction of the reflected rays is necessarily from below upwards, the substance to be operated upon must be placed in the air without any support, which renders most chemical experiments impossible to be performed with this instrument.
For these reasons, I first endeavoured to employ oxygen gas for combustion, by filling large bladders with it, and making it pass through a tube capable of being shut by a stop-cock; and in this way I succeeded in causing it to support the combustion of lighted charcoal. The intensity of the heat produced, even in my first attempt, was so great as readily to melt a small quantity of crude platina. To the success of this attempt is owing the idea of the gazometer, described p. 308. et seq. which I substituted instead of the bladders; and, as we can give the oxygen gas any necessary degree of pressure, we can with this instrument keep up a continued stream, and give it even a very considerable force.
The only apparatus necessary for experiments of this kind consists of a small table ABCD, Pl. XII. Fig. 15, with a hole F, through which passes a tube of copper or silver, ending in a very small opening at G, and capable of being opened or shut by the stop-cock H. This tube is continued below the table at l m n o, and is connected with the interior cavity of the gazometer. When we mean to operate, a hole of a few lines deep must be made with a chizel in a piece of charcoal, into which the substance to be treated is laid; the charcoal is set on fire by means of a candle and blow-pipe, after which it is exposed to a rapid stream of oxygen gas from the extremity G of the tube FG.
This manner of operating can only be used with such bodies as can be placed, without inconvenience, in contact with charcoal, such as metals, simple earths, &c. But, for bodies whose elements have affinity to charcoal, and which are consequently decomposed by that substance, such as sulphats, phosphats, and most of the neutral salts, metallic glasses, enamels, &c. we must use a lamp, and make the stream of oxygen gas pass through its flame. For this purpose, we use the elbowed blow-pipe ST, instead of the bent one FG, employed with charcoal. The heat produced in this second manner is by no means so intense as in the former way, and is very difficultly made to melt platina. In this manner of operating with the lamp, the substances are placed in cuppels of calcined bones, or little cups of porcelain, or even in metallic dishes. If these last are sufficiently large, they do not melt, because, metals being good conductors of heat, the caloric spreads rapidly through the whole mass, so that none of its parts are very much heated.
In the Memoirs of the Academy for 1782, p. 476. and for 1783, p. 573. the series of experiments I have made with this apparatus may be seen at large. The following are some of the principal results.
1. Rock cristal, or pure silicious earth, is infusible, but becomes capable of being softened or fused when mixed with other substances.
2. Lime, magnesia, and barytes, are infusible, either when alone, or when combined together; but, especially lime, they assist the fusion of every other body.
3. Argill, or pure base of alum, is completely fusible per se into a very hard opake vitreous substance, which scratches glass like the precious stones.
4. All the compound earths and stones are readily fused into a brownish glass.
5. All the saline substances, even fixed alkali, are volatilized in a few seconds.
6. Gold, silver, and probably platina, are slowly volatilized without any particular phenomenon.
7. All other metallic substances, except mercury, become oxydated, though placed upon charcoal, and burn with different coloured flames, and at last dissipate altogether.
8. The metallic oxyds likewise all burn with flames. This seems to form a distinctive character for these substances, and even leads me to believe, as was suspected by Bergman, that barytes is a metallic oxyd, though we have not hitherto been able to obtain the metal in its pure or reguline state.
9. Some of the precious stones, as rubies, are capable of being softened and soldered together, without injuring their colour, or even diminishing their weights. The hyacinth, tho' almost equally fixed with the ruby, loses its colour very readily. The Saxon and Brasilian topaz, and the Brasilian ruby, lose their colour very quickly, and lose about a fifth of their weight, leaving a white earth, resembling white quartz, or unglazed china. The emerald, chrysolite, and garnet, are almost instantly melted into an opake and coloured glass.
10. The diamond presents a property peculiar to itself; it burns in the same manner with combustible bodies, and is entirely dissipated.
There is yet another manner of employing oxygen gas for considerably increasing the force of fire, by using it to blow a furnace. Mr Achard first conceived this idea; but the process he employed, by which he thought to dephlogisticate, as it is called, atmospheric air, or to deprive it of azotic gas, is absolutely unsatisfactory. I propose to construct a very simple furnace, for this purpose, of very refractory earth, similar to the one represented Pl. XIII. Fig. 4. but smaller in all its dimensions. It is to have two openings, as at E, through one of which the nozle of a pair of bellows is to pass, by which the heat is to be raised as high as possible with common air; after which, the stream of common air from the bellows being suddenly stopt, oxygen gas is to be admitted by a tube, at the other opening, communicating with a gazometer having the pressure of four or five inches of water. I can in this manner unite the oxygen gas from several gazometers, so as to make eight or nine cubical feet of gas pass through the furnace; and in this way I expect to produce a heat greatly more intense than any hitherto known. The upper orifice of the furnace must be carefully made of considerable dimensions, that the caloric produced may have free issue, lest the too sudden expansion of that highly elastic fluid should produce a dangerous explosion.
FINIS.
APPENDIX.
No. I.
TABLE for Converting Lines, or Twelfth Parts of an Inch, and Fractions of Lines, into Decimal Fractions of the Inch.
Twelfth Parts Decimal Decimal of a Line. Fractions. Lines. Fractions.
TABLE for Converting the Observed Heighths of Water in the Jars of the Pneumato-Chemical Apparatus, expressed in Inches and Decimals, into Corresponding Heighths of Mercury.
Note--Any degree, either higher or lower, than what is contained in the above Table, may be at any time converted, by remembering that one degree of Reaumeur's scale is equal to 2.25° of Fahrenheit; or it may be done without the Table by the following formula, R × 9 / 4 + 32 = F; that is, multiply the degree of Reaumeur by 9, divide the product by 4, to the quotient add 32, and the sum is the degree of Fahrenheit.--E.
No. V. ADDITIONAL.
RULES for converting French Weights and Measures into correspondent English Denominations.
§ 1. Weights.
The Paris pound, poids de mark of Charlemagne, contains 9216 Paris grains; it is divided into 16 ounces, each ounce into 8 gros, and each gros into 72 grains. It is equal to 7561 English Troy grains.
The English Troy pound of 12 ounces contains 5760 English Troy grains, and is equal to 7021 Paris grains.
The English averdupois pound of 16 ounces contains 7000 English Troy grains, and is equal to 8538 Paris grains.
To reduce Paris grs. to English Troy } grs. divide by } 1.2189 To reduce English Troy grs. to Paris } grs. multiply by }
To reduce Paris ounces to English }
Troy, divide by }
To reduce English Troy ounces to } 1.015734
Paris, multiply by }
Or the conversion may be made by means of the following Tables.
I. To reduce French to English Troy Weight.
The Paris pound = 7561 }
The ounce = 472.5625 } English.
The gros = 59.0703 } Troy.
The grain = .8194 } Grains.
II. To Reduce English Troy to Paris Weight.
The English Troy pound } = 7021. }
of 12 ounces } }
The Troy ounce = 585.0830 }
The dram of 60 grs. = 73.1353 } Paris
The penny weight, or } = 29.2540 } grains.
denier, of 24 grs. } }
The scruple, of 20 grs. = 24.3784 }
III. To Reduce English Averdupois to Paris Weight.
The averdupois pound of } }
16 ounces, or 7000 } = 8538. } Paris
Troy grains. } } grains.
The ounce = 533.6250 }
§ 2. Long and Cubical Measures.
To reduce Paris feet or inches into }
English, multiply by } 1.065977
English feet or inches into Paris, }
divide by }
To reduce Paris cubic feet or inches } to English, multiply by } English cubic feet or inches to Paris, } 1.211278 divide by }
Or by means of the following tables:
IV. To Reduce Paris Long Measure to English.
The Paris royal foot of } }
12 inches } = 12.7977 } English
The inch = 1.0659 }
The line, or 1/12 of an inch = .0888 } inches.
The 1/12 of a line = .0074 }
V. To Reduce English Long Measure to French.
The English foot = 11.2596 }
The inch = .9383 }
The 1/8 of an inch = .1173 } Paris inches.
The 1/10 = .0938 }
The line, or 1/12 = .0782 }
VI. To Reduce French Cube Measure to English.
The Paris } English { } cube foot = 1.211278 } cubical { 2093.088384 } The cubic } feet, { } inches. inch = .000700 } or { 1.211278 }
VII. To Reduce English Cube Measure to French.
The English cube foot, }
or 1728 cubical inches } = 1427.4864 } French
The cubical inch = .8260 } cubical
The cube tenth = .0008 } inches.
§ 3. Measure of Capacity.
The Paris pint contains 58.145 English cubical inches, and the English wine pint contains 28.85 cubical inches; or, the Paris pint contains 2.01508 English pints, and the English pint contains .49617 Paris pints; hence,
To reduce the Paris pint to the English, }
multiply by } 2.01508.
To reduce the English pint to the }
Paris, divide by }
No. VI.
TABLE of the Weights of the different Gasses, at 28 French inches, or 29.84 English inches barometrical pressure, and at 10° (54.5°) of temperature, expressed in English measure and English Troy weight.
Names of the Gasses. Weight of a Weight of a
cubical inch. cubical foot.
(A) qrs. oz. dr. qrs.
Atmospheric air .32112 1 1 15
Azotic gas .30064 1 0 39.5
Oxygen gas .34211 1 1 51
Hydrogen gas .02394 0 0 41.26
Carbonic acid gas .44108 1 4 41
(B)
Nitrous gas .37000 1 2 39
Ammoniacal gas .18515 0 5 19.73
Sulphurous acid gas .71580 2 4 38
No. VII.
Tables of the Specific Gravities of different bodies.
§ 1. Metallic Substances.
GOLD.
Pure gold of 24 carats melted but not hammered 19.2581 The same hammered 19.3617 Gold of the Parisian standard, 22 carats fine, not hammered(A) 17.4863 The same hammered 17.5894 Gold of the standard of French coin, 21-22/32 carats fine, not hammered 17.4022 The same coined 17.6474 Gold of the French trinket standard, 20 carats fine, not hammered 15.7090 The same hammered 15.7746
SILVER.
Pure or virgin silver, 24 deniers, not hammered 10.4743 The same hammered 10.5107 Silver of the Paris standard, 11 deniers 10 grains fine, not hammered(B) 10.1752 The same hammered 10.3765 Silver, standard of French coin, 10 deniers 21 grains fine, not hammered 10.0476 The same coined 10.4077
PLATINA.
Crude platina in grains 15.6017 The same, after being treated with muriatic acid 16.7521 Purified platina, not hammered 19.5000 The same hammered 20.3366 The same drawn into wire 21.0417 The same passed through rollers 22.0690
COPPER AND BRASS.
Copper, not hammered 7.7880 The same wire drawn 8.8785 Brass, not hammered 8.3958 The same wire drawn 8.5441
IRON AND STEEL.
Cast iron 7.2070 Bar iron, either screwed or not 7.7880 Steel neither tempered nor screwed 7.8331 Steel screwed but not tempered 7.8404 Steel tempered and screwed 7.8180 Steel tempered and not screwed 7.8163
TIN.
Pure tin from Cornwall melted and not screwed 7.2914 The same screwed 7.2994 Malacca tin, not screwed 7.2963 The same screwed 7.3065 Molten lead 11.3523 Molten zinc 7.1908 Molten bismuth 9.8227 Molten cobalt 7.8119 Molten arsenic 5.7633 Molten nickel 7.8070 Molten antimony 6.7021 Crude antimony 4.0643 Glass of antimony 4.9464 Molybdena 4.7385 Tungstein 6.0665 Mercury 13.5681
§ 2. Precious Stones.
White Oriental diamond 3.5212
Rose-coloured Oriental ditto 3.5310
Oriental ruby 4.2833
Spinell ditto 3.7600
Ballas ditto 3.6458
Brasillian ditto 3.5311
Oriental topas 4.0106
Ditto Pistachio ditto 4.0615
Brasillian ditto 3.5365
Saxon topas 3.5640
Ditto white ditto 3.5535
Oriental saphir 3.9941
Ditto white ditto 3.9911
Saphir of Puy 4.0769
Ditto of Brasil 3.1307
Girasol 4.0000
Ceylon jargon 4.4161
Hyacinth 3.6873
Vermillion 4.2299
Bohemian garnet 4.1888
Dodecahedral ditto 4.0627
Syrian ditto 4.0000
Volcanic ditto, with 24 sides 2.4684
Peruvian emerald 2.7755
Crysolite of the jewellers 2.7821
Ditto of Brasil 2.6923
Beryl, or Oriental aqua marine 3.5489
Occidental aqua marine 2.7227
§ 3. Silicious Stones.
Pure rock cristal of Madagascar 2.6530
Ditto of Brasil 2.6526
Ditto of Europe, or gelatinous 2.6548
Cristallized quartz 2.6546
Amorphous ditto 2.6471
Oriental agate 2.5901
Agate onyx 2.6375
Transparent calcedony 2.6640
Carnelian 2.6137
Sardonyx 2.6025
Prase 2.5805
Onyx pebble 2.6644
Pebble of Rennes 2.6538
White jade 2.9502
Green jade 2.9660
Red jasper 2.6612
Brown ditto 2.6911
Yellow ditto 2.7101
Violet ditto 2.7111
Gray ditto 2.7640
Jasponyx 2.8160
Black prismatic hexahedral schorl 3.3852
Black spary ditto 3.3852
Black amorphous schorl, called antique basaltes 2.9225
Paving stone 2.4158
Grind stone 2.1429
Cutler's stone 2.1113
Fountainbleau stone 2.5616
Scyth stone of Auvergne 2.5638
Ditto of Lorrain 2.5298
Mill stone 2.4835
White flint 2.5941
Blackish ditto 2.5817
§ 4. Various Stones, &c.
Opake green Italian serpentine, or gabro of the Florentines 2.4295 Coarse Briancon chalk 2.7274 Spanish chalk 2.7902 Foliated lapis ollaris of Dauphiny 2.7687 Ditto ditto from Sweden 2.8531 Muscovy talc 2.7917 Black mica 2.9004 Common schistus or slate 2.6718 New slate 2.8535 White rasor hone 2.8763 Black and white hone 3.1311 Rhombic or Iceland cristal 2.7151 Pyramidal calcareous spar 2.7141 Oriental or white antique alabaster 2.7302 Green Campan marble 2.7417 Red Campan marble 2.7242 White Carara marble 2.7168 White Parian marble 2.8376 Various kinds of calcareous stones } from 1.3864 used in France for building. } to 2.3902 Heavy spar 4.4300 White fluor 3.1555 Red ditto 3.1911 Green ditto 3.1817 Blue ditto 3.1688 Violet ditto 3.1757 Red scintilant zeolite from Edelfors 2.4868 White scintilant zeolite 2.0739 Cristallized zeolite 2.0833 Black pitch stone 2.0499 Yellow pitch stone 2.0860 Red ditto 2.6695 Blackish ditto 2.3191 Red porphyry 2.7651 Ditto of Dauphiny 2.7033 Green serpentine 2.8960 Black ditto of Dauphiny, called variolite 2.9339 Green ditto from Dauphiny 2.9883 Ophites 2.9722 Granitello 3.0626 Red Egyptian granite 2.6541 Beautiful red granite 2.7609 Granite of Girardmas 2.7163 Pumice stone .9145 Lapis obsidianus 2.3480 Pierre de Volvic 2.3205 Touch stone 2.4153 Basaltes from Giants Causeway 2.8642 Ditto prismatic from Auvergne 2.4153 Glass gall 2.8548 Bottle glass 2.7325 Green glass 2.6423 White glass 2.8922 St Gobin cristal 2.4882 Flint glass 3.3293 Borax glass 2.6070 Seves porcelain 2.1457 Limoges ditto 2.3410 China ditto 2.3847 Native sulphur 2.0332 Melted sulphur 1.9907 Hard peat 1.3290 Ambergrease .9263 Yellow transparent amber 1.0780
§ 5. Liquids.
Distilled water 1.0000 Rain water 1.0000 Filtered water of the Seine 1.00015 Arcueil water 1.00046 Avray water 1.00043 Sea water 1.0263 Water of the Dead Sea 1.2403 Burgundy wine .9915 Bourdeaux ditto .9939 Malmsey Madeira 1.0382 Red beer 1.0338 White ditto 1.0231 Cyder 1.0181 Highly rectified alkohol .8293 Common spirits of wine .8371
Heart of oak 60 years old 1.1700
Cork .2400
Elm trunk .6710
Ash ditto .8450
Beech .8520
Alder .8000
Maple .7550
Walnut .6710
Willow .5850
Linden .6040
Male fir .5500
Female ditto .4980
Poplar .3830
White Spanish ditto .5294
Apple tree .7930
Pear tree .6610
Quince tree .7050
Medlar .9440
Plumb tree .7850
Olive wood .9270
Cherry tree .7150
Filbert tree .6000
French box .9120
Dutch ditto 1.3280
Dutch yew .7880
Spanish ditto .8070
Spanish cypress .6440
American cedar .5608
Pomgranate tree 1.3540
Spanish mulberry tree .8970
Lignum vitae 1.3330
Orange tree .7050
Note--The numbers in the above Table, if the Decimal point be carried three figures farther to the right hand, nearly express the absolute weight of an English cube foot of each substance in averdupois ounces. See No. VIII. of the Appendix.--E.
No. VIII. ADDITIONAL.
RULES for Calculating the Absolute Gravity in English Troy Weight of a Cubic Foot and Inch, English Measure, of any Substance whose Specific Gravity is known.
In 1696, Mr Everard, balance-maker to the Exchequer, weighed before the Commissioners of the House of Commons 2145.6 cubical inches, by the Exchequer standard foot, of distilled water, at the temperature of 55° of Fahrenheit, and found it to weigh 1131 oz. 14 dts. Troy, of the Exchequer standard. The beam turned with 6 grs. when loaded with 30 pounds in each scale. Hence, supposing the pound averdupois to weigh 7000 grs. Troy, a cubic foot of water weighs 62-1/2 pounds averdupois, or 1000 ounces averdupois, wanting 106 grains Troy. And hence, if the specific gravity of water be called 1000, the proportional specific gravities of all other bodies will nearly express the number of averdupois ounces in a cubic foot. Or more accurately, supposing the specific gravity of water expressed by 1. and of all other bodies in proportional numbers, as the cubic foot of water weighs, at the above temperature, exactly 437489.4 grains Troy, and the cubic inch of water 253.175 grains, the absolute weight of a cubical foot or inch of any body in Troy grains may be found by multiplying their specific gravity by either of the above numbers respectively.
By Everard's experiment, and the proportions of the English and French foot, as established by the Royal Society and French Academy of Sciences, the following numbers are ascertained.
Paris grains in a Paris cube foot of water = 645511
English grains in a Paris cube foot of water = 529922
Paris grains in an English cube foot of water = 533247
English grains in an English cube foot of water = 437489.4
English grains in an English cube inch of water = 253.175
By an experiment of Picard with the measure and weight of the Chatelet, the Paris cube foot of water contains of Paris grains = 641326
By one of Du Hamel, made with great care = 641376
By Homberg = 641666
These show some uncertainty in measures or in weights; but the above computation from Everard's experiment may be relied on, because the comparison of the foot of England with that of France was made by the joint labours of the Royal Society of London and the French Academy of Sciences: It agrees likewise very nearly with the weight assigned by Mr Lavoisier, 70 Paris pounds to the cubical foot of water.
No. IX.
TABLES for Converting Ounces, Drams, and Grains, Troy, into Decimals of the Troy Pound of 12 Ounces, and for Converting Decimals of the Pound Troy into Ounces, &c.
TABLE of the English Cubical Inches and Decimals corresponding to a determinate Troy Weight of Distilled Water at the Temperature of 55°, calculated from Everard's experiment.
