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rit of wine is highly rectified, the cold tube is to be fixed upon the bottle produced by it's evaporation is cer that contains the ether. When the tainly greater than when it is of the experiment is to be made, the stopper common fort; but the difference is of the bottle containing the ether is not so great as one who never tried removed, and the above-mentioned the experiment might expect. The tube is fixed upon it. The thread purer spirit produces the effect much round this tube should be moistened quicker.

a little with water or fpittle before it Uling various other fluids, which is fixed on the bottle, in order to prewere either compounds of water and vent more effectually any escape of spiritous substances, or pure essences, I ether between the neck of the bottle found that the cold produced by their and the tube. Then holding the bot. evaporation was generally in some in- tle by it's bottom, and keeping it intermediate degree between the cold clined, the small itream of ether ifluproduced by the water and that pro- ing out of the aperture of the tube is duced by the spirit of wire.

directed upon the ball of the thermoSpirit of turpentine brought the meter, or upon a tube containing wathermometer only 3 degrees lower ter or other liquor that is required to than the temperature of the room; be congealed. but olive oil and other oils, which Ether being very volatile, and havevaporate either very slowly or not at ing the remarkable property of inall, did not sensibly affect the ther- creasing the bulk of air, does not mometer.

require any aperture, through which Willing to observe how much elec- the air might enter the bottle, in protrization could increase the evapora- portion as the ether goes out: the heat tion of spirit of wine, and confequent- of the hand is more than sufficient to ly the cold produced by it, I put the force the ether in a stream from the tube containing the spirit into an in- aperture. sulating handle, and connected it After this manner, throwing the with the conductor of an electrical stream of ether upon the ball of a thermachine, which was kept in action mometer in such quantity as that a whilft the experiment was performed; drop of ether might now and then, by these means the thermometer was for instance every 10 seconds, fall brought down to 47 degrees. Hav- from the under part of the thermoing tried the three mineral acids, I meter, I have brought the mercury found that, instead of cooling, they down to 3 degrees, viz. 29 degrees heated the thermometer, which effect below the freezing point, when the I expected, since it is well known, atmosphere was somewhat hotter than that those acids attract the water from temperate, and that without blowing the atmosphere, and that heat is pro- upon the thermometer. duced by the combination of water When the ether is very good, viz. and any of them. The vitriolic acid, is capable of diffolving elastic gum, which was very strong and transpa- and the thermometer has a small bulb, rent, raised the thermometer to 102 not above twenty drops of ether are degrees; the smoaking nitrous acid required to produce this effect, and railed it to 72 degrees; and the ma, about two minutes of time; but when rine acid raised it to 66 degrees; the the ether is of the common fort, a temperature of the room, as well as of greater quantity of it, and a longer the acids, being 64 degrees, as men. time, are necessary to be employed, tioned above.

though at last the thermometer is The apparatus which I contrived brought down very nearly as low by for the purpose of using the least pos- this as by the best sort of ether. fible quantity of ether in freezing wa. In order to freeze water by the eva. ter, &c. confifts in a glass tube, termi. poration of ether, I take a thin glass nating in a capillary aperture, which tube about four inches long and about

one.

one-fifth of an inch in diameter, her- hotter: for instance, in the winter, the metically closed at one end, and put a water in the tube will freeze when the little water in it, so as to fill about half thermometer is about 30 degrees; but, an inch length of it. Into this tube in the summer, or even when the tema a slender wire is also introduced, the perature of the atmosphere is about 60 lower extremity of which is twisted in degrees, the quicksilver in the thermoa spiral manner, and serves to draw meter must be brought ten or fifteen, up the ice, when formed. Things or even more degrees below the freezbeing thus prepared, I hold the glass ing point, before the water which tube by it's upper part with the fingers surrounds the said thermometer will of the left-hand, and keep it conti

be converted into ice, even superfinually and gently turning round it's cially; hence it appears, that in the axis, first one way, and then the con- summer-time a greater quantity of trary; whilft with the right hand I ether and longer time are required to hold the phial containing the ether in freeze a given quantity of water than such a manner as to direct the stream in the winter, not only because then a of ether on the outside of the tube, greater degree of heat is to be overand a little above the surface of the come, but principally because in the water in it.

The capillary aperture summer a much greater degree of cold should be kept almost in contact with must be actually produced before the the surface of the tube that contains water that is kept in it will assume a the water. Continuing this opera- solid form. When the temperature tion for two or three minutes, the wa of the atmosphere has been about 40 ter will be froze as it were in an in- degrees, I have froze a quantity of ftant; since it will appear to become water with an equal weight of good opaque at the bottom, and the opa- ether; but at present, being summer, city will ascend in less than half a between two and three times the quansecond of time, which exhibits a beau. tity of the same ether must be used to tiful appearance. This congelation, produce the same effect. however, is only superficial, and in There seems to be something in the order to congeal the whole quantity air which, besides heat, interferes of water, the operation must be con with the freezing of water, and pertinued one or two minutes longer; haps of all Auids, though I cannot say after which the wire will be found to from experience whether the abovebe kept very tight by the ice. Now mentioned difference between the the bottle with the ether is left upon freezing of water in winter and fuma table or other place, and to the out mer, takes place with other fluids, side of the glass-tube the hand must as milk, and other animal fluids, oils, be applied for a moment, in order to wines, &c. soften the surface of the ice, which The proportion between the quanadheres very firmly to the glass, and tity of the ether and of the water that then pulling the wire out of the tube, may be frozen by it, seems to vary a solid and hard piece of ice will come according to the quantity of water; out, fastened to it's fpiral extremity. for a larger quantity of water seems

Instead of the wire, sometimes I put to require a proportionably less quan. a small thermometer into this tube fo tity of ether than a smaller quantity as to have it's bulb immersed in the of water, supposing that the water is water. With this thermometer I have contained in cylindrical glass vessels; observed a very remarkable phenome- for I have not tried whecher a metal non, which seems to be not explicable vessel instead of a glass one, and whein the present state of knowledge con ther some other shape befides the cycerning heat and cold. This is, that lindrical, might not facilitate 'the water will freeze in the winter with congelation. In the beginning of a less degree of cold than it will in the spring, I froze about a quarter of the summer, or when the weather is an ounce of water with nearly half an

2 X 2

ounce

ounce weight of ether, the apparatus down two degrees lower in the former being larger, though similar to that than in the latter case. described above.

As various persons may, perhaps, Now, as the price of ether, fuffici. be induced by this paper to repeat ently good for the purpose, is gene- such experiments, and as ether is a rally between eighteen-pence and two

fuid which can with difficulty be fhillings per ounce, it is plain that, preserved, it may be useful to menwith less than two shillings, a quarter tion, that'a cork confines ether in a of an ounce of ice, or ice-cream, may glass bottle much better than a glass be made in every climate, and at any itopple, which it is almost impossible time; which may afford great fatis to grind so well as entirely to prefaction to those persons who, living vent the evaporation of ether. When in places where no natural ice is to a stopple made very nicely out of a be had, never saw or tasted any sucho uniform and close piece of cork, delicious refreshments.

which goes rather tight, is put upon When a small piece of ice, for in a bottle of ether, the smell of that stance, of about ten grains in weight, fuid cannot be perceived through it; is wanted, the necessary apparatus is but I never saw a glass stopple that very small, and the expence of the could produce the same effeat. By ether not worth mentioning. I have opening the bottle very often, or by a small box, which is four inches and long keeping, the cork becomes loose, a half long, two inches broad, and in which cale it must be changed; and one inch and a half deep, which con thus, ether, spirit of wine, or any tains all the apparatus necessary for fuid, excepting those which corrode this purpose, viz. a bottle capable of cork, may be preserved. containing about one ounce of ether, I shall now describe a method of two pointed tubes, (in case that one purifying vitriolic ether, which is fhould break)a tube in which the water very easy and expeditious, though is to be frozen, and the wire. With not very profitable: Fill about a the quantity of ether contained in this quarter of a strong bottle with comsmall and very portable apparatus, mon ether, and upon it pour about the experiment, when carefully per- twice as much water, then stop the formed, may be repeated about ten bottle, and give it a shake, so as to times. A person who wishes to per

mix for a time the ether with the form such experiments in hotclimates,

This done, keep the bottle and in places where ice is not easily without motion, and with the mouth procured, requires only a large bot- downwards, till the ether is separattle of ether, besides the small appara- ed from the water, and swims over it, tus described above.

which requires not above three or It is a known fact, that the moment four minutes of time; then open the a quantity of water becomes ice, a bottle, and keeping it still inverted, thermometer kept immersed in it, let the greatest part of the water come rises a few degrees; and accordingly out very gently; after this the bottle this is observed in our experiment, being turned with the mouth upwards, viz. the mercury of the thermometer, more water must be poured in it, and which is immersed in the water of the in short the same operation must be tube, will suddenly rise, sometimes repeated three or four times. Lastly, as much as ten degrees, when the wa all the water being separated from the ter becomes first opaque. Electriza, ether by decanting it with dexterity, tion increases very little the degree of the ether will be found to be exceedcold produced by the evaporation of ingly pure. By this means I have pu. ether. Having thrown the electrifi. riñed common vitriolic ether, which ed, and also the unelectrified, stream could not affect elastic gum, and have of ether upon the bulb of a thermo- reduced it into such à fate as that meter, the mercury in it was brought elastic gum was easily diffolved by it.

Indeed,

water.

Indeed, this purified ether appeared and found that this empty thermomeby every trial to be purer than I ever ter was equal to 79,25 grains. This saw it, even when made after the best empty glass, previous to it's being usual method, and in the most careful weighed, was rendered as perfectly manner. The only inconvenience clean as possible, which is a necessary attending this process is, that a vast precaution in this experiment, which quantity of ether is loft. Not above depends upon a very great accuracy three or four ounces of a pound of of weight. Then I introduced fome common ether remain after the puri- mercury into the stem of this thermofication. As the greatest part of the meter, taking care that none of it enether is certainly mixed with the wa. tered the ball, and by adapting a scale ter that is used in the process, it may, of inches to the tube, observed that perhaps, be worth while to put that 4,3 inches length of the tube was fillwater into a retort, and to distil the ed with the mercury. The thermoether from it, which must come suffi. meter was now weighed again, and ciently pure for common use. from this weight, the weight of the

It is commonly believed, that wa- glass found before being subtracted, ter combines with the purest part of the remainder,viz. 0,24 grains shewed ether, when those two Huids are kept the weight of so much quicksilver as together; whereas, by the above de- filled 4,3 inches of the tube. Now fcribed process, the contrary is eita- the ball of the thermometer, and also blished: perhaps when ether is kept part of the tube, were entirely filled in contact with water for a long time, with quicksilver: then, in order to find the purest part of it may appear to be out the weight of the mercury con. loft, because the ether may be com- . tained in it, the thermometer was bined with, and may retain some wa- weighed for the last time, and from ter in itself, at the same time that the this weight the weight of the glass water combines with and retains fome being subtracted, the remainder, viz. ether;whereas the case may be diffe- 3205 grains, shewed the weight of the rent when the ether is quickly wash- whole quantity of quicksilver coned in water, and is immediately after tained in the thermometer. separated from it: but in respect to By comparison with a graduated this I have yet not made any experi. thermometer in hot and cold water, ments, so as to be able to decide the I made a scale to the new thermome

ter according to Fahrenheit's, and by applying a scale of inches found that the length of 20 degrees in this scale was equal to 1,33 inches. But

0,24 grains was the weight of so much The difficulty and uncertainty at- mercury as filled 4,3 inches length of tending the various methods hitherto the tube; therefore, by the rule of proposed for investigating the expan- proportion, it will be found that the fion of quicksilver, or it's increase of weight of so much quicksilver as fills bulk when rárified by a given degree 1,33 inches of the tube, viz. the length of heat, determined me to contrive of20 degrees, is equal to 0,0742 grains fome method by which this purpose nearly, and that the weight of so might be effected with more certainty much quicksilver as fills the length of and precision. After various expe- the tube that is equivalent to one riments, I hit upon the following me- degree, is equal to 0,00371 grains. thod, which to me seems both new and Now it is clear, that the weight of capable of great accuracy, though in the whole quantity of quicksilvercon. this I may be deceived.

tained in the thermometer is to the First, having blown.a ball to a ca- weight of so much quicksilver as fills pillary cube, such as are commonly the length of one degree in the tube, wred for thermometers, I weighed it, as the bulk of the whole quantity of

quicksilver

matter.

EXPERIMENTS RELATING TO THE

EXPANSION OF MERCURY.

quicksilver in a given degree of heat, increases the bulk of a quantity of to the increase of bulk that the same quicksilver of roobooths parts, viz. whole quantity of quicksilver acquires if the bulk of a quantity of quickfil. when heated of but i degree; viz. ver in the temperature of 50 degrees 32,05 grains is to 0,00371

grains, as is equal to 100,000 cubic inches, the I is to 0,0011+; so that, by this ex. bulk of the same quantity of quickperiment, it appears that I degree of silver in the temperature of 5ı degrees Fahrenheit's thermometer increa- will be equal to 100,000 cubic inches. ses the bulk of mercury not above

It is almost fuperfluous to mention, rodbogths parts. In this process, that the cavity of the tubes employed a small deviation from mathemati. for these experiments must be perfectcal exactness is occafioned by the ly uniform throughout. The scales small difference of weight between to be used for this method should be the quickfilver of the tube when first so exact as to be turned by the hun, weighed and when it is afterwards dredth part of a grain when charged heated to i degree; but by an easy with about half an ounce weight. calculation it will be found, that this

From these observations the method difference is so exceedingly small as of graduating, or of determining the not to be perceived by our exactest length of a degree in a new thermo, weighing and measuring instruments: meter, is easily deduced, the only re.

For clearness sake,Ishall subjoin the quisites for the calculation being the calculation of the above related expe- weight of a quantity of quicklilver, riments, disencumbered from words, which fills a known length of the tube; Here the decimals are not computed and the weight of the whole quantity to a very large number, that being of quicksilver contained in the ther. unneceflary for this purpose.

mometer when filled. Suppose, for

instance, that, in making a new therWeight of the glass, 79,25 grains. mometer, it be found that the weight Weight of so much

of so much quicksilver as fills five inquicksilver as fill.

ches length of the tube is equal to ten ed 4,3 inch.length

0,24 grains. grains, and that the weight of the of the tube,

whole quantity of quicksilver containWeight of the whole

ed in the thermometer weighs 300 quantity of quick

grains; it is plain that if the whole filver contained in $32,05 grains.

quantity of quicksilver weighs 300 the thermometer,

grains, roocooths parts of it will weigh Length of the tube

0,027 grains. But the weight of lo equal to 20 de

much mercury as fills five inches of grees,

the tube is equal to 10 grains; there4,3 : 0,24 :: 1,33 : 0,0742= fore, 0,027 grains weight of quickfil20 degrees

ver must fill 0,0133 inches of the tube, : 0,0742 :: : 0,00371

and this is equal to the length of 1 de 32,05 : 0,00371 :: 1 : 0,00011 gree, or the double, treble, &c. of it is += to the expansion occasioned by equal to two, three, &c. degrees. one degree of heat.

By this means the scale may be

made, that is, it may be divided into Having repeated this experiment degrees; but the numbers cannot be with other thermometers, and by fi. added to them without finding which milar calculations, each process gave of those degrees corresponds with the a result little different from the others, freezing pointor boiling point. Either which irregularity is certainly owing the point of boiling or freezing may to the imperfection of my scales, which be found by experiment, or any other are not of the nicest fort: but taking point may be afcertained by comparia mean of various experiments, it ap- son with another thermometer, and pears that i degree of heat, accord- then the other degrees are nominated ing to Fahrenheit's thermometer, accordingly.

DESCRIPTION

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1,33 inches.

200

I

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