An Account of the Increase of Weight in Oyl of Vitriol Expos'd to the Air

An account of the increase of Weight in Oyl of Vitriol expos'd to the Air. Since the Excellent Mr. Boyle has made the Air a Subject of his Observations, the Learned World is sufficiently taught how vast a share it has in producing many effects, which Philosophy never so much as dream't of before; and if, upon the hint experiment has given us, we reflect on the infinite variety of steams constantly emitted from all sorts of Bodyes into the Atmosphere, which are there dissolv'd as it were in a common Menstruum; we have reason to expect therein particles enough of all shapes, sizes and motions fit and proper to alter the texture, diminish or increase the Bulk and weight, of almost any body expos'd to its action. As to the Increase of Weight (the business in hand) we know how bodies Rob'd of some constituent parts by fire (as quicklime and all calxes) slacken and greedily imbibe something from the Air; and the like is observ'd in the caput mortuum, of Salt, Nitre, Alum and Vitriol. On the same score all fixt Salts run into a fluid per diliquium; Tis the Air, that in seven years ful'y reimpregnates the earth heap't up in the shade whence Nitre was before extracted; tis the Air that causes the Efflorescence of Marcassites and Vitriol-stones; tis the Air that by its acid turns the lead of old buildings into Cerusse, which without doubt increases in Weight, (as that made by fire does) which is asserted to be at the rate of six or seven pound in an hundred. The same Growth of Metals seem to acknowledge the same origine, and there are none (Gold it self not excepted) but what Agricola, Gerhardus and some other Metallick Writers observe to have increas'd considerably by the free access of Air to the Shaft's and Grove's; and the very heaps of Rubbish wash't from Tin Oar's here in England have within the memory of man, nay in 10 or 12 years been wrought over again with great advantage: now though we must perhaps acknowledge in some of these Instances, that the particular seminal principle specifies these new acquir'd parts; and determinately makes them Mineral or Metallick of the name and nature of the Matrix into which they are received, yet this is certain; the addition of weight is owing to a Substance communicated by the Air. Instances of this nature concerning the growth of Lead, Iron, Tin, Silver and Gold with the Increase of other bodies are succinctly collected and with his wonted sagacity remarked by Mr Boyle in his tracts on that subject. So that the Increase and attractive power of Solids is a Theme already fairly cultivated and put beyond question: But that liquids such as seem Saturated with their own moisture should nevertheless imbibe more from the Air is not mentioned by any Author I know of, except the aforesaid Learned person, who in his Tract of Aerial magnets advices tryals upon the liquid preparations of Vitriol: I have heard indeed some Druggists have accidentally taken notice of this increase in Oyl of Vitriol, (and perhaps have improv'd it to their own gain though to the detriment of the buyer,) but the observation never was prosecuted with any method or certain account how much the said Increase was, and what the substance, gain'd. The Industrious Chymist Mr. VWhite our University Operator, having a Viol of that liquor unstop't and constantly running over, first gave occasion to the following notes: but since from thence no true estimate of the just Increase could be collected, I hope it may not prove altogether ungrateful to the Curious to give you, in answer to your request, what has occur'd more particularly on this subject, and I do it the more readily because the R.S. have thought it a thing not to little for the press. On the ninth of No. 1683. ThreeDrams of Oyl of Vitriol so far Dephlegm'd as to burn or Corrode a strong pack- thred assunder, was expos'd to the Air in a Marmalade Glass of three Inches Diameter, and plac't in a nice pair of Scales, in a Room where no fire nor Sun came; Its Increase for 7 natural days divided by less portions of time was according to the following Table. A TABLE | D. Hour | Gain | Space of time | Weath. | Wind. | Sum of gain. | Natural Day. | |---------|------|---------------|--------|-------|--------------|--------------| | 9 pom. | Dr. | o scr. o c r. | H. | South- | Dr. Scr. Gr. | 1st. | | 11 pom. | Gain | o scr. 19 | Moily. | ly. | 1 0 8 | | | 8 mat. | | | Moily & | N. We- | | | | 11 mat. | | | Windy, | sterly.| | | | 5 pom. | | | Rainy Morn. | Clear. | | | | 11 pom. | | | Starlight. | Cold. | Dr. Scr. Gr. | | | 8 mat. | | | Bright Morn. | mild. | | | | 11 mat. | | | Mild dry weather. | N. VV. | | | | 5 pom. | | | | | | | | 11 pom. | | | Mild dry | North. | Dr. Scr. Gr. | | | 8 mat. | | | clear Morn. | Frosty. | | | | 11 mat. | | | Overcast | N. more | | | | 5 pom. | | | | VVeast. | | | | 11 pom. | | | Cloudy Rain | VVeaster- | Scr. Gr. | | | 8 mat. | | | | ly. | | | | 11 mat. | | | Cloudy mild. | South- | | | | 5 pom. | | | | west. | | | | 11 pom. | | | Cloudy moist | South- | Scr. Gr. | | | 8 mat. | | | | east. | | | | 11 mat. | | | Cloudy misty | Souther- | | | | 5 pom. | | | Milty | ly. | | | | 11 pom. | | | Very Warm. | more South | Scr. Gr. | | | 8 mat. | | | | south East | | | | 11 mat. | | | | more South | | | | 5 pom. | | | | Easterly. | | | | 11 pom. | | | Cloudy unusually warm. | more South | Scr. Gr. | | | 8 mat. | | | | cloudy. | | | | 11 mat. | | | | Cloudy moist. | | | | 5 pom. | | | | Clear Coldish. | | | | 11 pom. | | | Dry Starlight | Easter- | Scr. Gr. | | | 9 mat. | | | | Cold. | | | | 11 mat. | | | Cloudy but Cold | South- | | | | 5 mat. | | | | Cloudy Windy | east. | | | | | | | Cloudy very wild. | | | From the 16th. in the successive spaces of twenty four hours, each gained one of the number of Grains following, as the 8th. natural day gain'd 13\(\frac{1}{2}\), the next 12, 9, 7, 6, 5, 5, 4\(\frac{1}{2}\), 3, 3, 3, 3, 4, 3. (December) 4, 4\(\frac{1}{2}\), 4, 3, 3, &c. still irregularly decreasing till the liquor was satiated. But these seven days, here specified in the Table, containing all the considerable variety to be observ'd in this business, it would be superfluous and impertinent to trouble the Reader with any longer Diary, which was kept to the 4th. of January 1681, when the Increase in 24 hours amounted scarce to half a grain, and probably had the weather been then dry, it might have been none at all, or rather the liquor might have lost what before it had gain'd; as I shall observe by and by to some other purpose. But what is obvious to discourse upon the whole, relates either to the Manner, Causes, Substance, Quantity and Time of the Increase, or to the Use that may be made of the experiment in order to the discovering of the changes in the Air. As to the first, the more our liquor was saturated, the less was its daily increase, though not gradually less by an even descent each day, but sometimes 2 or more natural days together it was exactly the same, a day or two after less and then again more the next day following according as the liquor stood affected by the heat or cold, dryness or moisture of the weather, the differing time of the day and quarter of the Wind. Thus upon the view of the whole Diary of almost two months; it appear'd, the increase was more in a Moist, Rainy, Misty, and Snowy, but less in a Frosty, Clear, and Dry Season, as also was more in a Cold than in a Warm Air. When the Wind was Northerly or Easterly the gain was less ceteris paribus than when Southerly or Westerly, and was less in the day than in the night. The primary cause of this Phenomenon seems to be the Moisture of the Air, which our liquor (a potential fire) im- imbibes as greedily, as actual fire does the pabulum of Nitre, yet we must allow that all the other Circumstances of Season just now mention'd have each their particular influences in diversifying the quantity of the Increase. Thus it appears in the Table that heat alters the progress of increasing: For on the fourteenth day of November from 11 mat. to 11 pom. (at which time specially towards night) a very unusual and troublesome heat in the Air was complain'd of by several here in Oxford; in twelve hours the gain was only three Grains and \(\frac{1}{2}\), whereas in the like time preceeding 'twas 10 Grains and \(\frac{1}{2}\), and in that just following 9 Grains. Neither indeed can any thing otherwise be expected from Heat, since thereby the Moisture might rather be exhal'd; or at least might be suspended, agitated and intimately mixt with the substance of the Air, and consequently not so easily be Arrested and Entangled by the surface of the Liquor, as when the Air is less hot. However allowing the effect of this anomalous accident at a time of the year when least expected, and considering that most commonly Heat keeps even pace with the Season of the year, depending as to its temper for the most part on the Nearness or Remoteness of the Sun; we may safely conclude Moisture the chief and only cause of the Increase of Weight in Oyl of Vitriol, since in Dry, Clear weather it constantly increases less than in Moist and Cloudy, the circumstance of Heat or Cold remaining the same in both. But this will be clearly evinced by an enquiry made into the nature of the substance gained, with the Increase of Weight. For by the ordinary ways of tryal it appeared the Atmosphere afforded our liquor nothing besides some of its watry particles, wherewith it always abounds, but more especially is ready to part with in Moist weather. The Air without doubt has great variety of different Substances floating in it, whereof some particles do ad- here to this, some other sort to that body, according as either is peculiarly dispos'd to receive one fort rather than another. Thus the Mortar in the Joints of old Walls and Vaults from Corpuscles attracted from the Air, Sprouts out and frames a peculiar kind of Salt. I have known a Deal Shelfe moisten'd only with the Liquor of fixt nitre, frosted over with Chrystal's of a perfect inflammable nitre by regaining the proper acid from the Air, all one as if so much Spirit of nitre had been pour'd on the said Liquor; I have seen a Viol half fill'd with Oyl of Tartar per deliquium (by being left open to the Air,) be set above the Liquor with peculiarly figur'd Crystalls, and at the bottom were flat Christaliz'd plates of a Salt which without flame crackled on a live Coal and left behind a Calx much like Dr. Lysters nitrum Calcarium. And tis well known Colcothar of Vitriol reimpregnated by the Air, will by a fresh distillation give you its proper Acid as at first. Now upon such hints as these, some (fond of the doctrine of Alcali and Acid) might perhaps expect, since differing Bodies of an Alcalizate nature do thus regain their proper acids, that vice versa even this most acid Liquor Oyl of Vitriol also might find its Alcalizate associate in the Air, from which the violence of fire had before driven it, but we could discover no such matter; the taff of our augmented Liquor was still purely acid and only weaker than before, whereas it would have been Saltish had an Alcali been combin'd with it, and its colour from a deep reddish, became limpid, all one as if the like quantity of fair water had been mixt; but to be more certain in this point I distill'd off the new gain'd Substance, at first it came over as insipid as clear water; and urging the fire farther, the drops prov'd sour, the remaining Oyl in the Retort was altogether as Corrosive as at first, whence we may infer its Edge was not at all blunted by any adjoyn'd Alcali; so that what the Air afforded was nothing else but meer water only. As As to the quantity of the whole Encrease it can't be determin'd by any general rule, since it varies according to the different Strength of the Oyl of Vitriol for it appears by the Table, the more diluted the Liquor, the less attractive it prov'd. This here employ'd (as highly Phlegm'd I presume as any usually is) gave a triple and more than \( \frac{1}{2} \) of its first weight, amounting in all from three to nine Drams, and thirty Grains before it come to a Stand. Which proportion of Encrease I found confirmed in lesser quantities also; as, three Grains Encreas't to more then nine Grains; and one Grain gave the weight of something more than three Grains. But besides the strength of the Liquor; there are other Circumstances, as the Season of the year; and position of the place, which will certainly something alter this point; thus our liquor will gain more in Winter than in Summer; more in a Cellar and Sunless Room, than in a Room not so qualified. All these circumstances which relate to the quantity will also influence very much the time of the Encrease, the last thing to be consider'd in the experiment; but I shall only mention that which makes the most peculiar and principal variation in this point, and 'tis the proportion of the Surface to the bulk of the Liquor. For I find the greater or less the Surface is, the quicker or slower the Encrease. Thus three Grains dropt and diffus'd to nere \( \frac{1}{4} \) Inch breadth on a peice of Glass, gain'd three Grains in six hours, one Grain in six more, one Grain and \( \frac{1}{2} \) in twelve hours more, in the next 12 hours gained \( \frac{1}{2} \) a Grain, and in the last twelve hours it gain'd very little observable; So that in less then forty eight hours, having more then triple its first weight, it was for some time fully satiated till Rainy weather added something more. But to discover more nicely what intrest the proportion tion of Surface has in hastening or retarding the increase of weight, I expos'd in the same Room and to the same temper of the Air (as near as I could Guess) three Drams of the same Oyl of Vitriol in an open flat Glass one Inch Broad, being only \( \frac{1}{4} \) of the Diameter of that Glass us'd at first with the like quantity. The result was this; that whereas the other Surface of three Inches Diameter gain'd (as in the Table) near nineteen Grains the first six hours, this less Surface gained a very little perceivable more than two grains in the same space of time. Now since the Area's of Circles are to one another as the squares of their respective diameters; as one the square of the less is to nine the square of the greater Glass's diameter; So was the weight of a little more than two Grains gain'd in the narrower Glass to near 19 Grains gain'd in the broader, wherefore the time of Increasing bears as near as can be expected an exact proportion to the Surface of the Liquor expos'd, and the liquor in the lesser Glass having but \( \frac{1}{4} \) part of the Surface of the greater, could not be satiated under nine times as many days as the greater. From what has been said it will also follow, that if this three Drams had a Surface in the same proportion to the weight of a Ruple and a Grain viz. a little more than six \( \frac{1}{4} \) Inches Diam. as that of 3 Inch was to three Grains, the Encrease of both would be finish't in the same time, and would excuse the long attendance of any that shall think it worth while to repeat the experiment. Perhaps too the different depth of the Glass together with the more or less free access of Air ought to be attended to in this affair: But thus much for the circumstances of the experiment. The only use of it I can at present find will be to estimate moisture and dryness in the Air which is evidently suggested by this following observation: That when the Oyl of Vitriol is satiated, in the moistest weather; it afterward retains or loses its acquired weight as the Air proves more or less moist. Thus the one grain above mention'd after its full increase often varied its equilibrium, viz. in dry weather, the weights, in moist, the liquor did constantly preponderate, and that so sensibly that the tongue of the Ballance of 1 ½ Inch long described an Arch of Variation to ¼ of an Inch compass; (which Arch would have been 2 ¾ Inches had the tongue been but one foot in length) even with that little quantity of Liquor, so that if more Liquor expanded under a large Surface be us'd, the minutest alteration of wheather must needs very much more affect it, and a bare pair of Scales will afford an Hygroscope as nice perhaps as any yet known. This Ballance may be contriv'd two ways, either such whose pin should be in the middle of the Beam, with a very slender tapering tongue of a foot or one foot and a half long, pointing to the divisions on a broad Arch'd plate fixt above in the handle according to figure the third in the Table; or else the Scale with the Liquor may be hung to a point of the Beam very near the pin, and the other extremum made so long as to mark a large Arch on a board plac'd conveniently for that purpose, as the fourth figure represents; The Scale in either may be a concave Glass of four or five Inch's Diameter. Lastly, on the division of the Arches should be inscrib'd the different temperature of the Air shewn by the Liquor. The fifth Figure gives the lineament of another Hygroscope made of a Viol-string running upon pulleys, and suspending a bullet fixt to the shorter end of an Index, whose other extremity is so long as to describe a long Arch by the falling and rising of the Bullet upon the Stretching and Shrinking of the String which which would be more nice, were the Index fastened to the center of the last pully. An experiment very obvi- ous, but not taken notice of (as I know) by any writer, and so I thought it not impertinent to be mention'd here among Hygroscopes. But tis high time to conclude. I shall only add this advertisement that whereas in this experiment only Oyl of Vitriol was employ'd, I have rea- son to think that Oyl of Sulphur per Campanam, as also Oyl of Tartar per deliquium, and the Liquor of Fixt Nitre &c. may succeed as well; however, Sir, I must leave the prosecution and improvement of this and such like observations to persons who have better instruments and more leisure for such matters than, Your humble Servant. W. G.