I N K. 



well (hakcn, ami (llnvd witli a piec& of wire befare it is ufcd ; 

 if ii be too thick, it mull be diluted with a little oil of la- 

 \ .Jlt, oil of tuiper.tine, or alcohol. The faaility of .wri- 

 . :; with this compolition depends much on the quantity of/ 

 '.; ■ ^-.ilourins; matter. Nicholfon's Journnl, vol. ii. 8va. 

 ■'. j the duration of records, and other valuable writing?, 

 ■uls much on the goodnefs of the ink employed, Dr. 

 s has thought this fubjecl worthy of his attention. 

 . a. ciiicf imperfection of common inks is, that they decay in 

 I : r, and at lall the writing becomes invifible. From ex- 

 ; 1 in-.ents made by that autlior, he infers, that the dtxay of 

 ':■''■■■ ii chiefly owing to a deficiency of galls ; that the galls 

 •he moll pcrilhable iiijrredient, the quantity of tliefe, 

 !i gives the grcatell biacknefs at iirft (which is about 

 ■1 parts with the vitriol) being infufficient to maintain 

 ll. • colour ; that for a durable ink, the quantity of galls 

 cannot be much lefs than three times that of the vitriol ; that 

 it cannot be much greater without IcfTening tlie blacknefs of 

 tliv? ink ; that by diminilhing the quantity of water, the ink 

 V. 1 , rendered blacker and more durable ; that diflilled water, 

 r.v.n v,-atcr, and hard fpring-water, had the fame cffeds ; 

 That white wine produced a deeper black colour than water ; 

 tiiat the colour produced by vinegar was deeper than that by 

 wine ; that proof fpirit extracted only a reddifii-brown 

 tinge, and rectified fpirit a paler brown ; that the lafl men- 

 tioned tindlures funk into, and fpread upon the paper ; and 

 hence the impropriety of adding fpirit of wine to ink, as is 

 frequently directed, to prevent mouldinefs or freezing ; that 

 other aflringents, as oak bark, billort, floebark, S;c. were 

 not fb effeclnal as gall^, nor gave fo good a b'ack, the co- 

 lour produced by mod of thefe, excepting oak -bark, being 

 greenifh ; that tlie juice of floes did not produce a black 

 colour with martial vitriol ; but that, neverthek-fs, the 

 writing made with it became black, and was found to be 

 more durable than coir.mon ink ; that inks made with fatu- 

 rated folutions of iron in nitrous, marine, acetous acids, in 

 tartar, or in lem.on juice, were much inferior to the ink made 

 with martial vitriol ; that the colour of ink was depraved 

 by adding quicklime, which was done with an intention of 

 dellroying any fuperabundant acid which might be fuppofed 

 to be the caufe of the' lofs of the colour of thj ink ; that 

 the bell method of preventing the efffcls of this fuperabun- 

 dant acid is probably by adding pieces of iron to engage it ; 

 and that this conjeclure was confirmed by an inftaiice the 

 author had heard, of the great durability of the colour of 

 an ink in which pieces of iron had been long immerfed ; and 

 lalUy, that a decoction of logwood ufed inftcad of water, 

 fcuiibly improved both the beauty and deepnefs of the 

 black, without difpofing it to fade. The fame author ob- 

 ferves, that tlie addition of gum arabic is not only ufeful, by 

 keeping the colouring matter fufpended in the fluid, but alfo 

 by preventing the ink from fpreading, by which means a 

 greater quantity of it is collected on each itroke of the pen. 

 Sugar, which is fometimes added to inks, was found to be 

 much lefs effectual than gums, and to have the inconvenience 

 oj preventing the drying of the ink. The colour of ink is 

 found to, be greatly injured, by keeping tl.c ink in vcfll's 

 made of copper, or of lead, and probably of any othir 

 metal e>:cepting iron, which the vitriolic acid can diflolvc. 

 The foregoing experiments point out for the bell propor- 

 tions of the ingredients for ink ; one part of green vitriol, 

 one part of powdered logwood, and three pan^ of pow- 

 dered Aleppo, or blue galls. The bell meallruu™ appears 

 to be vinegar or white wine, though for conution ufe water 

 is fufficient. If the ink be required to be of a fu'l colour, a 

 quart, or at mod three pints, of liquor may be allowed to 

 ijjrcc ounces of jalh, and to one ounce of each of the 



other two ingredients. Half an otincf of gum may be 

 added to each pint of the liquor ; though the more gum we 

 can employ, confillently with due freedom of writing, it is 

 probable that the ink will be the more durable. The in- 

 gredients may be all piit together at once in a convenient 

 veflel, and well fliaken four or five times each day. In ten 

 or twelve days the ink will be fit for ufe, though it will im. 

 prove by remaining longer on the ingredients ; or it may be 

 made more cxpeditioudy, by adding the gum ard vitriol to 

 a decoction of galls and logwood in the menllruum. Ta 

 the ink, after it has been feparatcd from the foculencies, 

 fome coarfe powder of galls, froui which the fine dull has 

 been fiftcd, together with one or two pieces of iron, maybe 

 added, by which its durability will be fccured. 



It has been often remarked, fays tl;e fame ingenious 

 writer, that the inks ufed in former times were far more 

 durable than thofe of later years ; many modern records being 

 more decayed than manufcripts of mticli greater antiquity, 

 of which we have inftances in the Letters of Camillo Pa- 

 derni, puWifiied in the Philofophical Tranfadions for 175; 

 and 17)4. O""- Lewis made fevoral experiments, in order to 

 recover the compofition of this durable ink. Inllead of oil 

 which is ufed in the printers' ink, he mixed both lamp-black 

 and ivory -black with a folution of gum arabic ; this Jiquor 

 wrote of a fine black colour, but when dry, it rubbed ofF 

 entirely by moiiture. Concluding, therefore, that the co- 

 lour could no'i. be fufiicienlly *ixed on paper witliout an oily 

 cement, and as oils are made miicible with watery fluids by the 

 intervention of gimi, he mixed fome of the fofter printers' 

 varniili with about half its weight of a thick mucilage of gum 

 arabic, working them well together in a mortar, and beat 

 this mafs with lamp-black, adding water by little and little, 

 and continuing the rubbing, till the mixture became of a due 

 confillence for writing. This produced charafters of a full 

 brownifii black colour, which could not be difchargcd by 

 rubbing, nor walked out fo readily as the foregoing. Inftead 

 of the printers' varnifli, or boiled oil, linfeed-oil was mixed 

 in the fame manner with mucilage and lamp-black, and the 

 mixture diluted with water ; and the ink thus obtained was 

 much the fame as the other. To prevent the difcharge by 

 water, fome of the more finking kinds of paper, or common 

 paper made damp as for printing, mull be ufed, which will 

 admit the ink to fink a little into its fubltancc; and thus 

 tlic characters will be as fixed as can be defired. Such Dr. 

 Lewis found to be the ancient inks, that were fo durable, 

 Pliny and Vitruvius exprefsiy mention the preparation of foot, 

 or lamp-black, and the compofition of writing ink from 

 lamp-black and gum. Dioiceridcs fets down the propor- 

 tion of three ounces of the foot to one of gum. This mix- 

 ture was formed into cakes or rolls, and dried in the fun, 

 which were occafiojially tempered with water, as the Indian 

 ink is with us for painting. Theancionts were fcufible that 

 thefe inks wei-e liable to be difcharged by water, and cn- 

 deavourcd to obviate tliis impcrfediion, according to Pliny, 



iinKing 

 be dii". 



by ufing vinegar, inftead of water, for teniperin<r the mix- 

 ture of lamp black and gum, which promotes tlie " 

 into the paper. After all, noiie of thefe inks can 

 charged otherwifo than by dcfign ; which is the cafe with 

 refpedt to the vitriolic inks, and thofe of printed books and 

 copper-platos. 



In the courfe of Dr. Lewis's experiment!!, a farther im- 

 provenu'jit occurred to him, which was that of uiing the 

 common vitriolic ink, iiilleiKl of water, for tempering the 

 ancient mixture of gum and lamp-black. By this method 

 the writings will have the durability of thofe of former times, 

 with all the advaut.ige that refults from the vitriolic ink 

 fi.xing itlllf in the paper. Comuion writing ink may, in 

 R z many 



