IS^ , Improvement of Ink for writing. 



III. 



On certain ttfeful Properties of the Oxygenated Aluriatic Acid. By the Rev. ALEXANDER 



John FossrTH*. 



HE oxygenated muriatic acid has of late been employed with much fuccefs in the art of 

 bleaching and difcharging colour ; but I do not know that any one has hitherto obferved that- 

 its combinations with alkalies and earths, not only poflefles the property of difcharging colour, 

 but alfo of brightening and rendering many colours much more intenfe. 



As I hope that information on this fubjeft may be acceptable to fome of your readers, I 

 (hall give you an account of a few experiments made with the oxymuriate of carbonated pot- 

 afli with an intention not to difcharge, but to brighten colours. I preferred this fait, having 

 a conliderable quantity of it ready made, and from a few experiments tried with the 

 oxymuriates of carbonate of foda, foda, and lime, I thought they were more apt to difcharge 

 the colour, and feldom produced it fo clear as the former. Until very lately, I did not think 

 of making any experiments with the oxymuriate of ammoniac, but from thefe I am led to 

 fuppofe that it will have a ftill better efFedl than the oxymuriate of carbonated potafh. 



I difcovered this property of the oxymuriate of carbonated potafh by accident ; having 

 dropped a little of the aqueous folution of this fait upon clean writing-paper, when the paper 

 became dry, I was furprifed to fee my ink write much blacker where the faiine folution had 

 fpread, than any where elfe. I then fpread fome of the oxygenated muriatic acid upon the 

 fame paper, but here the ink became lighter coloured than ufual. I mixed a little ink in a 

 phial with clear water, and dropped into it a fmall quantity of the above faiine folution; at 

 firft, the ink became remarkably black, but whenever it had attained its greateft intenfity, the 

 very next drop, in fome degree, difcharged the colour. After many trials, being perfuaded 

 that this faiine folution when properly ufed would improve ink, I filled a quart bottle with the 

 thinnefl part of common ink poured off from the fediment, and made it as black as poflible 

 with this faiine folution. It has now flood without being moved for two months, has let fall 

 no precipitate, writes remarkably black (which to many people would be a very great 

 recommendation), flows eafily from the pen, and continues upon the paper much blacker than 

 any patent ink I have ever feen of the fame thicknefs: ink with little gum in it anfwers 

 beft, becaufe the faiine folution precipitates from gum a white fubftance, infoluble in water. 

 It is likewife proper, not to add fo much of the faiine folution as to make the ink perfectly 

 black all at once, for it improves by flanding in the bottle, and there is lefs danger of any of 

 the colour being difcharged. Of the faiine folution which I ufed, two drachms and forty 

 grains was fufficient for a quart bottle of ink, or one-fifth part of the weight of the fulphates 

 of iron and copper ufed in the compofition of the ink to be improved : this proportion occafions 

 no precipitation of the metallic oxids. 



* Communicated by the Author. 



Having 



