Another method of removing surface stains sometimes used by restorers is to cover the paper with a thin layer of fine powdered salt. Lemon juice is then squeezed on the surface in sufficient quantities to dissolve the mineral, and the subject finally washed in boiling water. The chief objection to this process is the use of hot water, which, as may well be imagined, is apt to pulp the paper, or in some cases even to efface the printed text.
Stains which cannot be removed by these processes are of several kinds. Lead pencil marks, for instance, will become fixed if the paper is damped, and they should therefore be helped out first of all with fine bread crumbs. Indian ink stains give way before a camel's hair brush and a cup of hot water, and all kinds of grease marks yield to benzine, turpentine, or ammonia.
Lead stains can be got rid of by an application of peroxide of hydrogen, or even hydrochloric acid; but the greatest care will have to be exercised in handling the latter, or it will corrode the paper in a very short time, causing it to crack and break to pieces. If mixed with its own weight of water, and to three parts of this compound one part of red oxide of lead is added, its power for evil will be very materially diminished; but even under these circumstances it is dangerous to use.
Each of these remedies has to be very carefully undertaken, as the fatty matters in the printer's ink are exceedingly liable to resolve, in which case the book will be spoiled. With care and attention I doubt not that almost any book can be very materially improved, if not made quite as good as new, by a combination of the processes described; and the best plan is to practise on some dirty and worthless specimen until the requisite degree of proficiency is attained.
A "Literary Note" in the magazine entitled Book Lore for July, 1887, observes as follows: "The renovation of books is, of course, a work of art in itself, and so clever are experts in the manipulation thereof, that many a dirty and decrepit volume has left their hands looking quite fresh and new. One of the most difficult processes has hitherto been to take dirt off the leaves without injuring the print. With this object bread crumbs were at one time used; but modern science has discovered three ways of effecting the same object in a much more satisfactory manner. Oxalic acid, citric acid, and tartaric acid, when in solution, will eliminate every trace of dirt without in any way acting on the printer's ink. Writing ink is not, however, proof against the attack of any one of the three, and this, too, being considered for the most part as 'dirt,' comes out with the rest. If the leaf is afterwards bleached with chloride of lime, the regenerating process is complete. The remedy for oil stains, it may be observed, is sulphuric ether. If the stains are extensive, it is best to roll up each leaf and insert it into a wide-mouthed bottle half full of ether, shaking it gently up and down for a minute or so. On its removal the oil marks will be found to have disappeared, and, as ether rapidly evaporates, a little cold water is all that is afterwards required. Mineral naphtha and benzoline each possess the property of dissolving oils fixed and volatile, tallow, lard, wax, and other substances of this class."
Worm-holes, another source of disquietude to the collector, are caused by grubs, which are popularly supposed to be the larvæ of beetles. They bore a circular hole through all the leaves, utterly destroying the appearance of any volume upon which they have fixed their attention.
The book worm has a pedigree in comparison with which the family tree of a Howard or a Talbot is a wretched weed. Lucian, in days remote, chides the voracious worm, and other ancient authors have called attention to its ravages. Another pest, called the "acarus," feeds on the paste and glue in the binding; in fact, these two parasites between them will very quickly digest the contents of an ordinary-sized book unless steps are taken for their destruction. The late Sir Thomas Phillipps, in a communication to the British Association in 1837, observes: "My library being much infested with insects, I have for some time turned my attention to the modes of destroying them, in the course of which I observed that the larva of certain kinds of beetles does not seek the paper for food, nor the leather, but the paste. To prevent their attacks, therefore, in future bound books the paste used should be mixed up with a solution of corrosive sublimate, or, indeed, with any other poisonous ingredient. But to catch the perfect insects themselves, I adopt the following plan: Anobium striatum commonly deposits its ova in beech wood, and is more partial, apparently, to that than any other wood. I have beech planks cut, and smear them over, in summer, with pure fresh paste (i.e., not containing anything poisonous). I then place them in different parts of the library where they are not likely to be disturbed; the beetles flying about the room in summer time readily discover these pieces of wood, and soon deposit their eggs in them. In winter (chiefly) the larva is produced, and about January, February, and March I discover what pieces of wood contain any larvæ by the sawdust lying under the planks, or where it is thrown up in hillocks on the top of them. All the wood which is attacked is then burnt for firewood: by this simple method I have nearly extirpated Anobia from my library."
To surprise and capture a book worm was at one time looked upon as an impossible task; but lately a few successes have been chronicled, but only a few. In order to ward off their insidious attacks, many devices more or less satisfactory have been proposed, but none appear to be absolutely preventative. Dr. Hermann, a noted bibliophile of Strassburg, after careful experiments, has come to the conclusion that a combination of safeguards such as he suggests will have the desired effect of putting to flight not only the worm itself but all other enemies of the library, always excepting biblioklepts and borrowers, against whom there is no defence. The combination suggested by Dr. Hermann certainly seems sufficiently powerful to resist almost any attack, in the same degree that a huge man-of-war may be considered invulnerable when exposed to the assaults of some cockle-shell of a boat. The only objection is the immense amount of trouble and labour involved in preparation, as will readily be perceived after a perusal of the preventives, ten in number.
1. Abolish the use of any wood in the binding processes. 2. Recommend the bookbinder to use glue mixed with alum in place of paste. 3. Brush all worm-eaten wood in the repositories of books with oil or lac varnish. 4. Preserve books bound in calf by brushing over with thin lac varnish. 5. No book to lie flat. 6. Papers, letters, documents, &c., may be preserved in drawers without any danger provided the wafers are cut out and that no paste, &c., is between them. 7. The bookbinder is not to use any woollen cloth, and to wax the thread. 8. Air and dust the books often. 9. Use laths separated one from the other one inch in place of shelves. 10. Brush over the insides of bookcases and the laths with lac varnish.
Dr. Hermann cannot at any rate be charged with any such sentimental regard for "vermin" as that which influenced Mr. Day, a well-known book hunter of the earlier part of the present century. One day, upon removing some books at the chambers of Sir William Jones, a large spider dropped upon the floor, upon which Sir William, with some warmth, said, "Kill that spider, Day! Kill that spider!" "No," said Mr. Day, with that coolness for which he was so conspicuous, "I will not kill that spider, Jones; I do not know that I have a right to do so. Suppose, when you are going in your carriage to Westminster Hall, a superior being, who perhaps may have as much power over you as you have over this insect, should say to his companion, 'Kill that lawyer! Kill that lawyer!' How should you like that? I am sure to most people a lawyer is a more noxious insect than a spider."