"_Loading._ Not more than 10 per cent. total mineral matter (ash).
"With regard to written documents, it must be evident that the proper materials are those of Class A, and that the paper should be pure, and sized with gelatine, and not with rosin. All imitations of high-class writing papers, which are, in fact, merely disguised printing papers, should be carefully avoided."
PASTES
To make paste for covering books, &c., take 2 oz. of flour, and oz. of powdered alum, and well mix with enough water to form a thin paste, taking care to break up any lumps. Add a pint of cold water, and heat gently in an enamelled saucepan. As it becomes warm, it should be stirred from time to time, and when it begins to boil it should be continually stirred for about five minutes. It should then form a thick paste that can be thinned with warm water. Of course any quantity can be made if the proportions are the same.
Paste for use is best kept in a wooden trough, called a "paste tub."
The paste tub will need to be cleaned out from time to time, and all fragments of dry paste removed. This can easily be done if it is left, overnight, filled with water. Before using, the paste should be well beaten up with a flat stick.
For pasting paper, it should have about the consistency and smoothness of cream; for leather, it can be thicker. For very thick leather a little thin glue may be added. Paste made with alum will keep about a fortnight, but can be kept longer by the addition of corrosive sublimate in the proportion of one part of corrosive sublimate to a thousand parts of paste. Corrosive sublimate, being a deadly poison, will prevent the attack of bookworms or other insects, but for the same reason must only be used by responsible people, and paste in which it is used must be kept out of the way of domestic animals.
Several makes of excellent prepared paste can be bought in London.
These pastes are as cheap as can be made, and keep good a long time.
Paste that has become sour should never be used, as there is danger that the products of its acid fermentation may injure the leather.
Paste tubs as sold often have an iron bar across them to wipe the brush on. This should be removed, and replaced by a piece of twisted cord. Paste brushes should be bound with string or zinc; copper or iron will stain the paste.
WHITE PASTE FOR MENDING
A good paste for mending is made from a teaspoonful of ordinary flour, two teaspoonsful of cornflour, half a teaspoonful of alum, and three ounces of water. These should be carefully mixed, breaking up all lumps, and then should be heated in a clean saucepan, and stirred all the time with a wooden or bone spoon. The paste should boil for about five minutes, but not too fast, or it will burn and turn brown.
Rice-flour or starch may be substituted for cornflour, and for very white paper the wheaten flour may be omitted. Ordinary paste is not nearly white enough for mending, and is apt to leave unsightly stains.
Cornflour paste may be used directly after it is made, and will keep good under ordinary circumstances for about a week. Directly it gets hard or goes watery, a new batch must be made.
GLUE
It is important for bookbinders that the glue used should be of good quality, and the best hide glue will be found to answer well. To prepare it for use, the glue should be broken up into small pieces and left to soak overnight in water. In the morning it should be soft and greatly swollen, but not melted, and can then be put in the glue-pot and gently simmered until it is fluid. It is then ready for use. Glue loses in quality by being frequently heated, so that it is well not to make a great quantity at a time. The glue-pot should be thoroughly cleaned out before new glue is put into it, and the old glue sticking round the sides taken out.
Glue should be used hot and not too thick. If it is stringy and difficult to work, it can be broken up by rapidly twisting the brush in the glue-pot. For paper the glue should be very thin and well worked up with the brush before using.
The following is quoted from "Chambers' Encyclopaedia" article on Glue:--
"While England does not excel in the manufacture, it is a recognised fact that Scottish glue ... ranks in the front of the glues of all countries. A light-coloured glue is not necessarily good, nor a dark-coloured glue necessarily bad. A bright, clear, claret colour is the natural colour of hide glue, which is the best and most economical.
"Light-coloured glues (as distinguished from gelatine) are made either from bones or sheepskins. The glue yielded by these materials cannot compare with the strength of that yielded by hides.
"A great quantity is now made in France and Germany from bones. It is got as a by-product in the manufacture of animal charcoal. Although beautiful to look at, it is found when used to be far inferior to Scottish hide glue."
PART II
CARE OF BOOKS WHEN BOUND
CHAPTER XXI
Injurious Influences to which Books are Subjected
_Gas Fumes._--The investigation of the Society of Arts Committee shows that--
"Of all the influences to which books are exposed in libraries, gas fumes--no doubt because of the sulphuric and sulphurous acid which they contain--are shown to be the most injurious."
The injurious effects of gas fumes on leather have been recognised for a long time, and gas is being, very generally, given up in libraries in consequence. If books must be kept where gas is used, they should not be put high up in the room, and great attention should be paid to ventilation. It is far better, where possible, to avoid the use of gas at all in libraries.
_Light._--The committee also report that "light, and especially direct sunlight and hot air, are shown to possess deleterious influences which had scarcely been suspected previously, and the importance of moderate temperature and thorough ventilation of libraries cannot be too much insisted on."
The action of light on leather has a disintegrating effect, very plainly seen when books have stood for long periods on shelves placed at right angles to windows. At Oxford and Cambridge and at the British Museum Library the same thing was noticed. The leather on that side, of the backs of books, next to the light, was absolutely rotten, crumbling to dust at the slightest friction, while at the side away from the light it was comparatively sound. Vellum bindings were even more affected than those of leather.
The committee advise that library windows exposed to the direct sunlight should be glazed with tinted glass.
"Some attempts have been made to determine the effect of light transmitted through glasses of different colours, and they point to the fact that blue and violet glass pass light of nearly as deleterious quality as white glass; while leathers under red, green, and yellow glasses were almost completely protected. There can be no doubt that the use of pale yellow or olive-green glass in library windows exposed to direct sunlight is desirable. A large number of experiments have been made on the tinted 'cathedral' glasses of Messrs. Pilkington Bros., Limited, with the result that Nos. 812 and 712 afforded almost complete protection during two months' exposure to sunlight, while Nos. 704 and 804 may be recommended where only very pale shades are permissible. The glasses employed were subjected to careful spectroscopic examination, and to colour-measurement by the tintometer, but neither were found to give precise indications as to the protective power of the glasses, which is no doubt due to the absorption of the violet, and especially of the invisible ultra-violet rays. An easy method of comparing glasses is to expose under them to sunlight the ordinary sensitised albumenised photographic paper.
Those glasses under which this is least darkened are also most protective to leather."
_Tobacco._--Smoking was found to be injurious, and it is certainly a mistake to allow it in libraries.
"The effect of ammonia vapour, and tobacco fumes, of which ammonia is one of the active ingredients, was also examined. The effect of ammonia fumes was very marked, darkening every description of leather, and it is known that in extreme cases it causes a rapid form of decay.
Tobacco smoke had a very similar darkening and deleterious effect (least marked in the case of sumach tanned leathers), and there can be no doubt that the deterioration of bindings in a library where smoking was permitted and the rooms much used, must have been partly due to this cause."
_Damp._--Books kept in damp places will develop mildew, and both leather and paper will be ruined.
Where possible, naturally dry rooms should be used for libraries, and if not naturally dry, every means possible should be taken to render them so. It will sometimes be found that the only way to keep the walls of an old house dry is to put in a proper dampcourse. There are various other methods employed, such as lining the walls with thin lead, or painting them inside and out with some waterproofing preparation: but as long as a wall remains in itself damp, it is doubtful if any of these things will permanently keep the damp from penetrating.
Bookshelves should never be put against the wall, nor the books on the floor. There should always be space for air to circulate on all sides of the bookshelves. Damp is specially injurious if books are kept behind closely-fitting doors. The doors of bookcases should be left open from time to time on warm days.
Should mildew make its appearance, the books should be taken out, dried and aired, and the bookshelves thoroughly cleaned. The cause of the damp should be sought for, and measures taken to remedy it.
Library windows should not be left open at night, nor during damp weather, but in warm fine weather the more ventilation there is, the better.
_Heat._--While damp is very injurious to books on account of the development of mildew, unduly hot dry air is almost as bad, causing leather to dry up and lose its flexibility. On this point the Chairman of the Society of Arts Committee says:--
"Rooms in which books are kept should not be subject to extremes, whether of heat or cold, of moisture or dryness. It may be said that the better adapted a room is for human occupation, the better for the books it contains. Damp is, of course, most mischievous, but over-dryness induced by heated air, especially when the pipes are in close proximity to the bookcases, is also very injurious."
_Dust._--Books should be taken from the shelves at least once a year, dusted and aired, and the bindings rubbed with a preservative.
To dust a book, it should be removed from the shelf, and without being opened, turned upside down and flicked with a feather duster. If a book with the dust on the top is held loosely in the hand, and dusted right way up, dust may fall between the leaves. Dusting should be done in warm, dry weather; and afterwards, the books may be stood on the table slightly open, to air, with their leaves loose. Before being returned to the shelves, the bindings should be lightly rubbed with some preservative preparation (see chap. XXII). Any bindings that are broken, or any leaves that are loose should be noted, and the books put on one side to be sent to the binder. It would be best when the library is large enough to warrant it, to employ a working bookbinder to do this work; such a man would be useful in many ways. He could stick on labels, repair bindings, and do many other odd jobs to keep the books in good repair.
A bookbinder could be kept fully employed, binding and repairing the books of a comparatively small library under the direction of the librarian.
BOOKWORMS