NA TURE 



[January 4, 1906 



than were contained in the appendices to the original 

 report. 



It was found that all the bindings examined showed 

 evidence of decay, but the books bound during the last 

 80 or 100 years were in a worse condition than many 

 of those of an earlier date; some recent binding had 

 deteriorated in as short a period as five years. The 

 deterioration became more general in books bound 

 after 1830 j some leather seemed to be good until i860, 

 after which date nearly all leather appeared to get 

 worse. 



Besides the quality of the leather, the conditions 

 under which book- are kept have a great influence on 

 the durability of the bindings. When ventilation is 

 good and artificial light is not used the books are in 

 a better condition. The products of the combustion 

 of gas do much mischief, especially on the upper 

 shelves of a library, where the temperature is often 

 ■considerably raised by the heat from the flames. Sad 

 to relate, tobacco smoke is said to be deleterious. 

 Daylight, and especially direct sunlight, has a bad 

 effect on spme leathers and also on the colours of the 

 dyes. 



The report discusses fully the durability of the dif- 

 ferent kinds of leathers which have been used for 

 bookbinding and also the construction of bindings ; a 

 specification for binding heavy or valuable books and 

 also one for ordinary library binding are given. 



The second subcommittee investigated the cause of 

 decay by many experiments. Three different kinds of 

 skins were tanned with eleven different agents, the 

 tanning process being modified in portions of the 

 specimens. Small strips of the leathers were fastened 

 on boards with one half of each strip exposed and then 

 submitted to various actions — direct sunlight, light 

 from a fish-tail gas-burner, light from an incandescent 

 gas-burner and from an incandescent electric lamp, the 

 fumes and heat of burning gas, currents of moist and 

 dry air alternately in a closed vessel kept at a tempera- 

 ture of 6o° to 70 F., carbonic acid gas, and sunlight, 

 but protected from air b\ glass; the results of many 

 "I these experiments are shown by excellent coloured 

 plates. 



Experiments wen mad" with purchased leathers, 

 11, est of which were found to contain free sulphuric 

 arid ; this acid has been used of recent years for 

 brightening the colour oi bark-tanned calf, from 

 which it removes the iron and tan stains, and much 

 improves the appearance of the material, It was 

 found that in every ease the presence of sulphuric arid 

 hastened the destruction of the leather by all the 

 agents tried. The sulphuric acid cannot be entirely 

 removed from the leather by washing with water; a 

 piece el leather containing 1 per cent, of sulphuric 

 ,n ill was washed for five days and nights in running 

 water, and was afterwards found to contain one-fifth 

 "I Mm original quanlin oi arid. It was found, how- 

 ever, that il leather containing sulphuric acid is 

 washed with potassium or sodium lactate or acetate 

 the effects ol the sulphuric acid are neutralised. 



Sulphuric arid is also introduced into leather by 

 the pickling which is used for preserving skins that 

 NO. l88S, VOL. 7$] 



are imported from New Zealand and Australia, the 

 process consisting of acting on the skins with a solu- 

 tion of salt and sulphuric arid. Mr. Seymour-Jones 

 has shown that formic acid may be used in the place 

 of sulphuric acid, and is quite as efficacious. Sul- 

 phuric acid is employed in the dye bath for the pur- 

 pose of liberating certain colours; it has been found 

 that in this case also formic acid may be substituted. 



Mr. Seymour-Jones has made a number of deter- 

 minations of the mechanical strength of skins in 

 their original condition, a.nd also after tanning and 

 other processes; it was found that the breaking stress 

 of the leather is always below that of the original 

 skin. 



Valuable sections on the preparation of leather suit- 

 able for bookbinding, on bookbinding, and on the pre- 

 servation ul books appear in the report. Appendix i. 

 consists of hints to owners and keepers of libraries by 

 the chairman, Lord Cobham. Appendix ii. is on the 

 fading of colour from sumach-tanned leather dyed 

 with coal-tar colours, by Mr. M. C. Lamb, and is 

 illustrated by coloured plates. 



The book is excellently printed and illustrated, and 

 inside the rover are specimens of six varieties 

 of leather in their undyed and dyed conditions. The 

 report should be read by all interested in books and 

 libraries. H. M. 



OUR BOOK SHELF. 



.1 Treatise on Ore and Stone Mining. By Sir C. 

 Le Neve Foster. Sixth edition, revised and enlarged 

 by Bennett H. Brough. Pp. xxx + 799. (London : 

 Charles Griffin and Co., Ltd., 1905.) Price 34s. 



Tins book, when it first appeared in 1894, was the 

 first systematic treatise on mining published in 

 England, and was quite up to date; but later editions 

 were not sufficiently revised, and the hand of death 

 put an end to the gifted author's intentions of re- 

 writing the work. The preparation of a new edition 

 could not have been entrusted to more competent 

 hands than those of his old colleague Mr. Bennett 

 H. Brough. The general arrangement of the book 

 is the same as in former editions, except that 

 chapter xiv., " Principles of Employment of Mining 

 Labour," has become chapter xvii. 



The revision of the whole work has been very 

 thorough ; recent discoveries of important occurrences 

 of minerals and new methods of mining and treating 

 ores have been brought up to date, while other 

 methods, machinery and appliances, which have been 

 superseded during the last few years, are omitted 

 from this edition. 



Additions to the work are interspersed throughout, 

 so that it is difficult to make selections. More 

 prominence is given to the important iron-ore deposits 

 "I Sweden and Norway, also to those of Spain. The 

 various kinds of steam turbines, which may, under 

 certain conditions, be used to advantage as motors 

 for pumps, are briefly described. A considerable 

 addition has been made to the list of important per- 

 cussive rock drills now on the market. The Water 

 Leyncr rock drill with its water-flushing apparatus, 

 which tends to prevent miners' phthisis, is introduced 

 to the reader, and the recent important investigations 

 of Dr. Haldane and Mr. Thomas into the mortality 

 of Cornish miners receive the attention they deserve. 



