To estimate safety of the book, it is necessary to analyse its smell. It is required to define level of concentration of flying organic substances (ЛОВ) which are allocated with a paper in the course of ageing.

The idea of creation of the test has come to researchers, during supervision over work of keepers of museums: they always sniff at books during an estimation of their condition.

The new test is based on a method of a gas chromatography-mass spectrometry: the special vacuum device (mass spectrometer) "sniffs" at the book, without damaging thus a paper, and allocates from a smell organic flying substances. The structure of mix ЛОВ depends on an initial chemical compound of the paper basis, the substances put on it and cover.

During test of a technique scientists have checked up 72 historical documents dated on the XIX-XX-th centuries; some of them have been got at on-line auction eBay. The analysis of their smells has allowed to identify fifteen connections which serve as reliable markers of ageing of a paper from hundreds mixes. Measurement of concentration of these substances allows to create unique "print" of a condition of each document.

Researchers say that their working out will help museums and libraries in time to find out books and documents which more than the other require immediate protection against ageing. Thus it will be possible to keep the archives which are of great value for descendants. By the way, as scientists mark, the technology can be applied at work not only with books, but also with other historical artefacts.