From Oracle Bone Inscriptions to microfilm.
Formal books appeared in the Spring and Autumn Period and the Warring States Period more than two thousand years ago. At first, people wrote on bamboo chips or wood chips, which were called bamboo slips or bamboo slips. The bamboo board is split into strips of equal length and width (usually 5 inches to 2 feet long) and the surface is flattened. On them, write with a knife or a brush, and each piece can write 8 to 14 words. Some of them are simplified.
Of course, this heavy book is extremely inconvenient to use. It is said that the bamboo slips and slips examined by Qin Shihuang every day weigh 120 Jin. In the Western Han Dynasty, Dong Fangshuo wrote an article to Emperor Wu of the Han Dynasty, using 3,000 pieces of bamboo slips.
Nowadays, there are not only many kinds of books, but also some kinds are getting smaller and smaller. "Microfilm" is one of them. It uses a camera to reduce books or materials to film, generally to 1/48 the size of the original book. When in use, it can be enlarged to the original size by a reader. In fact, this microfilm technology was used as early as the Franco-Prussian War in the19th century, when it was a French spy.
Microform books are very convenient to store and use. If you put 10000 kinds of books 15000 words together, the total weight is about 5 tons, while microfilm is only 15 kg.
With the development of science, books are constantly evolving, feeding people who study hard with more and more nutrients.