As he grew older it also became apparent that personal appearance became less and less significant to him. Many stories abound relating to the idea that in his later years, Dmetri would only cut his hair and beard once a year. He would not even cut it by request of the tsar. One observer stated, "Every hair acted separate from the others." It becomes apparent that, in most respects, work came first for Dmetri Mendeleev.
From his first publication in 1854 entitled "Chemical Analysis of a Sample from Finland" to his final works in 1906 such as "A Project for a School for Teachers" and "Toward Knowledge of Russia", Mendeleev's transcripts revealing his research findings and beliefs number well over 250. His most famous publications include Organic Chemistry, which was published in 1861 when he was 27 years old. This book won the Domidov Prize and put Mendeleev on the forefront of Russian chemical education. The first edition of Principles of Chemistry was printed in 1868. Both of these books are classroom texts. Again, Mendeleev never lost sight of the importance of education.
Besides his work on general chemical concepts as discussed earlier, Mendeleev spent much of his time working to improve technological advances of Russia. Many of his research findings dealt with agricultural chemistry, oil refining, and mineral recovery. Dmetri was also one of the founding members of the Russian Chemical Society in 1868, and helped open the lines of communication between scientists in Europe and the United States.
Mendeleev also pursued studies on the properties and behavior of gases at high and low pressures, which led to his development of a very accurate differential barometer and further studies in meteorology. He also became interested in balloons, which led to a rather perilous adventure in 1887. In order to observe the solar eclipse above Klin, he made a solo ascent, without any prior experience; while his family was rather concerned, he paid no attention to controlling the balloon until after he had completed his observations, at which time he figured out how to land his conveyance. (4,9)
His greatest accomplishment, however, was the stating of the Periodic Law and the development of the Periodic Table. From early in his career, he felt that there was some type of order to the elements, and he spent more than thirteen years of his life collecting data and assembling the concept, initially with the idea of resolving some of the chaos in the field for his students. Mendeleev was one of the first modern-day scientists in that he did not rely solely on his own work but rather was in correspondence with scientists around the world in order to receive data that they had collected. He then used their data along with his own data to arrange the elements according to their properties.
No law of nature, however general , has been established all at once; its recognition has always been preceded by many presentiments. The establishment of a law, moreover, does not take place when the first thought of it takes form, or even when its significance is recognized, but only when it has been confirmed by the results of the experiment. The man of science must consider these results as the only proof of the correctness of his conjectures and opinions. (9)
In 1866, Newlands published a relationship of the elements entitled the "Law of Octaves". Mendeleev's ideas were similar to those of Newlands but Dmetri had more data and felt that Newlands had not gone far enough in his research. By 1869, the Russian chemist had assembled detailed descriptions of more than 60 elements and, on March 6, 1869 a formal presentation was made to the Russian Chemical Society entitled "The Dependence Between the Properties of the Atomic Weights of the Elements." Unfortunately, Mendeleev was ill and the presentation was given by his colleague Professor Menshutken. There were eight points to his presentation:
1. The elements, if arranged according to their atomic weights, exhibit an apparent periodicity of properties.
2. Elements, which are similar as regards their chemical properties, have atomic weights, which are either of nearly the same value (eg. Pt, Ir, Os) or which increase regularly (eg. K, Ru, Cs).
3. The arrangement of the elements, or of groups of elements in the order of their atomic weights, corresponds to their so-called valences, as well as, to some extent, to their distinctive chemical properties; as is apparent among other series in that of Li, Be, Ba, C, N, O, and Sn.
4. The elements that are the most widely diffused have small atomic weights.
5. The magnitude of the atomic weight determines the character of the element, just as the magnitude of the molecule determines the character of a compound body.
6. We must expect the discovery of many as yet unknown elements-for example, elements analogous to aluminum and silicon- whose atomic weight would be between 65 and 75.
7. The atomic weight of an element may sometimes be amended by knowledge of those of its contiguous elements. Thus the atomic weight of tellurium must lie between 123 and 126, and cannot be 128.
8. Certain characteristic properties of elements can be foretold from their atomic weights. (18)