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558 BERGMAN landscapes with groups of figures and cattle, are careful in finish, effective in composition, and harmonious in coloring. The atmospheric effects are admirable. There are 11 of his pic- tures in the Louvre, 18 in the museum of the Hermitage at St. Petersburg, and others in England, at Amsterdam, Vienna, and else- where. He left a great number of pictures and a number of exquisite drawings and etchings. His works bring high prices. BERGMAN, Torbern Olof, a Swedish chemist and naturalist, born at Katarinaberg, in West Gothland, in March, 1735, died at Medevi, July 8, 1784. Intended by his father for the law or the church, he was sent to the university of Upsal, where he injured his health by exces- sive study, and applied himself by way of recreation to botany and entomology. He sent to Linnsus several insects previously unknown in Sweden, and devised a new method for their classification founded upon the characteristics of the larvfe. His first paper, published in the memoirs of the academy of Stockholm in 1756, narrated the discovery that leeches are oviparous, and that the substance called coccus aguaticin is the ovum of a species of leech containing several of the young animals. Lin- neeus wrote upon the memoir as he gave it his sanction, Vidi, et olstupui. Bergman devoted himself from this time to almost every branch of science. He presented memoirs to the academy upon attraction, electricity, twilight, the rainbow, and the aurora borealis ; became in 1761 adjunct professor of physics and math- ematics at Upsal, and was appointed in the same year one of the astronomers to observe the first transit of the planet Venus over the sun. In 1758 an association of savants was formed for the purpose of advancing knowl- edge of the earth ; to each of the members a particular portion of the subject was assigned, and Bergman received the department of phys- ics. The report which he made after eight years of study was rapidly sold and translated into foreign languages. In 1766 he was ap- pointed to the chemical chair of the university, and immediately silenced the murmurs of his opponents by publishing a curious and original memoir on the manufacture of alum. From this time he devoted himself wholly to the study of chemistry, and determined to banish from chemical science all preconceptions, and to proceed only by observation of facts. He published in 1774 a paper " On the Aerial Acid," subsequently called carbonic acid, and proved that it was a new and distinct acid. By boiling nitric acid with sugar, gum, and other vegetable substances, he produced oxalic acid. He succeeded in analyzing mineral wa- ters, and formed factitious mineral waters by combinations of their elements. In his re- searches on this topic he adopted the opinion that caloric is a fluid, and was the first discov- erer of sulphuretted hydrogen, which he, called the hepatic gas. He was the first to employ the humid method in the examination of min- BERGONZI erals, and by combining it with the dry method he obtained a knowledge of the principal ele- ments of the emerald, topaz, sapphire, and other precious stones. He was the first also to derive important results in chemistry from the use of the blowpipe. All of his labors led him to a chemical classification of the minerals, ac- cording to which the genera were determined by the principal integrant elements, the species by the different degrees in which they were combined, and the varieties by the external form. Applying geometry to the forms of crystals, he laid the foundation for the theory of cry stallization afterward developed by Hatiy. He demonstrated that the superiority of cer- tain kinds of steel was due to the presence of manganese, and that the brittleness of steel in extreme cold was caused by siderite, a sub- stance which he thought a new metal, al- though it has since been recognized as the phosphuret of iron. The theory of affinities, proposed by Geoffrpy in 1718, had been the first step toward giving a philosophical founda- tion to the science of chemistry. Bergman, seizing upon this idea, made it almost his own by an immense number of new experiments, and presented chemical phenomena as only modifications of the great law which rules the universe. To the curious operations of the ele- ments when placed in juxtaposition two united elements being separated by the approach of a third with which one of them combines, and two compounds as they meet each other inter- exchanging some of their elements and thus forming two new compounds to these ele- mentary movements he assigned the name elective, and introduced the term elective affinities. His mathematical training is seen in the simple formulas by which he described chemical operations. He adopted the errone- ous though ingenious ideas of Scheele concern- ing phlogiston, and in general his discoveries of facts were of much more value than his theoretical explanations. His labors distin- guished him throughout Europe; he cor- responded with the principal contemporary chemists and physical philosophers, was a member of numerous learned societies, and received from the king of Sweden the order of Vasa. He remained at Upsal, though invited to Berlin by Frederick the Great, till the state of his health, broken by his immense labors, obliged him to repair to the mineral springs where he died. His "Physical and Chemical Essays " were translated into English by Dr. Edmund Cullen (2 vols., 1788; 3d vol., 1791). BERGOXZI, the name of a family of Italian stringed instrument makers. I. Carlo, born and died at Cremona. He was a pupil of Stradi- varius, and was actively employed in the con- struction of violins, violas, and violoncellos from 1716 to 1755. He often imitated his master's style, especially in the purfling and the form of the sound hole. He had also the secret of the varnish which lent so much beauty to the vio- lins of that maker. He was chiefly renowned