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THK PUOGKESS OF 



in 1752 Baron showed that borax is a compound 

 ofboracic acid and soda. In 1808, Gay-Lussar 

 and Thenard, by heating boracic acid and potas- 

 sium, decomposed it, and obtained its basis, to 

 which the name of boron has been given. It is 

 a black powder like charcoal, possessing peculiar 

 properties; burning when healed in contact \\ith 

 air or oxygen gas, and being converted into 

 boracic acid. 



Silica is one of the most abundant substances 

 in nature, and under the name of rock crystal 

 was known to the Greeks. But iU chemical pro- 

 perties were first accurately investigated by 

 Bergniann and Scheele. Berzelius, in 1824, 

 succeeded in showing it to be a compound of 

 oxygen, and a black substance called silicon, 

 very similar in many of its properties to char- 

 coal, though quite different in others. For 

 rvtiiiple, it does not burn when heated in air or 

 oxygen gas ; but it burns when heated with car- 

 bonate of potash. 



Phosphorus was accidentally discovered by 

 Brandt in 1669 ; selenium by Berzelius in 1818; 

 tellurium was pointed out, with some hesitation, 

 by 31 11 Her of Reichenstein in 1782; and its 

 characters finally determined by Klaproth in 

 1798. 



The white oxide of arsenic was known to the 

 Arabians ; but we do not know who first attend- 

 ed to its metallic basis,. though as this basis is 

 found in the earth in the metallic state, it could 

 not have escaped altogether the attention of 

 miners and metallurgists. Paracelsus seems to 

 allude to it ; and Schroeder, in his Pharmacopoeia, 

 published in 1649, gives us a process for obtain- 

 ing it. Its characters were first determined by 

 Brandt in the year 1733. 



The ancients were acquainted with the oxide 

 and sulphurct of antimony, but not with the 

 metal. When the metal became known, we do 

 not know, but Basil Valentine was acquainted 

 with it in the 15th century. 



Chromium was discovered by Vauquelin in 

 1797 ; uranium by Klaproth in 1789 ; vanadium 

 by Sefstrom in 1830; molybdenum by Scheele 

 and Hjelra in 1778 and 1782; tungsten by 

 Scheele and D'Elhuyarts in 1781; columbium 

 by Hatchett in 1801 ; and titanium by Gregor in 

 1791. 



The alkalifiable bases are thirty-one in num- 

 ber. We have already given the history of the 

 discovery of the first thirteen of these, constitut- 

 ing the bases of the fixed alkalies, alkaline 

 earths, and earths proper. The ancients were 

 acquainted with iron, lead, tin, copper, mercury, 

 silver, and gold. Manganese was discovered by 

 Scheele in 1774, and reduced to the metallic 

 state by Gahn soon after ; nickel was examined 

 by Cronstedt in 1751 ; cobalt by Brandt HI 1733. 



Zinc appears to have been known in China and 

 the East for many ages ; but it was never smelt- 

 ed in Europe till Henkel pointed out a process 

 in 1721. Cadmium was discovered by Stromeyer 

 in 1817. Bismuth occurs native in some of the 

 'uTiuan mines; and was, of consequence, known 

 as soon as these mines were worked. Agricola 

 mentions it in his Hermannus, published in 

 1529; but Beccher, Pott, and Geoffroy Jiiniiu 

 were the first chemists who investigated its 

 properties. 



Platinum was known to the Spaniards soon 

 after the colonization of South America; but its 

 chemical properties were first investigated by 

 Scheffer in 1752, and still more completely by 

 Lewis in 175k Palladium and rhodium were 

 discovered by Dr Wollaston in 1803 and 1804 ; 

 and iridium and osmium by Mr Smithson Ten- 

 nant about the same time. 



The acids at present known to chemists amount 

 to 126. It would be too tedious a task to enu- 

 merate them all, and to point out the persons by 

 whom they were discovered. We may, however, 

 state that Scheele did more to improve this im- 

 portant branch of chemistry than any other in- 

 dividual He made known, and described no 

 fewer than eleven new acids; namely, fluoric, 

 molybdic, tungstic, arsenic, lactic, gallic, tartaric, 

 oxalic, citric, malic, and saclactic. It was he 

 also that first isolated the prussic acid, and com- 

 menced that interesting branch of chemistry 

 which was brought to perfection by Gay-Lussac, 

 when he discovered and determined the nature 

 of cyanogen, and the compounds which it forms. 



To Mr Dalton we are indebted for a branch ot 

 chemistry which promises fair to reduce the 

 science to the same accurate state which dis- 

 tinguishes astronomy, by the application of rigid 

 calculation. It had been observed before, that 

 bodies unite in definite proportions. He showed 

 that these proportions might be stated in num- 

 bers; and concluded that bodies unite atom to 

 atom, and that these numbers denote the relative 

 proportions of the weights of these atoms. Ber- 

 zelius first endeavoured to obtain accurate atomic 

 numbers by means of analysis. The result has 

 been a great improvement in the accuracy of 

 analysis, and much more correct notions respect- 

 ing the nature and properties of chemical sub- 

 stances than were formerly entertained. This 

 branch of the science is advancing apace. The 

 number of salts which have been formed, and 

 examined with more or less accuracy, amount to 

 about 2200, and their number is increasing daily. 



The application of chemistry to the vegetable 

 and animal kingdoms, the interesting facts laid 

 open respecting vegetable substances and vegeta- 

 tion, and the light thrown upon some of the 

 most important functions of living animals, con- 



