POTA3ICJM. 



cued turmeric paper, it immediately 

 burns, and moves rapidly upon the pa- 

 per, as if in search of moisture, leaving 

 behind it a deep reddish brown trace. 

 So strong 1 is the attraction of the basis 

 of potash for oxygen, that it discovers 

 and decomposes the small quantities of 

 water contained in alcohol and ether, 

 even when they are carefully purified. 

 When thrown into the mineral acids, it 

 inflames and burns on the surface. In 

 sulphuric acid, sulphate of potash is 

 formed ; in nitrous acid, nitrous gas is 

 disengaged, and nitrate of potash form- 

 ed. When brought in contact with a 

 piece of phosphorus, and pressed up- 

 on, there is a considerable action : they 

 become fluid together, burn, and pro- 

 duce phosphate of potash. When a glo- 

 g-ule is made to touch a globule of 

 mercury about twice as large, they com- 

 bine with a considerable heat ; the com- 

 pound is fluid at the temperature of its 

 formation : but when cool it appears as 

 a solid metal, similar in colour to sil- 

 ver. If this compound be exposed to 

 air, it rapidly absorbs oxygen ; potash 

 which deliquesces is formed ; and in a 

 few minutes the mercury is found pure 

 and unaltered. 



When a globule of the amalgam is 

 thrown into water, it rapidly decompo- 

 ses it with a hissing noise, potash is 

 formed, hydrogen disengaged, and the 

 mercury remains free. The basis of pot- 

 ash readily reduces metallic oxides when 

 heated in contact with them. It de- 

 composes common glass by a gentle 

 heat, and at a red heat effects a change 

 even in the purest glass. Mr. Davy 

 'has discovered that its base, like that 

 of potash, is white, opaque, and has 

 the lustre of silver. The property of 

 welding, which belongs to iron and 

 platina) at a white heat only, is possess- 

 ed by this substance at common tem- 

 peratures. It is very similar, in its 

 more obvious properties, to the base of 

 potash ; but it has greater specific gra- 

 vity, being to that of water nearly as 

 nine to ten, or as 9348 to 1.0000. In 

 oxygen gas it produces a white flame, 

 and sends forth bright sparks, occasion- 

 ing a very beautiful effect. In oxy-mu- 

 yiatic acid gas it burns vividly, with 

 numerous scintillations of a bright red 

 colour. In the quantity of -JL, it ren- 

 ders mercury a fixed solid, of the co- 

 lour of silver, and forms an alloy with 

 tin. When amalgamated with mercury, 

 the amalgam will combine with other 

 metals. 



Mr. Davy tried this with iron and pla- 

 tina, and had reason to believe that these 

 latter metals remain in combination with 

 the mercury, even when deprived of the 

 new substance by exposure to the air. 

 From several curious and ingenious ex- 

 periments to ascertain the proportions of 

 the bases and oxygen in the two fixed al- 

 kalies, he concludes that 100 parts of 

 potash consist of about 84 basis, and 16 

 oxygen ; and 100 parts of soda consist 

 of about 76 or 77 basis, and 24 or 23 

 oxygen ; or that potash may be consi- 

 dered as consisting of about 6 parts 

 basis, and 1 of oxygen ; and soda of 7 

 basis, and 2 oxygen. In reply to the ques- 

 tion, whether the bases of potash and soda 

 should be called metals, it may be said 

 that they agree with metals in opacity, 

 lustre, malleability, conducting powers 

 as to heat and electricity, and in their 

 qualities of chemical combination. Even 

 their low specific gravity does not ap- 

 pear a sufficient reason for making them 

 a new class; for amongst the metals 

 themselves there are remarkable diffe- 

 rences in this respect, platina being near- 

 ly four times as heavy as tellurium ; and 

 tellurium is not much more than six times 

 as heavy as the basis of soda. Conceiving 

 the basis of the two fixed alkalies to be 

 metals, Mr. Davy has named one Potasi- 

 um, and the other Sodium ; adopting that 

 termination which, by common consent, 

 has been applied to other newly discover- 

 ed metals. 



On an examination of the volatile alka- 

 li, and after a great number of complex 

 and tedious experiments, Mr. Davy saw 

 reason to conclude that ammonia contains 

 oxygen as an essential ingredient, and 

 that this cannot well be estimated at less 

 than 7 or 8 parts in the hundred : this 

 body may therefore, as he says, be con- 

 sidered as the principle of alkalescence, 

 with as much reason as the French have 

 made it the principle of acidity. After 

 making some general remarks on the 

 preceding facts, he suggests the proba- 

 bility, that the muriatic, fluoric, and bo- 

 racic acid all contain oxygen as one of their 

 constituent principles. The earths of 

 barytes and strontian, as being most ana- 

 logous to the alkalies, were likewise ex- 

 amined, and both yielded oxygen. In con- 

 cluding this very important communica- 

 tion, Mr. Davy remarks, that an immense 

 variety of objects of research is present- 

 ed in the powers and affinities of the 

 new metals produced from the alkalies. 

 In themselves they will undoubtedly 

 prove powerful agents for analysis ; and 



