280 



every fluid in which they are attempted to be kept, and more or less 

 on the solid ingredients of the vessels in which they are examined. 



The fluid substance containing the least oxygen, and consequently 

 best adapted for preserving them, is naphtha recently distilled. In this 

 they may be kept many days without any considerable change ; and 

 when taken out of it, their physical properties may be conveniently 

 examined in the atmosphere while their surface is yet moist, and pro- 

 tected by a thin film of naphtha. 



The base of potash, at the temperature of 60, appears as a fluid 

 globule, having the full metallic lustre, opacity, and so much the ge- 

 neral appearance of a globule of mercury, that a difference cannot be 

 detected by the eye. Its fluidity, however, even at this temperature, 

 is not perfect, and at 50 it becomes a soft solid ; at 40 it is mal- 

 leable, and has the lustre of polished silver : at about the freezing 

 point of water it is brittle, and when broken, its fragments exhibit a 

 crystalline texture. 



When its temperature is, on the contrary, raised to 100, its fluidity 

 is perfect ; and when it is heated to a degree approaching to redness, 

 it boils, and after distillation is found in its condensed form unaltered. 

 Like metals, it is a perfect conductor of electricity ; but when the 

 globule exposed is too small for the quantity of electricity to be 

 transmitted, it is completely dissipated with explosion, accompanied 

 with a vivid white light. 



It is also, like most known metals, an excellent conductor of heat, 

 when brought into contact with mercury, &c. When the base of 

 potash is brought into contact with mercury, it instantly amalga- 

 mates. If the globule of mercury be much the larger, the compound 

 appears to be more fluid than mercury ; but when the mercury ex- 

 ceeds in size only in the proportion of 2 to 1, the compound, though 

 fluid at first from the heat of union, consolidates as it cools, and ap- 

 pears as a soft metal, similar to silver. 



The fluid compound unites with all metals that have been exposed 

 to it, acting readily even upon iron and platina. 



The base of potash will also combine with other metals without 

 the assistance of mercury, if applied to them in its fluid state ; and 

 it is remarkable, that in most instances the point of fusion of the 

 compound is much higher than could be expected from that of the 

 ingredients. 



With sulphur and with phosphorus it also combines, and the com- 

 pounds agree in appearance with the metallic sulphurets and phos- 

 phorets. 



But though it resembles the metals in all these properties, it dif- 

 fers from all most remarkably in specific gravity, since it rises to the 

 surface even in doubly-distilled naphtha, of which the specific gravity 

 is only -rVoth of water. 



As the quantity which can be obtained is necessarily small, it is 

 difficult to determine any points in which quantities are concerned, 

 with minute precision ; and accordingly the average obtained from 

 several experiments, conducted with great care, and with a very 



