Sciencemadness Discussion Board

The Joy's of Bench Chemistry - Humphrey Davy

The WiZard is In - 29-4-2010 at 16:45

It was my good fortune to be visiting my good friend Humphrey Davy and
his brother John during his "Capital experiment" on that 6th of October, 1808.

He that very day found although when perfectly dried by ignition, potash is a
non-conductor it could be rendered a conductor, by a very slight addition of
moisture, with out perceptibly destroy its aggregation; and in this state it readily
fused and could be decomposes by a strong electrical power. He then exposed a
piece of pure potash for a few seconds to the atmosphere, so as to give it
conducting power to the surface, and then placed it upon an insulated disc of
platina, connected with the negative side of a battery of 250 of the power of 6
and 4, in a state of intense activity ; then he connected a platina wire,
communicating with the positive side of the battery, and brought it into contact
with the upper surface of the alkali. The whole apparatus being in the open
atmosphere. A vivid action was soon observed to take place. The potash began
to fuse at both its points of electrization. There was a violent effervescence at the
upper surface; at the lower, or negative surface, with no liberation of elastic fluid,
however, small globules having a high metallic lustre, and being precisely
similar in visible characters to quicksilver, soon appeared, some of these burnt
with explosion and bright flame, as soon as they were formed, others remained,
and were merely tarnished, and finally covered with a white film which formed on
their surfaces. (When HD saw the minute globules of potassium burst through
the crust of potash, and take fire as they entered the atmosphere, he could not
contain his joy—he actually bounded about the room in ecstatic delight ; and some
little time was required for him to compose himself sufficiently to continue the
experiment.) These globules, numerous experiments soon showed to be the
substance was the peculiar inflammable principle the basis of potash.

pantone159 - 29-4-2010 at 17:57

That is one of my favorite element discovery stories. I'd like to hear some details of the discovery of neon, I figure the first thing they would try would be to put a spark across it and look at the spectrum, and that must have been a joy to discover!

The WiZard is In - 29-4-2010 at 18:36

Quote: Originally posted by pantone159  
That is one of my favorite element discovery stories. I'd like to hear some details of the discovery of neon, I figure the first thing they would try would be to put a spark across it and look at the spectrum, and that must have been a joy to discover!



I found the what to search for in Vol. VII or Mellor's 16 vol. opus.

About the time referred to, Dr. W. Hampson kindly offered to supply us with liquid air, and in February 1898 we commenced the preparation of a large quantity of argon (p. 105) for the purpose of the investigation. By the end of May,, about 15 litres of the gas had been obtained, and on fractional distillation it yielded a quantity of a gas of density intermediate between that of helium and argon. This gas, to which we gave the name neon, was afterwards shown to contain a small quantity of helium (p. 217).

The experimental study of gases: an account of the experimental methods ... 1901
By Morris William Travers [and Ramsay discovered neon.]

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