466 
Facts and Observations. 
The Alkaline Metals. — Recent discoveries have 
doubled the number of these bodies. Originally they were 
potassium, sodium, lithium. To these must now be added, 
it appears, rubidium, caesium, and thallium. Not long 
since, an idea was entertained by some persons that chemists 
were about to return to the alchemical theory of transmuta¬ 
tion of bodies. This arose from an opinion broached by 
Dumas, that substances having the requisite similar relation¬ 
ship to each other might render this change possible. In 
the triad groups, so designated, this philosopher observed 
that the intermediate body has most of its properties inter¬ 
mediate with the properties of the two extremes. Take, for in¬ 
stance, sulphur, l6, silenium, 40, and tellurium, 64 : half of 
the extremes will give the intermediate number, 40. So 
chlorine, 35, bromine, 80, iodine, 125; here, again, the mean 
of the extremes of the group is 80. It is in such bodies or 
groups as these that transmutable changes may be hoped for; 
not in the conversion of lead into silver, or mercury into 
gold, the object for which alchemists untiringly worked. 
The commission appointed by the French Academy remark 
that the equivalent of sodium, 23, is exactly the mean be¬ 
tween that of potassium, 39, and lithium, 7. Further, that 
if double the weight of sodium be added to that of potassium, 
the equivalent of rubidium, 85, is obtained ; and by adding 
double the weight of sodium to double that of potassium, we 
obtain very nearly that of caesium, 120; while double the 
weight of sodium and four times the weight of potassium 
gives nearly that of thallium, 204, which stands in this list, 
as it regards the weight of its equivalent, in the opposite 
extremity of the scale to lithium. 
Obtainment of Iodine. —According to the statements 
made by Mr. E. C. C. Stanford, F.C.S., in the ordinary 
mode of obtaining kelp by the burning of sea-weeds a large 
portion of the salts of iodine, amounting to nearly one half, 
is driven off and lost. lie therefore proposes to distil the 
weed in closed vessels. By this mode of treatment, he says, 
all the iodine can be retained, the carbon wiW not be allowed 
to act upon the sulphates of potash and soda, all waste of 
weed will be obviated, and the charcoal left after the distilla¬ 
tion may be used, with other matters, for heating the retorts. 
