228. Scientific Intelligence. ([Marcn, 
formed with a round grained sand, such as glass grinders use. 
This mass of sand vitrifies, and becomes extremely hard, but 
porous ; so that in the melting of copper, grains of the metal 
will insert themselves. The great proportion, however, in the 
mass, exists in a state of oxide ; and by the continued use of the 
furnace, the greater proportion of the sand will be regularly 
converted into a red coloured copper ore. In the instance in 
question, the mass of sand converted into this red coloured ore 
exceeded six inches. 
VI. Fall of Stones from the Atmosphere. 
Among the very minute historical details of the falls of stony 
bodies from the atmosphere, from the earliest ages down to our 
own time, which have been successively published by Dr. Chlad- 
ni, I do not find the followmg. The attention of meteorolo- 
gists has been drawn to it by Sig. Domenico Paoli, in a letter 
published in Brugnatelli’s Journal for July and August, 1818. 
The passage quoted is taken from the fifth chapter of the first 
book of a work published by Camillo Leonardi, in the year 1502. 
The title of the’ book is Speculum Lapidum. ’ Leonardi was an 
inhabitant of Pesaro, in Italy, where his book was published. 
The passage is as follows : 
“Et non solum in locis his dictis lapides generantur, verum 
etiam et in aere, sicut habetur a philosophis, et maxime ab 
illo summo philosopho, ac nostris temporibus monarea, pre- 
ceptore meo Domino Gaetano de Fienis, in ¢omento metau- 
rorum, in fine secundi tractatus libri tertii, qui dicit: Lapides 
generarl possunt in aere, cum exhalatio habet partes grossas 
terreas admixtas cum humiditate grossa viscosa. Et resolutis 
partibus magis subtilibus, et terrestribus condensatis a calido, fit 
lapis, qui ratione sue gravitatis ad terram descendit. Nostns 
temporibus, in partibus Lombardie lapis magne quantitatis ex 
nubibus cecidit.” 
VII. Blue Glass from Iron. 
It is pretty well known that the ancients were acquainted with 
a method of giving a fine blue colour to glass by means of iron. 
This method has been lost, probably because cobalt, the tinging 
substance used by the moderns, is much easier and much more 
certain of answering the object intended. Iron, however, if we 
are to judge from ultramarine, which owes its blue colour to iron, 
is capable of communicating a more beautiful colour to glass 
than cobalt ; besides, cobalt is a very scarce metal, and sells at 
a high price; while iron is the most abundant and the cheapest 
of all known metals. On these accounts, it would be.an object 
of considerable interest to painters, glass makers, and potters, if 
the ancient art could be again recovered. M.Pagot Descharmes 
has made a number of trials, and has made known the results 
which he obtained in a paper published in the Journal de Physique, 
for July, 1818. From the imperfect experiments which he. 
