32 SCIENCE PROGRESS 
Wwe may note that M. de Lapparent! is content to attribute 
early observations on this matter to Kreil (1849), who also 
worked among the Alps, and to Locke (1846), who made 
investigations in North America. 
Korda? states that as early as 1778 Brugman, of Leyden, 
had described many minerals as being magnetic, including 
those which contained iron and cobalt. The same author 
states that in 1792 Fullerton obtained in England a patent 
for separating magnetic from non-magnetic materials by means 
of permanent magnets. 
The Pen ees of this period were familiar with the wide 
distribution of magnetite in eruptive rocks; they were in the 
habit of extracting it from crushed rocks by means of a magnet, 
and of noticing that the rocks which contained it affected the 
magnetic needle. In 1794 Dolomieu® characterised his group 
of compact basic volcanic rocks as having, among other things, 
a marked effect on the magnetic needle. He observed that 
specimens of certain lavas exhibited a well-marked polarity, 
which was retained by the fragments when the specimen was 
broken. 
In 1800 Bellevue * recommended the partial crushing (demi- 
trituration) of rocks, and mechanical analysis (analyse mécan- 
ique) of the fragments, including elutriation and treatment with 
a bar magnet. In this way he made a thorough examination 
of the leucite-nepheline-melilite-basalt of Capo-di-Bove, making 
a fairly full record of its mineral composition. He concluded 
his interesting memoir by stating his belief, that the adoption of 
the methods he describes would be a potent means of discovering 
new minerals, and of elucidating the nature of rocks. It is 
instructive to note the acute observations made by these early 
workers, and not a little surprising to find that they achieved 
so much with the limited means at their disposal. Bellevue 
especially emphasised the importance of examining the sands 
which had resulted from the disintegration of rock masses. 
As if to show that he had appreciated the importance of 
1 Traité de géologie, 1906, tome i. p. 106. 
? La séparation électromagnétique et électrostatique des minerals, Paris, 1905. 
3 “Suite de mémoire pour servir d’explication a la distribution méthodique de 
tous les produits volcaniques,” Journal de Physique, etc., 1794. 
* “Mémoire sur les cristaux microscopiques,” Journal de Physigue, tome li. 
1800, 
