358 Dr. A. Wilmore—Uratite and other Amphiboles. 
In giving reasons for the grouping of hornblendes and augites into 
one family, he called attention to the fact that when hornblende is 
fused in a platinum or graphite crucible, crystals result which have 
the form of augite. Augite crystals are found in slags, but never 
hornblende crystals. The melting-point of hornblende is lower than 
that of augite. In 1833 Rose gave further localities for uralite.1 
Meanwhile Professor Glocker had cast doubts on the secondary 
origin of this uralite; he had suggested that it might be due to 
hornblende enclosing, in crystallizing, a core of augite, or that an 
original crystal of augite had had a zonary growth of hornblende 
formed round it (Schwegger’s Jahrbuch, Bd. v, p. 873). Rose 
replied to these suggestions, and insisted on the unity of the augite 
- and hornblende families. He also gaye further localities for secondary 
hornblende.* Rose then discussed the question whether hornblende 
and augite should be considered as two dimorphous substances, and he 
showed that though their chemical composition is very similar it is 
not identical. Later on he suggested the possibility of the change 
from augite to hornblende being due to the higher oxidation of the 
ferrous oxide of the augite. 
These observations of G. Rose are the first systematic descriptions 
of a secondary mineral, and are the precursors of much important 
work in connexion with changes in the minerals of rocks which could 
only be carried out after the application of the microscope to petro- 
logical study. 
The subject does not seem to have attracted much attention until 
the era of microscopic petrology had dawned, but from 1876 onwards 
one finds a continuous series of important papers dealing more or less 
directly with uralite. 
In 1876 J. A. Phillips called attention to the ‘‘ pseudomorphic 
origin’? of many of the minerals of the greenstones of Western 
Cornwall.? Some of the rocks are gabbros or dolerites, in which the 
original constituent minerals are occasionally, to a great extent, 
unchanged, but are sometimes almost entirely represented by 
‘* pseudomorphic forms ’’. 
In the same year 8. Allport described the rocks surrounding the 
Lands End mass of granite. Allport made an interesting observation 
which shows that he regarded the process as almost entirely one of 
paramorphism. ‘‘ The alteration that has taken place appears to be 
the result of internal rather than of external action; in other words, 
it must have been caused by a more or less complete decomposition 
and re-arrangement of mineral substances in situ, and not to any 
great extent by the introduction of new material from without.” . 
This seems to have been one of the first suggestions, that the 
production of hornblende by change from augite is one of simple 
paramorphism, an idea which was afterwards developed more fully, 
especially by G. H. Williams. As will be seen later, it does not now 
seem feasible to regard the change as of so simple a nature, at any 
Pogg. Ann., Bd. xxvii, pp. 97-106. 
Tbid., 1834, Bd. xxxi, pp. 609-22. Dana gives the date as 1831. 
Quart. Journ. Geol. Soc., 1876, vol. xxxii, pp. 155-78. 
4 Ibid., pp. 407-27. 
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