78 Tue Microscope. 
exists. What ideas our lexicographer had when framing them © 
is even beyond the imagination. 
‘“‘ Mountain soap, in mineralogy, a variety of green earth of 
a brownish or blackish color.” 
‘“ Thallite, in mineralogy, a substance variously denominated 
by different authors.” 
‘““ Plumbane, achlorideof lead. It is the substance of which 
writing and other pencils are made. The finest kinds of it are 
found at Borrowdale, in Cumberland, from which a specimen 
was found to contain carbon, silica, alumina, oxide of iron and 
manganese, and water.” 
‘Piano monitor is a bar of metal placed above and a little 
before the keys of a pianoforte, for enabling the young prac- 
titioner to rest on.” N. 
REPLY TO PROF. WEBER. 
BY DR. THOS. TAYLOR, WASHINGTON, D. C. 
N answer to yours of the 6th inst., in reply to Prof. Weber’s 
discovery of a cross on globules of fat, produced by tritur- 
ating lard and beef oil, with salt and water; I have to say, that 
his process breaks up the fatty liquids into microscopic globules 
each one having a film of water. This agrees with a statement 
made by me which appears in my paper on “Butter and Fats,” 
in the published proceedings of the American Microscopical So- 
ciety of last year, which you have, see page 152, viz: Thata 
body which is globose, translucent, smooth, and polarizing, will 
exhibit the St. Andrew’s cross under polarized light. Starch, 
when moist and translucent shows the cross. 
When the fatty solution, as prepared by Prof. Weber, is 
deprived of its moisture, the cross is no longer seen, the glo- 
bules having become again a homogeneous mass. 
The crystal of butter differs in this that when viewed by 
transmitted light it is seen to be a crystallized fat. 
Prof. Weber’s globules have no crystallization. The pro- 
cess the fats undergo by his method, does not destroy the stel- 
lated crystal of lard, and therefore the microscope will always 
demonstrate their true origin. 
When I examine oleomargarine for the purpose of assist- 
=< = 
