136 Answers to Queries. 
per cent. of Ammonia, so that if these figures be correct, that 
amount of 880 ammonia must be taken to contain 32°8 parts of 
ammonia, and this be diluted to 100 parts. To do this, take 845 
parts by measure of the strong solution, and dilute to 100 parts, 
or 845 parts, and dilute to rooo, jo Wee 
371.—Lithium.—Zinc and copper enter into the composition 
of plants growing near metallic mines, as in Zhalspi alpestre, var. 
calaminare ; Titaniums and bluminium are constituents of the ash 
of certain species of Lycopodium, cobalt nickel, strontium, and 
barium have also been met with in exceptional cases, and are the 
non-essential or accidental ingredients. V. Agee 
371—Plant Constituents——Lead, nickel, cobalt, tin, etc., are 
found in the ash of plants growing in soils containing these 
minerals. Lead and arsenic have been found in the ash of grasses 
grown in the neighbourhood of lead works, It is, however, pretty 
certain that the minerals thus obtained were not actual constituents 
of the plant, but merely attached to the surface in the form of 
minute dust. 
Some of the other minerals found occasionally in plants are 
probably present in the same form, as, for example, cobalt, nickel, 
tin, and zinc. Czsium was found by Sonstadt in seaweed, as 
well as Strontium, the latter in minute and doubtful traces. Copper 
is frequently found in wheat and other cereals, as well as in sea- 
weed and hay, indeed Odling and Dupré, (Guy’s Hospital reports, 
1858,) state that small quantities of copper are constantly found in 
‘flour, straw, hay, meat, eggs, and cheese,” Zinc is found in the 
ash of a species of violet, Vzola calamtnaria, which grows on the 
rubbish heaps at calamine mines in Rhenish Prussia. Barium has 
been found in the ash of wheat grown in Nile mud, which contains 
a distinct per centage of barium carbonate. J: Wea 
372.—Microscopes.—R. C. should if possible get a friend to 
choose an instrument for him if he can. To work with a dissecting 
microscope would be most injurious to his eyesight, except for 
what its name applies. A microscope by Leitz and Co, 43 3s. 
(upright stand and immovable is its objection), is a very good and 
cheap instrument. Beck’s Star, Aylward’s Small College, and 
Swift’s Students, are all good, and to these, at any time, may be 
added objectives and other apparatus, which is much the best way, 
and saves expense and getting a number of useless articles which 
may never be used. Smith “ How to Use a Microscope,” 1s. 
Pamphlet by Crouch, Journal of Postal Society, Vol. iv., 1885, p. 22. 
* Howto Use the Micros,” Gage on ** Microscopical Technology,” 
(U.S) Frank L. James, Elementary Micros. Technology. 
- V. A. LATHAM. 
