216 
THE CENTIGRADE THERMOMETER RECOMMENDED. 
methylic acid) and base, and considering the 
loss to be methylene. The compound with 
lime, consisted of i atom lime 2 atoms 
sulphuric acid l methylene. 
Some discussion took place in reference to 
the double atoms, of which the organic bases 
are stated to consist, according to the views 
of Continental chemists. Considerable 
misunderstanding was exhibited in many of 
the observations oliered upon this point. 
But it is unnecessary to repeat the statement 
of the various theories, as this has been 
already done in the previous number of this 
journal. 
4. Mr. fox described AN EXPERI- 
MENT WHICH HE HAD MADE, 
WITH REGARD TO THE EFFECT OF 
MELTED IRON UPON THE MAG- 
NET. 
He found that no action was exerted upon 
it. Hence, this is an argument’ against the 
idea of a central fire. 
5. A LETTER WAS READ FROM Dr. 
TURNER, REPORTING THE OPINI- 
ON OF THE COMMITTEE APPOINT- 
ED AT LAST MEETING, TO TAKE 
INTO CONSIDERATION THE ADOP- 
TION OF A UNIFORM SET OF CHE- 
MICAL SYMBOLS FOR THIS COUN- 
TRY. 
The opinion of the majority was, that those 
used on the continent should be had recourse 
to. It was strongly recommended that the 
abbreviations should not be carried further 
than the dots for oxygen ; indeed, it was 
suggested by some, that these should be 
rejected, as they merely express theory, and 
consequently vary, according to the view that 
is taken of the composition in this country 
and on the continent ; but it is obvious, that if 
brevity is not carried any further than this, 
no bad consequences can follow from a sys - 
tern of notation. 
Dr. Thomas Thomson strongly recom- 
mended that the centigrade thermometer 
should be adopted in this country for scien- 
tific purposes, as being infinitely better 
adapted for such purposes than that of Fah-, 
renheit. His suggestion appeared to coin- 
cide exactly with the opinion of the committee. 
Tuesday, l\th August. 
6. Mr. DAVY DETAILED SOME EX- 
PERIMENTS WHICH HE HAD MADE 
UPON THE PRESERVATION OF TIN 
PLATE BY THE AGENCY OF ZINC. 
When exposed for some days to the action 
of water, the plate by itself soon becomes 
slightly corroded, but is completely preserved 
by the zinc, the latter, at the same time, 
oxidizing. Hence, the plate might be em- 
ployed in place of copper for many purposes, 
where salt water comes in contact with 
vessels. • Several metals he had ascertained 
are not protected. 
7. MR. GRAHAM DESCRIBED THE CON- 
STITUTION OF CER'FAIN SALTS 
IN CONTINUATION OF THE PAPERS 
WHICH HE HAS PUBLISHED UPON 
THIS SUBJECT. 
He views sulphuric acid as a sulphate of 
water, and as represented by H S. Sulphu- 
ric acid of spec. grav. 1*78 is hydrous sul- 
phate of water, or a hydrate expressed by H 
S H, 1 atom being basic and essential to the 
composition of the acid, the other being 
driven off by heat. Hydrated oxalic acid is 
an oxalate of water H *(C C) H2. 
Nitric acid = H N H3 of spec. grav. 1’42. 
Oxalate of magnesia = Mg (C C) H2. 
Nitrate of copper = Cu N. H3 
There are three oxalates of potash, 
1. K (C -1- C) H. 
2. K (C + C) H (C’4* C)H2, orbinoxalate ; 
decomposes at 300® and loses 2 atoms. 
3. K (C + C) H C H (C + C) H3 
J H (C -k C) H2 or quad- 
roxatate, the 2 atoms of water in the binox- 
alate being replaced by hydrated oxalic acid. 
There are two remarkable salts, which 
correspond with each other in composition, 
viz., oxalate of potash and iron which is green, 
although the iron is in the state of peroxide, 
being precipitated i-ed by potash, and the 
oxalate of potash and chromium which is 
dark coloured. The first is represented by 
Fe (C -f- C)3 3 K (C -f C)+H6. 
If we substitute chromium for iron, we 
have the composition of the chromium salt. 
The same law in reference to water, it is 
probable, is generally applicable to the com- 
position of the carbonates. Carbonate of 
magnesia is i-epresented by Mg. CH2. At 
212’ the water is expelled. 
Bicarbonate of potash = K C H Cis a car- 
bonate of potash and a carbonate of water, 
because the latter can be readily driven off. 
Two additional atoms of water may exist in 
it. The bicarbonate of potash and magnesia 
of Berzelius, has the same composition as 
quadroxalate of potash, the symbol being K 
^ ^ ^ ^ Mg! C H 2 ( + making 9 atoms 
of water in the salt, and the magnesia occupy- 
ing the place of the water in the quadroxalate 
of potash. 
Rose described a class of salts formed by 
the absorption of dry ammonia. He consi- 
dered the ammonia not to act as a base, but to 
take the place of water. 
Mr. Graham coincides with him in opini- 
on. The composition of ammonia may be re- 
represented by N H 3 N H 3 H O, being 
analogous to sulphuric ether, which consists 
of 2 atoms olefiant gas. The nature of its 
function may be observed in the composition 
of the common sulphate of copper and am- 
moniacal copper, the first is Cu S H -{- H 4^ 
the second Cu S .H (N- H3) 4 the ammonia 
taking the place of the water. There are 2 
ammoniurets, 1 containing 4 and the other 5 
atoms of water. 
