498 Mr. G. Walker on the moving the Knight over 
No. 
Fluids of the degrees of con- 
centration mentioned. 
Amalg. 
of 
Zinc. 
Platina. 
Amalg. 
of 
Zinc. 
Silver. 
Amalg. 
of 
Zinc. 
Copper. 
Amalg. 
of 
Zinc. 
Tin. 
Amalg. 
of 
Zinc. 
Iron. 
Amalg. 
of Zinc, 
distilled 
Zinc. 
37 
Ammonia (a) 
Water (w) 
a>^w 
a <cw 
a>w 
a:z> w 
a>-w 
38 
Sulphuric acid (5f) 
Iodide of potassium (i) 
s < z 
s>- i 
sci 
sci 
s>-i 
s < 4’ 
s:z^i 
39 
Hydrochloric acid (s) 
Iodide of potassium (i) 
s<z,i 
s>i 
s ci 
sc:i 
5 > 4 
s<ci 
s> i 
37. With 'platina, copper, and zinc feeble, stronger with silver, still stronger 
with tin, and exceedingly strong with iron. 
38. Even with non^ieated platina the s -< i powerful. The i also strong 
with silver and copper, less so the s c i with tin. With iron the action ex- 
ceedingly energetic, first a deflection of 40° in the direction s c i, immediately 
succeeded by one of 90° and oscillations between 90° and 80° in the direction 
s > i. — With just the same, the first deflection in the direction = 90°, 
the second in the direction s > i = 90° followed by oscillations between 
+ 90 and -h 75°. 
39. Even with non-heated platina s < * powerful, with it at least no rever- 
sion. With silver and copper action very strong. — With tin the s> i weak, 
slowly, and especially after repeated immersion passing into s -c. i. — With 
iron only the first deflection of 60° to 70° in the direction s < «, the second 
immediately in the direction s > i = 90°, then- oscillations from + 90° to 
+ 80°. — With zinc precisely the same. 
A careful glance at the facts contained in these Tables will 
justify the correctness of the positions above advanced. I will 
here draw attention to some distinct cases which will establish 
them more perfectly. 
[To be continued.] 
LXXV. On the moving the Knight over every Square of the 
Chess-board alternately. By George Walker, Author of 
various Works on Chess ; and Honorary Secretary of the St, 
George’s Chess Club, 
To the Editors of the Philosophical Magazine and Journal, 
Gentlemen, 
VT OUR Number for the present month has just come into my 
hands, and I find it contains an interesting paper upon the 
knight’s move, by Dr. Roget, to which my attention is particu- 
larly drawn, from the circumstance of that essay having, it ap- 
pears, been suggested by one of my chess articles in Fraser’s Ma- 
gazine (see Fraser of March 1840.). In that memoir, the sub- 
ject of the knight’s circuitous leap was merely touched upon en 
