172 Mr. M. Ponton on certain Laws 
H near G, so that the first is the abnormal node. The transfer 
of energy takes place from C and H to B, D, E, F, and G. 
Muriatice acid has four nodes—between B and C, C and D, 
D and £, F andG, the transfer of energy being from B, D, G, H 
to C, E, F. 
Solution of soda presents also four nodes—between B and C, 
Cand D, Eand F, Gand H. The transfer of energy is from 
BDEH toCFG. 
Sulphuric acid has no less than five nodes—between B and C, 
D and BE, Eand F, FandG, Gand H. The transfer of energy 
is from BEG to CDFH. This medium has the smallest 
amount of extrusive power of any yet examined. 
It would be well to have the observations on these eight media 
carefully repeated, in order to ascertain how far these peculiari- 
ties, or any of them, may be due to serious errors of observation, — 
a supposition which will in the sequel be shown to be very highly 
probable. At the same time it would be difficult to assign any 
reason why such peculiarities should not exist, or why all media 
whatever should conform to one uniform type. 
Meanwhile, assuming the observations to be nearly correct, it 
is needful to point out the changes which these several peculiari- 
ties introduce into the laws before indicated. 
Ist. The law of equal transference subsists unaltered. 
2nd. The semel-bis-ter law undergoes the followmg modifi- 
cations. The regular type being 
Bb, + 2¢,—d,=Bhy + 292— fr 
it becomes in high nodal media, 
3b; —2c,—d,=8h, + 292 —fr3 
in low nodal media, 
3b, + 2¢,—d,=8h,—29.—fr 5 
in pyroligneous acid, 
—3b;+ 2¢c,—d,=8h,—29.—f; 5 
in muriatic acid, 
3b,—2c,+dr=8hp+ 292—fe5 
in solution of soda, 
3b,—2c, +d,=8hz—2G2—fe 5 
in sulphuric acid, 
8b, —2¢,—d,= — 3h, + 2G2—fe- 
Hence the general expression for this law must be 
+86, + 2c, +d,= +3h, +292 +fe 
3rd. As respects the law of the equicentral common difference, 
one general rule will suffice. Where the pairs 5, and h,, c, and 
