352 Professor Forses’s Researches on Heat. 
is concave to the axis, or the Statical effect increases in a less ra- 
tio than the Dynamical effect. The convexity of the one curve, 
almost compensating the concavity of the other, the relation ob- 
tained between the first impulsive arc and the calorific force, is 
nearly linear. 
11. This will be best illustrated by comparing the true ratios 
of the forces obtained from the above table, with the simple ratio 
of the first deviations ; and to put it in greater evidence we shall 
suppose a deviation of 20°, which is greater than we have ever 
employed in these experiments. 
First Deviations compared. Ratio. Ratio of Intensities. 
20° and 1° -050 .049 
20 — 2 -100 097 
20 — 4 -200 91 
20 — 8 400 395 
20 — 12 .600 593 
20 — 16 .800 796 
Since, therefore, even in this case, we should never have an er- 
ror amounting to a unitin the second decimal place, I have con- 
tented myself in this paper with the employment of the simple 
arithmetical ratio of the first ares passed over. 
12. The construction of the table in Art. 8. was attended 
with much more trouble than I anticipated. ‘The relation be- 
tween the Dynamical and Statical effects appears to depend up- 
on circumstances very easily overlooked. Comparisons repeated 
apparently under the same circumstances often differ very mate- 
rially, relatively to the magnitude of the quantity sought, name- 
ly, the difference of the two effects, which is always small. This 
seems chiefly to depend upon the condition of the conducting 
wire which has transmitted the electric current. It is well 
known, that such wires retain for some time the molecular con- 
dition, into which they have been thrown, by transmitting elec- 
tricity, even after the current has ceased. This may be expected 
perhaps to be even more strongly the case in electricity of small 
