674 ME. MALLET ON THE TEANSIT-VELOCITT OF EAETHQHAKE WAVES. 
There are four corrections altogether applicable to the uncorrected transit-rates, 
col. 8, Table I., as already referred to, viz. — 
1st. That for the liquid wave in the seismoscope, which, as a delay in time^ is, 
when converted into distance, always This correction has been already applied 
in cols. 9 and 10, Table I. 
2ndly. That for the time of hang-fire of each explosion in the rock ; the constant 
in time for which has been given =0"-056. 
It appeared, however, uncertain whether this should be converted into distance, as pro- 
bably nearly constant for every experiment, or in what way it might be variable, in 
relation to the weight of powder and other circumstances of each. The result disclosed 
in Table II., however, appears to indicate that the conversion into distance should be 
proportionate to the respective gross or uncorrected transit-rates, assuming, as we may 
now do, that these are functions of the originating impulses and resistances together, 
in each instance. This may not be absolutely true, but is the nearest approximation 
we can make. This correction in distance is also always +. 
Srdly. The loss of time at making contact, — whether galvanically, in which we 
ascertained the constant in time to be =0"-0143, when converted into, distance 
always ; or by the hand (of the firing party), when we found it was in time 
= 0"-013, which in distance might be either -j- or — . 
The probability being so much in favour of the latter being positive, I have ventured to 
apply it as always so, which also renders all the experiments more truly comparable, 
4thly. The personal equations of the observer and time of transit of the galvanic 
current, both of which may be neglected. 
Applying these several corrections, we obtain the following Table and final numerical 
results : — 
Table III. — Wave-Transit Experiments, Corrected Eesults. 
1. 
2. 
3. 
4. 
5. 
Xumber of 
experiment. 
Observed rate of 
transit per seeond, 
uncorrected, 
col. 8, Tab. I. 
2nd correction, 
for hang-fire 
of explosion taken 
in distance. 
Transit-rate with 
2nd correction, 
col. 2 -j- col. 10, 
Tab. I. 
3rd correction, 
making contact, 
into distance. 
Final corrected 
transit-rates, 
col. 3 -f- col. 4. 
1. 
feet per second. 
896-12 
feet per second. 
50-183 
feet per second. 
1004-551 
feet per second. 
11-649 
feet per second. 
1016-200 
2. 
967-93 
54-204 
1085-119 
13-831 
1098-950 
3. 
977-26 
54-726 
1095-508 
13-975 
1109-483 
4. 
1173-87 
65-737 
1315-908 
15-260 
1331-168 
5. 
1210-79 
67-804 
1357-295 
15-740 
1373-035 
6. 
996-11 
55-792 
1116-649 
12-949 
1129-598 
The limits of error in these results would seem to be, that the 2nd correction raay 
amount to 15 -5 feet per second in excess, and the error from all other instrumental or 
observational sources may be estimated probably at not more than 10 feet per second, so 
that the results may be deemed true to within 25-2^ feet per second + or — . 
The general mean derivable from the whole of the experiments taken together gives 
