ON RAILWAY BAR CORROSION. 99 
Taste No. 2.—Second set of Experiments on the Dublin and Kingstown Rail- 
way: rails traversed from Oct. 18, 1842 to Oct. 18, 1844: period 730 days. 



Po g Weights of G ‘ht! First dif-|Second dif. 
BY | our exposed, (amish, of ratte weigh-(Oraeywaaht or the act. | opeeigat | ference | =a. be 
q BY &e. a eg together ed together | when laid | When re- ineach |=Corro-| tween cor. 
A g when exposed. pene amore down. marek head set. ge ty age ont 
ewt grs. {cwt grs grs gTs grs, grs grs 
op eee No. al 6-429,750| 6-421,875 
At one side | 
‘| of line © J 
- |nottravelled | 
over. 
ie Picreeion 6+47,250| 6+42,000 
ee MORE 6 TY ir sda 9,485,000 | 9,471,875 | 13,125...|......... 7 
Set No. 2. | 
+] 6422,750| 6— 3,500 
On the East | 
“| side of the J { 
Up Line : 
F ee 
Pisce 6+-77,875 | 64-51°625 8312 
Hh Abraniors 
ee, heart! Hts aechoasuewass o)scagnsasW et vas 9,508,625 | 9,456,125 ae 
> | Set No. setes]| | 
. | side of Up 
“<9 pee J 4813 | J 
% 4 
* |Coal-tarred. 
Bes Abiaains 6+27,125| 6+ 2,188 
mp, ly | Re 4 | eS age a 9,458,312 | 9,410,625 | 47,687 

From these results we learn, that in a period of 730 days’ exposure,— 
1st. The absolute abrasion from traffic on the six rails was 47,687 grs. avoir. 
Qnd. The absolute corrosion of the six rails in use, or exposed to traffic 
and to corrosion, was 4813 grs. avoir. 
$rd. The ratio of abrasion to corrosion on the rails in use is therefore nearly 
in the ratio of 47-7 to 4°8, or in round numbers as 48 to 5, or nearly 10 to 1. 
. _ 4th. The absolute corrosion of the six rails out of use, or not travelled 
‘over, was 13,125 grs. avoir. 
5th. The ratio of the abrasion of the rails in use to the corrosion of the 
__ rails out of use is nearly as 47°7 to 13°1, or in round numbers about as 4 to J. 
6th. The difference (absolute) between the corrosion of the rails in use 
and out of use is =8312 grs. avoir. Hence 
- "th. The ratio of the corrosion of the rails in use is to that of the rails out 
x of use as 48°13 to 83°12, or in round numbers as 8 to 14. 
H2 
