96 -  REPORT—1849. 
Tasce B. deduced from Mr. Godwin’s Experiments on the Ulster Line, laid down 
June 15, 1842, removed June 27, 1843: period 377 days. 








3 in veri kG ight |G iett| Total Jee eee ee 
2 ight t TOSS Wel Toss Wel, 0 OSs = 
g Mark. | How exposed. whet ei panes when Tad sa of weight in penesacem tween cor. 
posed of moved of down. removed. | each set. in use, | im use and 
each rail. each rail. out of use, 
\él2| 3 |Zlel2] ‘ grs. grs. grs. 
1] © | Set No.1. |2|3/22] 33/2}3 191/15 |s, SPsnde sain 
2| B. | Between the |2|3/19) 83/2|3|19| 73\Nere coated by 
3 rails © not |2/3 |22) 4 |2/3(/21) 0 we must’ double 
4 travelled over.| 2 |3 |27|} 33/2] 3 |27| 32lan approximate 
5 Corrosion |2|3/19| 3 |2/3]19| 3 jresutt- Albs. 30z. 
6 alone. 2{3|19| 9 |}2/3|19| 1 | 17.2.17.153/17.2.15.14 | =29,312 |....... Anee 
1] ©© | get No.2 2\|2 18/15 2) 2/17/12 
2 Exseied t6 3 |12)153| 2|3 11} 6 
3 759 a 3|27|11 |2)3|25| 0 
4 eee. 3] 1/103/213| 0) 6 
5 Wicoatd 2/3|17|15 | 2| 3 |15|12 11 bs. 
6 neoated. | 9/3 \92| 7 |2|3|20| 6 |17.0.17.10 |17.0. 6.10} =77,000 |} 
1|000 2/3 \20| 7 |2|3\19| 2 
3 ~ 1213)19) 9 |}2)3)19 48,344 
‘ traffic ereaion 213\20| 5 |213/20| 2 u 
5 Pitan 9 2/3/25] 53/2] 3 25] 0 Albs. 1 40z. 
6 ated. | 2/3 [21] 53|2|3 |20| 8 | 17.2.17. 93|17.2.13. 8 | =28,656 

On examining this Table B, it appears that— 
1. The absolute loss from abrasion only is=28,656 grs. 
2. The absolute loss from corrosion only is=29,312 grs. on the rails not 
travelled over; and 
3. The absolute loss from corrosion only is=48,344 grs. on the rails ex- 
posed to wear of traffic. 
Hence in this case the corrosion of the rails out of use is less than that 
of the rails in use in the ratio, in round numbers, of 29°3 to 48°3, contrary to 
the received notion. 
As doubt rested on these results, owing to the circumstances already 
detailed, I determined to lay down a fresh set of prepared rails upon the 
Kingstown Railway, and subsequently another set upon the Dalkey Atmo- 
spheric Line, which, being a single line, stood in the same predicament as 
the Ulster Railway. 
One of the greatest difficulties attending experiments of this character, 
consists in the extremely small amount of weight to be determined (namely, 
the small loss by corrosion, even in a prolonged period), compared with the 
weight of the rails themselves, and the great absolute weight of the latter 
demanding balances of great strength, which are very difficult to be given 
the requisite sensibility. Where balances only competent to weigh one length 
of rail at a time are used, as in the case of Experiment No. 1, then the 
several sources of inaccuracy in each operation of weighing are multiplied — 
by the number of rails weighed. As, therefore, the error of large balances 
does not increase quite as fast as the size of the instrument is magnified, it 
appeared advisable to obtain means of weighing several lengths of rails at 
once or together; and for this purpose new standard weights were required, 
as well as new balances. 
The standard, namely, a brass authorized copy of the standard 56lbs 
weight, in the custody of the Corporation of Dublin, which is under- 
stood to be a true duplicate of that formerly in the Exchequer Office, 
