194 REPORT — 1861. 



■ Your Committee would again call the attention of shipowners to the system 

 of trials which has resulted in the combination of perfect regularity and effi- 

 ciency of service with economy (so far as the vessels and machinery would 

 admit) which this series of returns exhibits. 



In the first Report of this Committee, presented to your Association at the 

 Meeting held in Aberdeen, a series of tables are given, showing the method 

 which was adopted for ascertaining the working capabilities of each vessel. 

 The following explanation was furnished by Admiral Moorsom, and illustrates 

 the means by which the proper service to be obtained from a vessel may be 

 estimated* : — 



" When the four passenger vessels, ' Anglia,' ' Cambria,' ' Hibernia,' and 

 ' Scotia,' were first employed in August 1848, the commanders were autho- 

 rized to drive them as hard as they could, subject only to the injunction not 

 to incur danger." 



After some months' trial the qualities of each vessel and her engines were 

 ascertained, and a system was brought into operation which continues to the 

 present time. (Tables 3-14.) 



The Returns Nos. 2 and 6 show the results of the hard driving and the 

 commencement of the system periods. The column indicating " Time," 

 " Pressure," and " Expansion," is the key to the columns "Average Time of 

 Passage," "Weight on Safety Valves," and "Proportion of Steam in Cylin- 

 der," and, as a sequence, also to the consumption of coal. 



" Time a minimum " shows the hard driving. " Time a constant " shows 

 the system. The relations of " pressure " and " expansion " show how, under 

 hard driving, the highest pressure and the full cylinder produced the highest 

 speed the wind and tide admitted, or how, the time being a constant, those 

 two elements were varied at the discretion of the commander, within prescribed 

 limits, to meet the conditions of wind and tide. 



The result of the system on the coal is a decreasing consumption. 



The Return No. 1 shows the results of certain trials under favourable con- 

 ditions, but in the performance of the daily passage by four of the vessels, 

 which results are used as the standard tests with which the results of each 

 quarter's returns are compared. 



For example, the, ' Scotia ' at 15-9 statute miles an hour consumes 6840 

 lbs. of coal as a standard. (See Table 4.) 



In the Return No. 3, at the speed of 12-96 miles she consumed 5226 lbs. ; 

 the first at the rate of 430 lbs. per mile (see Table 5), and the second at 

 about 403. 



Again, in the succeeding quarter, the ' Scotia ' consumed 7528 lbs. at 

 14'65 miles an hour, or more than 513 lbs. per mile. 



Here was a case for inquiry and explanation. It will be observed that in 

 Return No. 1 the consumption of the ' Scotia ' at ordinary work at sea is 

 5820 lbs. per hour, and it is only when the consumption exceeds 6840 lbs. 

 that it becomes a subject of question, the difference between those figures 

 being allowed for contingencies. 



No. 4 (see Tables 12, 13) is a Return which shows the difference between 

 the issues of coal each half year, and the aggregate of the returns of con- 

 sumption, the object of which needs no elucidation. ^ 



No. 5 (see Table 14) shows the duration of the boilers, with particulars of 

 the work done. The saving in money under the return system, as compared 

 with hard driving, was of course very considerable, and the latter was only 

 justifiable as a necessary means of learning the qualities of each vessel, to be 

 afterwards redeemed by the economy of the system. 



Tlie ' Kibernia,' it will be seen, was unequal to the service ; and I may 

 * See Volume of Transactions of the Aberdeen Meeting, 1859, page 276. 



