1826.] of the Length of the Pendulum alike Equator, 28§ 



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return voyage to Madras, for obtaining hiucIi valuable nautical 

 information ; and no such opportunities should be allowed to 

 escape. ^ ^ . 



" The party will first proceed to Bencoolen> where Sir Ststfli- 

 ford Raffles has promised to furnish any additional assistance 

 that may be required — a vessel to proceed to the Equator, a 

 guard, materials (bricks and lime), and a bricklayer or two -to 

 build a pillar, to which to fix the clock ; two carpenters ; and 

 provisions ; comprise the principal assistance wanted, A 

 watch-maker to put up the clock may be required ; ^but^ii'Will 

 be better, if possible, to do without one. ■ 



'* On arriving at Bencoolen, observations should be taken for 

 the time, for the purpose of obtaining the difference of longitude 

 between Madras and that place : these observations should be 

 continued for the rates of the chronometers, and a fresh depar- 

 ture taken from Bencoolen, for the longitude of the place where 

 the experiments with the pendulum are to be made. Observa- 

 tions should also be taken for the latitude of Bencoolen, the 

 variation of the compass, and, if possible, the rise and fall of the 

 tide, with the time of high-water at the full and change. 



" In selecting a station at the Equator, care should be taken 

 that it be as far as possible out of the sphere of the attraction 

 of mountains, and close to the sea — a small healthy island, at a 

 moderate distance from the main land, would be a most desira- 

 ble place for a station. There is an island (Saka) on the Equa- 

 tor; this, however, is a long way out ; and unless there be a 

 post on Po. Pinjin, it may be at an inconvenient distance from, 

 .the Sumatran shore : some healthy island may probably be iiM 

 with nearer the coast. ^ ^ '- 



f^f Having found the Equator by observation, the pillar is to lie 

 erected upon it.* The face should be perfectly flat and upright^ 

 and should front the opposite part of the horizon to that the 

 wind of the season blows from ; if it be the south-west monsoon, 

 for example, the face of the pillar should be to the north-east ; 

 while the pillar is building, the plugs of wood for fixing the 

 frame, which is to support the pendulum of experiment, should 

 be inserted, exactly in the proper places, as well as the plugs 

 for fixing the plank to which the clock is to be attached : small 

 pieces of wood should also be placed in the projecting part of 

 the pillar on which the clock, and the stand for the arc for 

 measuring the vibrations of the pendulum of experiment, are to 

 rest ; to those pieces of wood is to be screwed the stand just 

 mentio^^(^, J ^.yl^eft^yi^, pillar shall have properly settled, and 



* The pillar ta be commenced as early as practicable, and to be -Icept 'iVoni'raii^ lyyk 

 tarpaulin^ the object being to have it as dry as possible before the clock and frame aire 

 put up. It is not to be plastered, as that would keep it wet a very long time — strong 

 cement that will soon set, to be made use of, if to be obtained — as little water as possi- 

 ble to be used in mixing the chunam, and laying the bricks. 



New Series, \ Oh, xu, v 



