344 The Lambeth Observatory. [July, 



Survey ; and these practical authorities pronounced that the pro- 

 posal was sound in principle, and likely to he efficient in operation. 

 The order was then issued that the observatory should he con- 

 structed ; and the construction, and subsequent management of the 

 establishment, were placed in the hands of the designer, Colonel 

 Strange, who in addition to a natural taste for, and capabilities of, 

 dealing with delicate and fine mechanism, had enjoyed the field ex- 

 perience of thirteen years of service upon the great trigonometrical 

 survey of India. 



The first matter that had to be decided in connection with this 

 design was the place where the fixed obseiwatory could be planted. 

 Up to this time all instrumental examinations had been made in 

 the old building that had been used as the Indian store, and that 

 stood opposite to the ancient Company's " House " in Leadenhall 

 Street. It therefore was deemed only natural that the instruments 

 should follow the store, and that the observatory should be planted 

 on the ground acquu'ed by the department in Lambeth ; the site 

 was obviously not the best in the world for the purpose, but as no 

 other available position could on the instant be fixed upon, it was 

 ultimately resolved to do the best that could be done in connection 

 with the Lambeth store, and the existing observatory was com- 

 menced in the year 1865. 



The earhest proceeding was necessarily to neutralize the natural 

 unfitness of the ground and position for exact instrumental work, 

 so far as this could be done. This has been most admii-ably and 

 most efficiently accomplished, and as follows : — First, twelve iron 

 screw-shod piles with the widest part of the spiral thread 2 feet in 

 diameter were wormed into the gravel, which here lies 24 feet 

 below the sm'face of the ground. Broad heads of cast iron were 

 next keyed upon the top of the piles. Thick slabs of flag-stone 

 were then laid upon the pile-heads, and the space beneath filled in 

 with concrete cement to the depth of about three feet. A circular 

 platform of brickwork was finally constructed upon the flag-stones, 

 and upon this, two semicircular segments of waU were reared 

 round the circumference, and a sohd pedestal of masonry was 

 erected in the centre. This circle of wall, cut by two gaps at 

 opposite points of the circle, and this enclosed central pedestal are 

 the objects which now form the visible base of the observatory, and 

 which carry the chief instruments employed in the scrutiny. A 

 wooden platform, or floor, between the circular wall and the central 

 pillar, to which access is obtained through the gaps, is carried upon 

 Ijeams that are sujiported from beyond the system of pile-work, 

 and is carefully isolated from all mechanical connection with the 

 piled foundation, so that the observer moves about upon this floor 

 without eff'ecting any disturbance in the position of the instruments 

 carried upon the walls and the pedestal. This method of seeming 



