11 



It also exemplifies Boileau's constant activity of mind, that he 

 published, at this early date, a report of his own " On the Practica- 

 bility and Expense of a Plan proposed for Constructing Docks in 

 Diamond Harbour on the River Hooghly, and for uniting them 

 with Calcutta by a Railroad, together with an Estimate for the 

 same." 



It was at this time that the interest of the Royal Society in 

 magnetic observation, which had been originally stimulated in 1836 

 by. a letter of Humboldt's to the then President (the Duke of 

 Sussex), and had been maintained by the zeal of Major Sabine, 

 was at its height. The Society recommended the Court of Direc- 

 tors of the E.I. Company to take part in the institution of mag- 

 netic and meteorological observations, which (chiefly through the 

 influence of Colonel Sykes) they decided to do. Boileau and two 

 officers of the Madras Engineers, Lieutenants Ludlow and Elliott, 

 were appointed to establish and take charge of observatories at Simla, 

 Madras, and Singapore respectively, and all three went to Dublin in 

 November, 1839, to receive from the late Rev. Dr. Humphrey Lloyd, of 

 Trinity College, a course of that preparation for their duties which 

 that eminent philosopher alone could then impart. Captain Boileau, 

 before he left again for India, was elected a Fellow of the Royal 

 Society, and also a Fellow of the Royal Astronomical Society. 



The three Indian Engineer officers embarked in February 1810 

 for Madras, reaching that port in June, where they separated, and 

 Boileau with his instruments proceeded to Calcutta. He reached 

 Simla on the 24th of September, some weeks before the arrival of 

 his assistants with the instruments. He had taken observations of 

 dip on his palankin journey, by the way, at Allahabad, Futtehgurh, 

 Bulandshahr, Karnal, Ambala, and Bar (at the foot of the hills on the 

 road to Simla) . He was also fortunate in securing for his niagnetical 

 campaign the hearty interest of the Rev. John Henry Pratt, after- 

 wards Archdeacon of Calcutta, a man not less well known for his 

 scientific acquirements than beloved for his character. 



Captain Boileau selected for his observatory a site on what was then 

 called Bentinck Hill, but which has since been known as Observatory 

 Hill, and which in the rapid revolution of administrative events in 



village lands by the officers of the Government Revenue Survey, and have gone 

 through several editions. They are the first ever published for angular values to 

 single minutes of arc, or to five places of decimals for distances. Their great 

 utility, both for the above purposes and for surveying in general, has been acknow- 

 ledged by letters from the United States of America, from the Brazils, from Australia, 

 and from India." Boileau's tables are in habitual use at Cooper's Hill College. 

 Traverse tables are intended to save the calculations of triangles in ordinary surveys, 

 by showing by inspection the amount in linear measurement of the difference of lati- 

 tude and departure (i.e., of longitude) for any bearing and distance. 



