202 Mr, Goldingham on the Velocity of Sound. [Sept. 



the admirable Trigonometrical Survey, begun by the late Gen. 

 Roy, and continued with so much ability and attention by Col. 

 Mudge and Prof. Dalby, to make experiments on the velocity of 

 sound ; and however experiments of this kind may have been 

 neglected, it is hoped that the present Master General of the 

 Ordnance, a near relation of the late scientific Capt. Phipps 

 (afterwards Lord Mulgrave) will, for the purpose of perfecting a 

 branch of science, no less curious than useful, order a series of 

 experiments of this nature to be undertaken, not only in the 

 inland parts of the kingdom, but also on different parts of the 

 Coast." He then mentions that the experiments should be 

 made under different circumstances of the wind and wea- 

 ther, and at different times of the 24 hours, and proceeds ta 

 enumerate the stations where the experiments should be made. 

 He recommends that pocket chronometers should be used, 

 ' which, generally, making five beats in two seconds, the velo- 

 city of sound could be determined to the fraction of a second ; ' 

 and concludes by saying, * he has no doubt scientific foreigners 

 would assist our countrymen in finding the time sound is travel- 

 ling across that part of the Channel, where the shores are visible 

 from each other."* 



At Fort St. George (Madras) a morning and an evening gun 

 are fired from the ramparts, as is customary in fortified places, 

 the former at day hght, and the latter at eight o'clock in the 

 evening. At St. Thomas's Mount, the artillery cantonment, 

 morning and evening guns are also fired, one at day hght, and 

 the other at sun set. The Madras Observatory, in latitude 

 13° 4' 8'^ north, is situated between these ; the distance of it 

 from the Fort, about half its distance from the Mount, the Fort 

 being to the NE of the Observatory, and tlie Mount to the 

 SVV. In former years, as I have mentioned before, experiments 

 were made by me for ascertaining the velocity of sound, but were 

 not brought forward. And a new bailding,t elevated so as to 

 give a commanding view of the country, particularly of the 

 Mount f and Fort,§ having been erected, I commenced a new 

 series with the morning and evening guns of both places. The 

 experiments with the Mount gun, it will be seen, comprise an 

 interval, which embraces all the varieties of the wind and weather 

 during the revolution of the sun ; the interval with the Fort gun 

 is less, in consequence of the morning and evening guns having 

 been fired from different parts of the ramparts, after the date at 

 which the Fort experiments close. All the experiments were 

 made with chronometers, which had 100 beats in 40 seconds, 

 sometimes by three observers, myself and two of the Observa- 

 tory Bramin assistants, but generally by two: the observers 



• Annah, O. S. iv. 233. 



•f- The station on this building is about 55 feet above the level of the sea, distant in a 

 direct line 4500 yards. 



X The Mount gun is about 120 feet above the level of the sea. 

 § The Fort gun is about 30 feet above the level of the sea. 



