1314.1 Scientific Intelligence. 233 



details of the experiments are not given, we have no means of 

 judging how far they may be confided in. 



IV. New Acid. 

 Gay-Lussac has finished a very laborious and complete investiga- 

 tion of the properties of iodine. During his experiments he disco- 

 vered that chlorine has the property of combining in two proportions 

 with oxygen, and of forming two acids, which he calls the chloric 

 and chlorous acids. The euchlorine of Davy is Gay-Lussac's 

 chlorous acid ; but it would seem that the chloric acid is the more 

 curious and important compound. I have not heard how it is 

 obtained ; but as soon as the facts are transmitted to us from Paris, 

 I shall lay them before my readers. 



V. New Experiments on the Velocity of Sound suggested. 

 I insert the following valuable letter just as I received it ; — 



(To Dr. Thomson.) 

 " MY DEAR SIR, 



" It has frequently excited my surprise, as well as regret, and in 

 which I am nowise singular, that use has not been made of the 

 admirable trigonometrical survey begun by the late General Roy, 

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

 and Professor Dalby, to make experiments on the velocity of sound: 

 and however experiments of this kind may have been neglected, it 

 is to be hoped that the present Master General of the Ordnance, a 

 Dear relation of the late scientific Capt. Phipps (afterwards Lord 

 Mulgrave), so much celebrated for his voyage towards the North 

 Pole, 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. These experiments it would be 

 advisable to make under a variety of circumstances; for instance, 

 in cold and dry weather; in windy and calm weather; in the day 

 time, as well as in the night ; on those days when the air is found 



e verj i lastic, as well as when the atmosphere is found not so 

 well adapted for transmitting sound; also with heavy and light 

 piecei of ordnance. The places on the coast selected for this pur- 



• might be Dover Castle, Fair Leigh, Bpachey Head, Dunnose; 

 and in the inlai d parts, which are near the metropolis, perhaps 

 none i- better situated than Lady James's Tower at Shooter's Mill; 

 the facility with which observers can accurately determine the 

 distance or their stations, by taking the angles of the different 

 churches and other objects, renders this spot peculiarly eligible ; 

 and it notiee was given of the day on which the experiments were 

 to be made, many philosophical gentlemen would lend their assist- 

 anec ; and ai t lit- pocket chronometers generally make five heats in 

 two seconds of time, the velocity of iiouud would be determined to 



