194 REPORT — 1864. 



made in the past year, with the exception of preparing an instrument and 

 apparatus for the investigation. 



At the request of the Committee Mr. Flecming Jenkin kindly undertook 

 to superintend the construction of the instrument best adapted for the purpose, 

 but it unfortunately happens that no flame or fire of any kind can be admitted 

 into the car of the balloon for fear of igniting the gas, and this instrument, 

 Avhich was furnished a little before the end of the year 1863, was constructed 

 to be used with fire. It therefore had to be altered so that it covild be used 

 with water, but is not yet quite in a state for observation. 



It happens unfortunately that electrical experiments in balloons necessitate 

 the use of one constant flow of water, and occasionally of two flowing at the 

 same time, just below the car of the balloon. 



The Committee felt that the presence of water but little removed from 

 the instruments, if exercising no influence when the balloon was rising, 

 might exercise such an influence on the balloon falling and passing through 

 the just moistened atmosphere as to throw a very considerable doubt on 

 some of the experiments, particularly on those relating to the hxmiidity of 

 the air (a primary object of research), that I was requested to defer taking 

 them, that no doubt might rest on the results, till our knowledge on this 

 subject was much increased. 



The Committee consider that the general laws on the humidity of the air 

 have now so advanced, that electrical experiments may now be included, 

 providing that such observations can be made with safety to ourselves. 



With respect to the second of these objects, viz. verifying the law of the 

 decrease of temperature in different states of the atmosphere. The Committee 

 considered that this would be best attained by taking as many observations 

 as possible, at times in the year and at times in the day at which no experi- 

 ments had been made, for the purpose of determining whether the laivs which 

 hold good at one time in the year, hold good at other times in the year, and 

 also to determine whether the laws which hold good at noon, apply equally 

 well at all other times in the day. 



The Committee at all times have pressed on me the importance of magnetic 

 observations in the higher regions of the atmosphere, the Astronomer Eoyal 

 suggesting the use of a horizontal magnet, and taking the times of its vibra- 

 tion at different elevations, a method which is seldom practicable, owing to 

 the balloon almost constantly revolving on its own axis. To obviate the 

 effect of this, Dr. Lloyd suggested the use of a dipping-needle placed 

 horizontal when on the ground by means of a magnet adjustible above it, so 

 that when in the balloon the deviation from horizontality might be readily 

 noticed, and which deviation would be independent of the revolving motion 

 of the balloon, and could thus be noticed at any instant. 



I have been unable to attempt the latter method, as Dr. Lloyd wished some 

 experiments to be made before the instrument should be constructed. 



At Newcastle a very general wish was expressed by the Members of 

 the Council that I should not ascend to heights exceeding 4 or 5 miles. To 

 this I readily consented, because for the most part, from the preceding experi- 

 ments, aU the observations above 5 miles could have been inferred from those 

 made below 5 miles ; and there was another reason, that the balloon, after 

 the many rough descents, had become, in Mr. CoxweU's opinion, too unsafe 

 for exti'eme high ascents. 



I have therefore no report to give upon any extreme high elevation 

 attained during the past year, yet new facts and new physical conditions 

 have become known in some of the nine ascents upon which I have to speak. 



