TRANSACTIONS OF SECTION A. 79.7 



an ordinary burnino: glass or photographic record, is very clearly shown. It is 

 also found that, when the sky is obscured by clouds of sufficient thickness to 

 prevent any trace of burning on the ordinary cards, a very considerable percentage 

 of the sun's heat may still penetrate. 



The recording apparatus used is identical with that required for records of 

 temperature, pressure, voltage, &c., and may be located in any convenient situation, 

 at any required distance from the bolometer. It has been in use for more than a 

 year at McGill College, Montreal, for obtaining records of sunshine, temperature, 

 &c., and has been in regular operation at a distance of more than a mile from the 

 observatory, where the recording apparatus is kept under the charge of the usual 

 observatory assistants. 



A simple form of planimeter is attached to the instrument when used for 

 recording sunshine. The reading of the planimeter gives directly at any time the 

 total quantity of heat received, and can be readily reduced to the number of 

 equivalent hours of ' bright sunshine ' by means of a suitable factor. 



(The apparatus was exhibited in action, together with specimen records, and 

 two illustrative lantern-slides.) 



6. Progress in the Exploration of the Air by means of Kites at Blue Hill 

 Observatory, Massachusetts, U.S.A. By A. Lawrence Rotch, S.B.y 

 A.M., Director. 



Since the report was presented to the Toronto Meeting of the Association Teat 

 progress has been made in the work. The Ilargrave Kite has been perfected by 

 making it larger, more rigid, and relatively lighter, and by concaving the surfaces 

 exposed to the wind the vertical component of the latter is increased. In general, 

 these kites, wath a short line, rise from oO° to 60° above the horizon and pull about 

 one pound per square foot of lifting surface in a wind blowing 20 miles per hour. 

 Elastic bridles diminish the angle of incidence of the wind as its pressure increases, 

 and thereby enable the kites to fly in gales. A meteorograph, made by Mr. Fer- 

 gusson, of the Observatory staff", which records the pressure of the atmosphere, the 

 temperature, and relative humidity of the air and the velocity of the wind, weighs 

 but 3 lbs. Since the use of wire and more efficient kites the mean height of the 

 flights has been increased from about 1,000 feet in 1896 to above 7,000 feet during 

 the past few months, and the height of 10,000 feet has six times been exceeded. 

 The meteorograph reached an altitude of 11,086 feet above the hill in October 

 1897,' and its maximum altitude of 11,440 feet on August 20, 1898. A descrip- 

 tion of the apparatus employed and a discussion by Mr. Clayton, of the meteoro- 

 logical records obtained until February 1897, were published this year as an Appen- 

 dix to the Blue Hill observations for 1896, in the 'Annals of the Astronomical 

 Observatory of Harvard College,' vol. xlii, part 1. It is expected that the final 

 discussion will be published by the Smithsonian Institution. In consequence of my 

 report to the International Aeronautical Conference at Strasburg in April 1898, 

 it was recommended that all central observatories should employ this method of in- 

 vestigation as being of prime importance for the advancement of meteorological 

 knowledge. 



7. A New Form of American Kite. By Piofessor A. Schuster, F.R.S. 



8. Analogies between the Yearly Ranges of some Meteorological and Magnetic 

 Phenomena. By Dr. vax Rijckevorsel. 



This is the second part of a paper read at tlie Toronto meeting, in which it 

 was shown how exactly similar the yearly temperature curves are for a large part 



' See Nature, November IS. ISDT, and February 17, 1898. 



