67 



sunshine, etc. Concerning the origin of the complicated and ever- 

 changing system of atmospheric phenomena much has yet to be 

 learned, but the circulation set up by the unequal heating of the 

 atmosphere by the sun and modified by the earth's axial rotation is 

 doubtless the chief factor. Our peculiar English weather is largely 

 dependent on the fact that these islands lie in the favourite track of 

 cyclones. Besides the indications of the barometer other means of 

 forecasting weather are of some importance, for example, the careful 

 study of cloud-forms and cloud-movements. 



Observational ^ ^ ecture navm g this title was given on February 

 . 23rd, by E. W. Barlow, Esq., f.r.a.s. The 



lecturer began with the statement that in spite of 

 the multiplication of large telescopes and of observatories with 

 elaborate accessories, good and useful work could still be done by 

 amateurs with small instruments and even with no instruments at 

 all. 



The advantages of the reflecting and refracting forms of telescope 

 were briefly summarised, a few remarks made on the fitting up of 

 small observatories, and advice was given as to the magnifying 

 powers to be used for different kinds of work. Various accessories 

 to the telescope were shown and their use explained, such as (1) the 

 Barlow lens, (2) the star diagonal, (3) the sun diagonal, (4) the 

 Zollner spectroscope. The lecturer showed on the screen a number 

 of photographs and diagrams, most of which were his own work. 

 Three excellent diagrams illustrated the ''scale of the degree," the 

 " scale of the minute," and " the scale of the second " respectively. 

 Some interesting and valuable suggestions were made as to the 

 various classes of astronomical work open to the amateur, and at the 

 conclusion of the lecture Mr. Barlow exhibited some fine drawings 

 of Halley's Comet, the Daylight Comet of 1910 and the phenomena 

 of Jupiter's satellites. 



P On March 18th, Percival J. Parmiter, Esq., 



tl l0 ~ h lectured on " The Principles of Radio-telegraphy." 



A number of lantern-slides were shown on the 

 screen and one or two interesting experiments were performed. A 

 brief description was given of the various types of high-tension 

 sparks which can be produced and the construction and method of 

 employment of the Marconi coil were thoroughly explained. 

 Various forms of spark-gap apparatus were passed under review, 

 full details being given in the case of some of the more important. 

 The lecturer also gave the history of the <; Coherer," and of certain 

 other appliances used either in the reception or transmission of 

 signals and succeeded in giving as full and clear an account of an 

 interesting but somewhat difficult subject as was possible within 

 the limits of a single lecture. 



