'New Zealand Institute Science Congress. 483 



" The North-west Winds of Canterbury," by Mr. H. F. Skey. (Printed 

 in the N.Z. Journal of Science and Technology, vol. 2, pp. 300-1, 1919.) 



" The Harmonic Analysis of Tidal Observations and the Prediction of 

 Tides," by Dr. C. E. Adams. 



ABSTRACT. 



Practically all existing metliods used for the harmonic analysis of tidal 

 observations have many numerical approximations employed in their prac- 

 tical applications. It therefore becomes difficult to determine whether the 

 method of harmonic analysis gives the best representation of the tide 

 curve. 



In the method here described no arithmetical approximations are used, 

 so that a criterion is obtained to test the application of Fourier's series to 

 tidal observations. 



A description is given of the method of prediction of tides used in New- 

 Zealand. An illustrated description of this process appeared in the Survey 

 Reports of the Lands and Survey Department for the years 1910-14, and 

 to these reports reference should be made for the details. The process is 

 a graphic one, controlled by calculation. The results of the predictions 

 for Wellington and Auckland are published in the Netv Zealand Nautical 

 Almanac by the Marine Department. 



" A Slide-rule for solving the Quadratic Equation."" by Professor D. M. Y. 

 Sommerville. 



" Porosity of Porcelain Insulators," by Dr. C. C. Farr. (Printed in the 

 N.Z. Journal of Science and Technology, vol. 2, pp. 302-7, 1919.) 



" Interference of Power Circuits with Telephone Circuits,'" by Mr. E. 

 Parry. (Printed in the N.Z. Journal of Science and Technology, vol. 2, 

 pp. 308-14, 1919.) 



" The Effect of Low Power-factor from the Standpoint of Electric-power- 

 station Operators," by Mr. E. E. Stark. (Printed in the N.Z. Journal of 

 Science and Technology, vol. 2, pp. 314^17, 1919.) , 



Friday, 7th February, 1919, 10 a.m. 



Present : Professor T. H. Easterfield, President, in the chair, and a 

 number of others. 



Papers. — " National Hvdro-electric Schemes for New Zealand," bv Mr. 

 H. Hill. 



■■ Exhibit of Photographs on Glass of Solai' Corona, taken by Lick 

 Observatory. 8th June, 1918, at Goldendale, Washington, U.S.A.," by Dr. 

 C. E. Adams. (Printed in the N .Z. Journal of Science and Technology. 

 vol. 2, pp. 317-19, 1919.) 



" Deteimination of the Position of the Moon b\- Photography, and 

 Exhibit of Photographs of the Moon and Surrounding Stars," b\^ Dr. C. E. 

 Adams. 



abstract. 



An exhibit was made of ])liotogTaphs, taken at the Lick Observatory, 

 of the moon and surrounding stars, to determine with great accuracy the 

 position of the moon. This work was undertaken to enable Professor 

 E. W. Brown, the eminent mathematical astronomer at Yale, to check his 

 new tables of the moon. On the original |)lates stars as fnint as the tenth 



16* 



