56 



NATURE 



[November io, 1910 



pressions or the fronts of well-developed Antarctics, a 

 typical rainfall curve of the northern areas was con- 

 structed. Thus for each half-year the low- and high- 

 pressure systems passing Victoria were counted, and along- 

 side the numbers thus obtained were placed the figures 

 for the rainfall over the northern areas and the mean 

 air pressure and temperature for Melbourne. The com- 

 parison brought out the result that an excess in the 

 number of summer monsoonal disturbances was followed 

 by an excess in the winter rainfall in seventeen cases out 

 of twenty-two. 



Mr. Quayle then evolves a rough rule for predicting the 

 approximate winter rainfall over northern Victoria, giving 

 the weights of two, one and one to the number of mon- 

 soonal disturbances, mean pressure, and mean tempera- 

 ture, respectively, for the preceding summer. Noting the 

 coincidences of sign only in the values he evolves for the 

 calculated winter rain, he finds that they are in agree- 

 ment with those for the actual departures from normal 

 of the winter rains nineteen times out of twenty-two, and 

 in serious agreement in two cases only. It is unfortunate 

 that, owing to lack of daily isobaric charts, the period 

 could not have been extended over more years ; neverthe- 

 less, the system may be used tentatively, and the results 

 will be watched with interest. 



THE LATITUDE OF ATHENS.' 

 TN the volume referred to below M. Eginitis describes 

 -^ the varied activities that exercise the staff of the 

 National Observatory of Athens and of the smaller institu- 

 tions that his zeal has called into existence and made to 

 yield results useful to science, both as regards seismology 

 and meteorology. It seems not a little strange to find 

 well-remembered names like Thebes, Sparta, Naxas, 

 Samos, and many others famous in the past, figuring in 

 this list, and playing a new role by contributing climatic 

 observations made on approved lines with modern instru- 

 ments. Of the last mentioned of these stations, that on 

 the island of Samos, the author remarks, " malheureuse- 

 ment, elle a ^t6 compl^tement d^truite, le jour du bom- 

 bardement de cette ile, en 1908, par la flotte turque," 

 recalling a struggle which seems more in keeping with 

 its ancient history than its effort to accumulate meteor- 

 ological observations. 



But the real serious piece of work here described is 

 the attempt to determine the latitude of Athens, a problem 

 that interested Ptolemy, who recorded the value 37° 15', 

 placing the city some 45 kilometres south of its true 

 «ite, even when allowance for all known sources of error 

 is made, a larger error than is usual in similar deter- 

 minations in that age. But error seems to cling to this 

 unfortunate coordinate, for M. Eginitis informs us that 

 the latitude for the Pantheon given in the " Connaissance 

 "des Temps " is about 6" too small. In striving for the 

 nicest accuracy, the director has found the problem to be 

 one of extreme difficulty. He has employed two methods 

 and two instruments, and the results do not coincide. 

 He has employed the Horrebow-Talcott process, carried 

 out by means of an instrument originally intended for a 

 meridian circle, but by removing the microscopes and 

 adding a level, adapted to that particular form of observa- 

 tion. Later, through the generosity of M. Syngros, he 

 was supplied with a modern and excellent meridian circle 

 "by Gautier, the construction of which was supervised by, 

 M. Loewy. This instrument was used for determining 

 the zenith distances of both circumpolar stars and stars 

 of known declination, the zero being derived from nadir 

 observations only. 



The interest in the discussion consists in the different 

 values obtained after reversing the instrument. The 

 <iifferehce is constant and rather larger than has been 

 noted elsewhere. Like the R-D term in similar inquiries, 

 It refuses to yield a satisfactory explanation, however 

 ingeniously solicited. There is no attempt to determine 

 the actual variation of latitude, though the observations 

 extend over a considerable period, nor, as we think, is 



1 Anna'es de I'Observatoire National d'Athenes, oublirf par Demi'rius 

 Eginitis, Directeur de I'Observatoire. Tome v. Pp. ii + 592. (Athens, 

 1910.) 



sufficient attention paid to the possible effect of a " magni- 

 tude equation." The inquiry is of a purely instrumental 

 character, and is directed mainly to the legitimacy of 

 employing an arithmetic mean of the values obtained in 

 the two positions of the instrument, if this conclusion 

 is warranted and offers the only possible means of correctly 

 determining the latitude, M. Eginitis is justified in insist- 

 ing upon the necessity of reversion and of providing for 

 the operation in the construction of the instrument. But 

 as the director promises further experiments and a more 

 rigorous attempt to eliminate all possible sources of error, 

 it will be desirable to pause before offering any criticism 

 or accepting the result as final. 



EDUCATION IN TECHNICAL OPTICS. 



T^HE reawakening of the British optical industry whicli 

 ■*■ began with the first years of this century brough: 

 with it a demand for the provision of special technical 

 education in optics. The Northampton Polytechnii 

 Institute, from its situation in Clerkenwell, where much oi 

 the London optical industry is centred, was particularl\ 

 suited as a centre for such work, and optical classes wer^ 

 begun there as a branch of work in general physics. Th> 

 optical trade, however, regarded these classes as being oi 

 little value, and in 1902 a new syllabus was adopted and ' 

 special department of technical optics was instituted 

 Since that time this department, under Mr. S. D 

 Chalmers, has developed very considerably and done muc! 

 useful work for both day and evening students, but th- 

 scope and value of this work has been continually hampered 

 and further development has been completely blocked b\ 

 want of proper space and equipment. This unsatisfactorv 

 state of affairs has been fully realised, and the governor- 

 of the Northampton Institute have acquired the necessarx 

 land on a site opposite the institute, and have had ^plan- 

 prepared for a complete " Opto-technical Institute"; fo 

 the erection and equipment of the building they are, how 

 ever, dependent on a grant from the London Count \ 

 Council. . 



The County Council or its predecessors in authontv, 

 the School Board, has been repeatedly approached in thi- 

 matter. A deputation from the Optical Society in 1902 

 led to a grant which resulted in the establishment of tli 

 optics department at the institute; for a time this w.i 

 supplemented by a grant from the Company of Spectacl- 

 Makers, but this has subsequently been replaced by a trad- 

 fund, collected principally by the efforts of Mr. J. Aitchison 

 and administered by the Optical Society. In 1905 th 

 Optical Convention sent a deputation to the London Educ..- 

 tion Committee ; this deputation was headed by Dr. R. I 

 Glazebrook, and included a large number of influential 

 men connected with the science or industry of optics, but. 

 although favourably received, no practical steps result, 

 for five years. . 



Now, 'however, there appears to be a definite prosper 

 that this want of our optical industry may soon be met 1; 

 an adequate manner. This is indicated by a circular lett. 

 issued a few weeks ago by the L.C.C. Education Oflic 

 to members of the optical trade in London. In this lett. 

 the members of the trade are asked to state their viev 

 as to the need for an Opto-technical Institute in Londo; 

 and to indicate to what extent they or their employ, 

 would take advantage of anv facilities provided, and wh;. 

 benefits they would expect to derive from such teachin.. 

 The letter concluded by inquiring whether, in the opinij 

 of the trade, an expenditure of about 30.000/. for a buil. 

 ing for such a purpose would be justified, and the genei ; 

 scheme of the new institute as proposed by the Northami 

 ton Institute is indicated. This comprises a series of lar;. 

 teaching laboratories and lecture-rooms for instruction 1 

 all branches of optics, lens-working and general instruirier 

 design and construction being provided for. as well as t. 

 theoretical and extierimental branches of the subject. 1 r 

 new institute would accommodate 300 to 400 day and evf-r 

 ing students, complete day courses as well as evenin.i, 

 classes being contemplated. 



Fortunately there is every reason to believe that the 

 optical trade' will respond to this circular letter in a manner 

 which will fully justify the London County Council in 

 proceeding at cnce with a scheme which is really of 



NO. 2 141, VOL. 85] 



