July 13, 1883.] 



SCIENCE. 



61 



behind this flannel curtain, through wliicU .sufficient 

 light from the three lamps conies to enable the 

 change to be made without further artificial Jigbt. 

 The orange flannel serves to satisfactorily exclude 

 actinic light. 



The traces, removed from the cylinders, are then 

 carried in a large envelope to the dark room, and 

 there developed, the developer used being pyrogallic 

 acid. Tlie best developments are those which take 

 place rather quickly, in about ten to fifteen minutes. 

 When the development is slower, the traces are 

 usually found inferior. After the development is 

 complete, the traces are fixed in hyposulphite of 

 soda cleansed in a saturated solution of alum, washed 

 for about two hours in running water, and then liung 

 up to dry. After drying, the date is stamped upon 

 them. The exact instant of beginning and ending of 

 each line on the trace, together with the correspond- 

 ing scale value, is written on. Time observations, 

 with sextant and artificial horizon, are taken from 

 time to time, usually monthly, to regulate the stand- 

 ard chronometer. 



After the traces have been thus completed, they 

 are practically paper negatives, from which any num- 

 ber of copies may be made photographically. Two 

 sets are made by the well-known blue-print process. 

 The traces require no special treatment, such as oil- 

 ing, waxing, etc., for the successful application of 

 this process. 



For tabulating from tlie traces, it is found most 

 convenient to use a ruler subdivided into hourly 

 divisions for the time scale, and a triangular piece of 

 card-board upon the edge of which is ruled the scale 

 corresponding to the trace to be read. The unifilar 

 and bifilar traces have all been read, tabulated, and 

 tlie means calculated. The vertical-force traces have 

 not yet been read. 



There is also in the magnet-room of the observa- 

 tory a thermograph, which records the temperature 

 every half-hour. From the records produced by it, 

 the time of maximum temperature in the observatory 

 is found to be about five p.m., and the time of mini- 

 mum temperature, about half-past eight a.m. At 

 these hours the thermometers under the bell glasses 

 and near the magnets are read; and from these read- 

 ings it appears that the magnets are subjected to 

 an average daily range of temperature of about 

 13° C. 



On the 14th, 15th, and 16th of each month, obser- 

 vations are made to determine the absolute decli- 

 nation, dip, and intensity. These observations are 

 made in the usual manner of taking such obser- 

 vations by field parties in the coast .ind geodetic 

 survey. Monthly reports and returns of results are 

 made to the superintendent of the survey. 



The declinations and dips have all been computed, 

 but the intensities only approximately as yet. The 

 following table contains the declinations and dips 

 resulting from the monthly absolute determinations. 

 Each declination is the mean derived from the elon- 

 gation on three successive days, and each dip Is the 

 mean of six sets with two needles on the same three 

 days. 



U. 8. magnetic observatory at Los Angeles, 

 tat. S4°0S', long. 118°15' W. G. 



IH82, Sept. 14, IS, le 



Oct. 14, 15, 16 . 



Nov 



Dec-. 



18S3, Jan. 



Feb. 



14, 15 



14, 15, 18 . 



14, 15, 16 . 



14, 15, 16 , 



March 14, 1ft, 16 . 



.Vpril 14, 16, 16 , 



May 14, 15, 16 . 



The horizontal intensity is approximately 5.97 

 British units = 0.275 dyne. 



U. S. magiiL'tic obst-rvatcry, 

 I,o» Angek-9, Cal., June 1, 18S3. 



NOTES AND NEWS. 



Professor Huxley has been elected president of the 

 Royal socitty of London, in the place of Mr. Spottis- 

 wood. 



— The recently issued report of the signal-office 

 for 1881 contains a record of primary and secondary 

 observing stations, established in that year in Alaska, 

 with summaries of observations at some Alaskan 

 stations in preceding years. There is also some 

 account of the fitting-out of the Greely expedition 

 to Lady Franklin Bay and that to Point Barrow. 

 But the most important article for arctic students is 

 the report of Prof. E. W. Nelson on the meteorology 

 of St. Michaels, Norton Sound, where, as is well 

 known, he Iiad been stationed for four years; his 

 leisure being employed in pursuing investigations 

 into the natural history and ethnology of the region 

 with the greatest energy, devotion, and success. 

 The article itself being a summary and an abstract, 

 with somewhat wider limits in regard to the treat- 

 ment of auroras and the so-called ' polar band ' 

 formation of clouds, it will not be attempted to con- 

 dense it here, but merely to call attention to some 

 of its leading features. According to observations 

 by Danenhower, the position (hitherto somewhat 

 uncertain) of St. Michaels is latitude 03° 28 j', and 

 longitude 162° 04J' west. The mean annual temper- 

 ature for the period Is 25° .5 F. The highest observed 

 temperature was 75°, and the lowest, — 55°. A 

 curious fact was noted with great regularity. In 

 early winter darkness comes on between three and 

 four P.M., and the temperature falls until about six 

 P.M., when a rise follows of two or three hours' dura- 

 tion, and sometimes five or six degrees in extent, fol- 

 lowed by the usual steady nocturnal fall. It does 

 not result from cliinges in the wind, but may be due 

 to greater radiation immediately after sunset from 

 the land, resulting in local atmospheric movements, 

 causing warmer air from the adjacent sea to flow in 

 the vicinity of the station. 



Alongshore, winds N.,\.E.,S.,S.E.,S.W., are most 

 prevalent. Winds off the sea, N.W. and W., are the 

 least frequent, not exceeding together over ten per 

 cent of the whole. Topographical bias is, however, 

 distinctly evident, as at most stations in Alaska. 



