METEOROLOGY. * 521 



(5.) From .all this it results, however, that we have little or no pros- 

 pect of attaining to au exact psychrometer formula, and therefore need 

 not expect to obtain the vapor tension accurate to 0.1 uuu by meaus of 

 the psychrometer. (Pernter, Psychrometer titudien.) 



Wild, in some remarks upon the establishment of anemometers, op- 

 poses the statement of Dr. Schreiber that the self-recording Robinson 

 anemometer is better adapted than Wild's tablet anemometer by the 

 statement of his own convictions that the latter is not only much more 

 convenient but also more accurate ; in this last particular his anemo- 

 meter seems to have exceeded Wild's expectations, his original idea 

 having been merely to devise an instrument that should be more con- 

 venient and simple, and therefore adapted for the use of numerous 

 stations. In simplicity and cheapness the tablet anemometer apparently 

 cannot be excelled. Wild's experience in northern regions shows that 

 the self-recording Kobiuson anemometer cannot be kept in continuous 

 operation owing to the cold, the snow, and frost-work, and that it is only 

 practicable to use it at second-class stations when the observers are 

 thoroughly drilled as at the Army Signal Office. With regard to the 

 Hagemann aspiration-anemometer, especially as made by Nyrop, in 

 Copenhagen, he finds that it is simple, easy to use, convenient, and 

 accurate to read, even at night time, since the dial can be placed within 

 the building while the conical point is established above the roof; the 

 price of this apparatus is twice that of the tablet anemometer, and this 

 alone is an objection to its general introduction. (Z. 0. (x. j¥.,xvii, p. 211.) 



H. Louis F. Melsens presented to the Congress of Electricians a 

 memoir on the lightning conductor and its history since the days of # 

 Benjamin Franklin. The two principal forms of protection against light- 

 ning are, first, that of Gay Lussac, who advocates a small number of 

 conductors having large sections and raised to great altitudes; and, 

 second, the system of Melsens, who advocates the employment of nu- 

 merous conductors having small sections and numerous points not 

 greatly elevated, the whole forming a sort of wire cage. He elaborates 

 in full the scientific reasons that have led to these two forms of the 

 original lightning conductor of Benjamin Franklin. (Z. 0. G. M., xvit, 

 p. 49.) 



Dr. K. Weirauch contributes formulae and methods for the convenient* 

 application of Bessel's sine and cosine formula to meteorological obser- 

 vations in hopes that from numerous such applications one may derive 

 values of the constants for many localities by the study of which latter 

 further progress may be made in climatology. He gives four methods 

 for the determination of these constants from equidistant phases, namely, 

 interpolation by differences (two methods), parabolic interpolations, 

 goniometric interpolations. The differences between the results of these 

 four methods are slight but important; the last two are rigorous and 

 preferable. (Z. 0. G. M., xvm, p. 20.) 



