722 SEC. 14. METEOROLOGY. 



The case contains a psychrometer and a thermograph (minimum and maxi- 

 mum thermometer) ; it is kept at a proper distance from the window, and 

 when in this situation the sliding door is closed ; on bringing it nearer to the 

 window, for the purpose of reading off the indications, the door opens auto- 

 matically. 



2932. Collection of Weather Maps of the German Naval 

 Observatory, for the month of March 1876. 



Imperial Admiralty Hydrographical Office, Berlin, and 

 German Naval Observatory, Hamburg. 



2933. Storm Warner and Weather Indicator, original 

 instrument, 0*85 in. long and 0*50 in. broad. 



Annexed to the same is a treatise entitled : " Der Sturmwarner 

 " und Wetleranzeiger, ein nach wissenschaftlichen Grundsatzen 

 " ausgefiihrtes und durch Beobachtung und Erfahrung bewahrtes 

 " Instrument zur VorherbestimmuDg von Sturm und Wetter." 



Prof. Prestel, Emden. 



2934. Graphical Representation of the changes of the 

 weather in the years 1857, 1858, and 1859. 



Prof. Prestel, Emden. 



2935. Diagram of Solar Spots and their connexion with 

 the variations of magnetic declination. 



Prof. Rod. Wolf, Zurich. 



The upper black curve gives the monthly relative numbers, introduced by 

 him, for the years 1831-1875 ; the red one their means from twelves to 

 twelves. The lower black curve gives the corresponding yearly relative 

 numbers for the years 1745-1875 ; the red curve their reduction to the scale 

 of the variation of magnetic declination at Prague. To the last curve are 

 added (in black colour) those obtained from observation of the variation of 

 magnetic declination at Mannheim, Paris, London, Gottingen, and Prague, 

 demonstrating the connexion between the frequency of the solar spots and 

 the variation of magnetic declination. 



2937. Shortrede's Barometric Slide Uule, as arranged by 

 Major-General A. De Lisle, R.E., for barometric readings and 

 boiling points. Elliott Brothers. 



The barometric scale is calculated from Bailey's formula. The range ex- 

 tends to about 15,000 feet of altitude, occupying the three faces of the slides. 

 The back has logarithmic lines for computing the corrections, scales of which 

 are given on the edges. The method of using the lines is given on the face 

 of the rule. The corrections are : 1st, for temperature of mercury ; 2nd, for 

 temperature of air ; and, 3rd, for latitude. Aneroids only require the two last. 

 This rule was invented by the late Major- General Shortrede, formerly of the 

 Great Trigonometrical Survey in India. 



The logarithmic slide solves the following equations : 



, a ab c 



x=ab; #= ; x= ; x= - 



o c ab 



