CONTENTS. 



IX 



134. Vapor pressures of solutions of salts in water .... 



135. Pressure of aqueous vapor at low temperatures .... 



136. " " " " 0° to 100° C (Broch) .... 



137. " " " " 100° to 230° C (Regnault) . 



138. Weight in grains of aqueous vapor in a cubic foot of saturated air 



139. •* " grammes of " " " " " metre of 



140. Hygrometry, vapor pressure in the atmosphere . 



141. " dew-points ....... 



142. Relative humidity ........ 



143. Values of o.378<? in the atmospheric pressure equation h^B — 0.378^ 



144. Table for facilitating the calculation of hfido 



145. Logarithms of ///760 for values of h between 80 and 800 



146. Values of i -(-0.00367 t : 



id) for values of t between 0° and 10° C, by tenths . 

 \b) " " " " " —90° " -f-i99o° C, by tens 

 ic) logarithms for t " — 49° " -[-399° C, by units 

 {d) " " " " 400° •' 1990° C, by tens . 



147. Determination of heights by the barometer .... 



148. Barometric pressures corresponding to different temperatures of the 



boiling-point of water : 



(a) Common measure ...... 



(Ji) Metric measure ....... 



149. Standard wave-lengths : Fabry-Buisson's iron arc lines 



150. " " " red cadmium line .... 



151. Stronger lines of some of the elements .... 



152. Rowland's standard solar wave-lengths (also corrections) 



153. Kayser's standard iron arc lines (also corrections) 



154. Wave-lengths of the Fraunhofer lines ..... 



155. Photometric standards ........ 



156. Sensitiveness of the eye to radiation of different wave-lengths: low 



(threshold) intensities 



157. Sensitiveness of the eye : greater intensities .... 



158. Sensibility of the eye to small differences of intensity (Fechner) 



159. Solar energy and its absorption by the earth's atmosphere . 



160. The solar "constant" of radiation and temperature of sun . 

 r6i. Distribution of intensity of radiation over solar disk 



162. Relative intensities of sunlight and sky-light 



163. Indices of refraction of Jena glasses 



104. ..... 



165. " ** " " " " temperature coefficients 



166. " ** " " various alums . . . . . 



167. ** " " " metals and metallic oxides : 



{a) Kundt's experiments ...... 



(J>) Du Bois and Rubens' experiments 



(r) Drude's experiments ...... 



168. Indices of refraction for rock salt 



169. " " " " " " temperature coefficients . 



170. " " " " sylvine 



149 



151 

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162 



163 

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168 

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174 

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