232 



Royal Society. 



there is some connexion between their power to saturate the affi- 

 nities of other elements, and their power to retard the rays oflight. 



Element. 



Atomic 

 weight. 



K ef r a cti on -equi va! en t. 



Specific refractive 

 energy. 



Aluminium 

 Antimony . 



Arsenic 



Barium 



Boron 



Bromine.... 

 Cadmium . 

 Caesium .... 

 Calcium .... 

 Cai-bon .... 

 Cerium .... 

 Chlorine.... 

 Chromium . 

 Cobalt .... 

 Copper .... 

 Didymium. 

 Fluorine.... 



Gold 



Hydrogen . 



Iodine 



Iron 



Lead 



Lithium 



Magnesium 

 Manganese. 

 Mercury.... 



Nickel 



Nitrogen.... 

 Oxygen .... 

 Palladium . 

 Phosphorus 

 Platinum . 

 Potassium . 

 Ehodium . 

 Rubidium . 



Silicon 



Silver 



Sodium .... 

 Strontium . 



Sulphur 



Thallium . 



Tin 



Titanium . 

 Vanadium . 



Zinc 



Zirconium . 



27'4 

 122 



75 

 137 



11 



80 

 112 

 133 



40 



12 



92 



35-5 



52-2 



58-8 



634 



96 



19 



197 



1 



127 



56 



207 



7 



24 



55 

 200 



58-8 



14 



16 

 106-5 



31 

 197 4 



39T 

 1044 



85-4 



28 

 108 



23 



87-5 



32 

 204 

 118 



50 



5P2 



65-2 



89-6 



8-4 

 24-5 

 15-4 

 15-8 



40 

 15-3 

 136 

 13-7 

 10-4 



50 

 13-6 



99 

 159 

 10-8 

 11-6 

 12-8 



P4 

 24-0 



1-3 

 24-5 

 12-0 

 24-8 



3-8 



70 

 12-2 

 20-2 

 10-4 



4-1 



2-9 

 22-4 

 18-3 

 260 



8-1 

 24-2 

 140 



(other values ?) 

 In dissolved salts 16 - 9 



In dissolved salts 1C*7 

 In chromates 23 ? 



In hydracids 3-5 



In dissolved salts 27 '2 

 In ferric salts 20' 1 



In permanganate 26 2 ? 



In high oxides 53 



(other values ?) 



? In silicates G'8 



CO 



157 

 4-8 

 13-6 



16-0 (other values?) 

 21-6? 

 19-2? 

 25-5? 

 25-3 ? 

 10-2 

 210? 



0307 



0-201 ? 



205 



0115 



0-364 



0191 or 0-211 



0121 



0103? 



0-200 



0-417 



0148? 



0-279 or 0-301 



0-305 or 0-441 ? 



0184 



0-183 



0133? 



0073 ? 



0-122 ? 



1-3 or 3-5 



0193 or 0-214 



0-214 or 0-359 



0120 



0-543 



0-292 



0-222 or 0-476? 



0-101 ? 



0-177 



0-293 or 0-379 



0-181 



210 ? 



0-590 



0-132 



0-207 



0-232? 



0164 



268 ? or 0-243 



0-145? 



0-209 



0155 



0-500 



0106? 



01 63 ? 



0510 ? 



0-494 ? 



0156 



0-234 ? 



