OF ARTS AND SCIENCES. 107 



The want of closer agreement in the results, both with each other 

 and with theory, we traced to a slight admixture of Sb^O^Clj ; and 

 we found that this last compound was by far the more readily 

 formed of the two, and, except in the single experiment by which the 

 preparation subsequently analyzed was obtained, the chief product of 

 the reaction was largely mixed with the more oxygenated compound, 

 even when the prescribed formula had been closely followed. 



By operating with several hundred grammes of antimonious chloride 

 and alcohol, we obtained the compound Sb^O.Clj in beautiful large 

 crystals, some of which were over a centimetre in length. We 

 used for the purpose a cylindrical vessel of platinum, having a capa- 

 city of about 300 cubic centimetres ; which, when covered with a lid of 

 the same material, fitted exactly the interior of a Papin's digester, made 

 nearly after the pattern recommended by Frankland* This device 

 was suggested by the "soda-water" fountains described on page 118 of 

 the previous volume of these " Proceedings." . The outside shell of 

 such fountains must necessarily be very strong, and is now often made 

 of steel plates ; but the aerated water is held by an interior vessel, 

 which, though independent of the shell, forms its lining. This inner 

 vessel may be even of glass, for it bears no strain ; since a small aper- 

 ture through the neck equalizes the pressure on the outer and inner 

 surfaces, and the " lining " fits the shell so tightly that no space is left 

 into which the contents can overflow. 



The general form of the crystals of Sb^O^Clj, prepared as we have 

 described, is shown by Fig. 8, Plate I., and they are evidently more 

 highly modified than those figured by Schaeffer. They are frequently 

 terminated at the two ends, and usually differently terminated, as our 

 drawing represents. At one end, we have an acute tetrahedral solid 

 angle, formed by the meeting of the planes of a hemioctahedi-on with 

 those of a vertical dome, while at the other end we have an edge 

 formed by the meeting of the single basal plane with the single plane 

 of an orthodome found on the crystal. These crystals thus present a 

 very striking example of hemihedrism at the terminations, and we 

 propose to examine hereafter their polar relations. The faces have a 

 high vitreous lustre, and many of the angles can be measured with 

 great precision. Unfortunately, however, but as a natural result of 

 the multiplication of the octahedral planes, the faces of the principal 

 prism are generally striated parallel to the basal intersections, and this 

 striation renders more or less uncertain the measurements of the angles 



* Watt's Dictionary of Chemistry, article Bath, i. 520. 



