206 H. Gruener — Standard Solutions of Tartar Emetic. 



From the data given above it appears probable that the 

 larger part of contents of the veins should be regarded as 

 country rock intensely altered by solutions containing heavy 

 metals and boron, ascending along narrow cracks and fissures. 



Somewhat similar deposits have recently been described by 

 W. Moericke from Chile. * In these occurrences a hornblende- 

 biotite-granite of probably Tertiary age is in the vicinity of 

 the veins altered to a tourmaline rock nearly identical with 

 that here described; the veins proper occur in this tourmaline 

 rock and consist of quartz with but little tourmaline, together 

 with auriferous copper ores. 



Washington, D. C, April, 1893. 



Art. XXXI. — The Stability of Standard Solutions of Tartar 

 Emetic; by Hippolyte Grcjener. 



[Contributions from the Kent Chemical Laboratory of Yale College — XX VI.] 



During the progress of some investigations on antimony, I 

 found it desirable to know to what extent a solution of tartar 

 emetic could be relied on to retain its strength when kept for 

 a length of time. Accordingly I made up a number of solu- 

 tions of tartar emetic, whose strength was determined by titra- 

 tion in presence of an alkaline tartrate and bicarbonate with 

 decinormal iodine, standardized against arsenious oxide. These 

 solutions were put aside in stoppered bottles for a number of 

 months, when they were again determined with iodine stan- 

 dardized against the same arsenious oxide. 



Solution A was simply tartar emetic in distilled water, 16 

 grms. to the liter. At the end of five months this w T as found 

 to have lost strength to a considerable extent, while a deposit, 

 seemingly a mixture of antimonious oxide and of fungus 

 growth had settled at the bottom of the bottle. At the end 

 of fourteen months a still greater loss of strength was ob- 

 served, corresponding in all to about 3 5 per cent of the tartar 

 emetic, of which 4 grms. were present. The sediment was 

 drained, dissolved in tartaric acid and titrated with iodine. It 

 was found to correspond to *13 grm. of tartar emetic or 

 approximately the amount lost. This shows clearly that under 

 the conditions no great loss is caused by the formation of the 

 pentoxide, in closed bottles at least. 



Solution B was slightly alkaline with sodium bicarbonate in 

 presence of sodium tartrate. On this solution after five 

 months there was developed in addition to a fungus growth a 



* Min. und Petr. Mitth., xii. No. 3. 



