CHEMISTRY. 



Ill 



IH by no meani been confirmed. On the oon- 



in- k 'ood* may be used for any deaiml artiolo 



tro. I nave also uimlu another observa- 

 <mt aniline Muck with whito goods, print. -.1 mi 

 : _' thin prepared, was much less daveloptd n 

 I.-I-M.I.' of the texture, than when printud 

 with mi]>iv[iurud undurlayers, while at the sanu- time. 

 : u'k was fully developed on the upper tide. 

 Aniline block, even when prepared from the 

 L>triii'tioiis, must affect the strength of tiie 

 thr.M I, ami all the more HO in proportion an it can 

 >n it on all sides ; but here the damp under- 

 side of the print comes into close contact with the 

 illuminate of soda of the underluyor, and takes up 

 a portion of the latter, by which this side of the 

 i is guarded against any perilous exposure to 



al reaction. At the same time, also, a guar- 

 antee is obtained for the relative strength of the 

 whole texture. 



Alizarin at a Tett. Prof. A. R. Leeds gives, 

 in tho American Chemist, an account of his 

 fX|>vriments on the value of alizarin as a re- 

 agent. By digesting for a short time with 

 alcohol of 95 per cent., a solution was obtained 

 holding in one cubic centimetre 0.00425 gramme 

 alizarin. One cubic centimetre of this solu- 

 tion imparted a bright-yellow color to a litre 

 of water. By the addition of 2.25 cubic 

 centimetres of a solution containing 0:000198 

 gramme potash per cubic centimetre, the yel- 

 low changed to a distinct rose-color, indicat- 

 ing the presence of one part of potash in 

 more than 2,000,000 parts of water. A simi- 

 lar change of tint was produced by 0.00032 

 gramme soda dissolved in a litre of water, or 

 one part in more'than 3,000,000. The addition 

 of 6 milligrammes of potash and 4 milligrammes 

 of soda, to a litre of water containing 0.00425 

 gramme alizarin, changed the yellow into a 

 rose-color so dark that any further deepening 

 of the color was too inappreciable to be used 

 as a means of detecting an increase in the per- 

 centage of alkali. On instituting a compari- 

 son between litmus and alizarin, it was found 

 that a litre of water containing 0.0066 gramme 

 of the latter with 0.0008 gramme of the acid 

 H,SO 4 underwent the same change of color 

 as a litre of water containing 0.02 gramme 

 litmus and 0.0024 gramme H Z SO 4 . 



A number of samples of drinking-waters gave a 

 strongly alkaline reaction with alizarin, those of 

 Hoboken and New York changing the color to a 

 dark red. A litre of Croton water, drawn from a 

 hydrant in the lower part of New York, January 

 2d, gave a bright cherry-color with 0.0066 gramme 

 alizarin, and acquired the same tint as that imparted 

 by 0.0016 gramme soda to a litre of distilled water 

 containing 0.0066 gramme alizarin. The yellow 

 color was restored to the latter by 0.004 gramme 

 HaS0 4 , to the former by 0.03 gramme II a S<J 4 . In 

 this way the alkalinity of a number of samples of 

 drinking-water may be rapidly compared, and the 

 total amount of acid required to neutralize the ba?es 

 may be determined without previous condensation. 



In all the above cases extremely dilute solutions 

 were, employed, and no change of tint and uo pre- 

 cipitation or the coloring-matter was observed even 

 Banding a number of hours. But, when larger 

 amounts of coloring-matter and an excess of acid 

 were present, the alizarin was partly precipitated and 

 rendered the liquid turbid. 



Tht! distilled water in common use at the Stevens 

 Institute', condensed in a worm of block-tin and 



collected in stone-ware jum, was invariably alkaline : 

 collected in I..,-. tlr* of white glus, it hod a neutral 

 ii. Sn ow-water measuring 60 c.c., obtained 

 by melting the nowwttoti fell on December 27th, 

 or last year, and titrated tit the temperatur. 

 room, wait neutral. Some precaution* are necessary 

 for the preparation of tet-puj>er with this P-ngcnt. 

 Thin uiiMZ.-d whito paper, which had been custom- 

 arily employed in tim preparation of litniUM-paper, 

 was turned red by the alizarin solution, mid it wa* 

 necessary to have recourse to tine Swedish fil' 

 paper. The commoner Swedish paper turned tho 

 yellow to a brownish-yellow color. Kven the best 

 French gelatin could not be employed to size the 

 paper used for testing, since it maniieated a slightly 

 alkaline reaction. Alizarin test-paper, as above pre- 

 pared, when moistened with a drop of saliva, is 

 strongly reddened, and should be employed by 

 physicians in place of litmus. I have likewise em- 

 ployed white silk and nilk thread dyed with alizarin, 

 ana this mode of applying the test may in somo 

 cases be found useful. 



New Method of assaying Lend- Ores. Ac- 

 cording to the method proposed by A. Mas- 

 cazzini, the ore or other substance is oxidized, 

 and its metals converted into sulphates before 

 reduction. The best agent for this purpose is 

 sulphate of ammonia. The ore is mixed with 

 an equal or double weight of the sulphate, ac- 

 cording as it supposed to be poorer or richer, 

 and the mixture is ignited in a small porcelain 

 crucible, covered to prevent spirting. When 

 cold, the mass is treated with boiling water, 

 acidulated with sulphuric and muriatic acid ; 

 thus the sulphates and oxides of iron, copper, 

 etc., are dissolved, the lead and silver remain- 

 ing insoluble. 



This portion is washed by decantation, tho 

 washings being passed through a filter. This 

 filter is next dried and its ashes added to the 

 dried insoluble portion. It is then mixed with 

 muriatic acid and powdered zinc, in order to 

 reduce the sulphate of lead and the chloride of 

 silver. The metallic deposit is washed with 

 water which has been boiled, or acidulated 

 with sulphuric acid, and is then pressed into a 

 compact mass. 



This is dried and heated with from 1 to 2 

 parts its own weight of a flux composed of 13 

 grammes of carbonate of potassa, 10 grammes 

 carbonate of soda, 5 grammes of melted borax, 

 and 5 grammes of farina. The whole is covered 

 over with dried chloride of sodium, and the 

 heat is raised by degrees to redness. When the 

 whole is in a state of quiet fusion, it is submit- 

 ted for a moment to a higher temperature. 

 This process serves for determining lead and 

 silver in white-lead, red-lead, ores rich in gold 

 and silver, also antimony, tin, and copper. If, 

 in the assay of ores of gold and silver, the 

 amount of lead is insufficient, pure oxide of 

 lead is added. 



Extraction of Vanadium. R. Boettger has 

 found vanadium in variable proportions in 

 pisolithic iron in larger quantities than it was 

 hitherto supposed to exist. The ore, well-pow- 

 dered, is heated for a long time to rodnes- 

 nitre and soda. It is extracted with boilim; 

 water, and neutralized with nitric acid free from 



