The perbromide is insoluble in ether, difficultly soluble in glacial acetic acid and, unlike the perbromide of cinchonidine dibromide, does not loose bromine on exposure to the air.

Dibromcinchonidine, C19H20Br2ON2, was prepared from the above perbromide by reducing the latter with sulphurous acid and precipitating the brominated base with ammonia. The dibromcinchonidine is extremely easily soluble in alcohol but can be recrystallized from a mixture of alcohol and chloroform.

Quinine dibromide, C20H24O2N2 Br2, is best prepared by a method similar to that of preparing cinchonine dibromide (Journ. pr. Chem., 63, p. 334; 68, p. 428). Ordinary (not anhydrous) quinine is dissolved in glacial acetic acid containing the theoretical amount of hydrobromic acid and to the solution is added the theoretical amount of bromine. After diluting the liquid with a little water a considerable excess of ammonium nitrate is added to the solution. The nitrate of quinine dibromide soon separates out and the free base can be liberated from the nitrate by means of ammonia.

By treating the quinine dibromide with silver nitrate or by prolonged boiling of the dibromide with lead acetate it is possible to remove one molecule of hydrobromic acid from the compound, but the resulting monobromquinine seems to undergo some change by this treatment as the free alkaloid thus obtained does not form any crystalline salts with acids.

Monobromquinine, C20H28BrO2N2, can be obtained by treating an alcoholic solution of quinine dibromide with an excess of alcoholic potassium hydroxide in the cold. The monobromquinine melts at 210°, is difficultly soluble in alcohol, has the specific rotation -118.1°, gives the thalleioquin reaction and forms fluorescent solutions. A hydrochloride of monobromquinine crystallizing with various amounts of water of crystallization, a hydrobromide crystallizing both with and without water of crystallization, a sulphate and an iodosulphate were also obtained.

Dehydroquinine, C20H22O2N2, was prepared by heating quinine dibromide with five parts alcohol and half a part of potassium hydroxide for twenty hours and then passing into the liquid a current of carbon dioxide.

The dehydroquinine was purified by converting it into the oxalate and setting the base free by ammonia. It gives the thalleioquin

reaction and forms fluorescent solutions. A hydrochloride and a herapathite of the dehydrobase were also obtained.

When treated with bromine dehydroquinine seems to be converted into dibromquinine, C20H22Br2O2N2. Journ. pr. Chem., 69, p. 193.

Cinchonine. P. Rabe and W. Denham find that when the iodomethylate of cinchonine is heated in acetic acid solution hydriodic acid is eliminated and methyl cinchotoxin is formed.

This transformation in acid solution is similar to the one which takes place in alkaline solution as observed by previous investigators (Claus and Miller, Ber. Dtsch. chem. Ges., 13, p. 2293; Freund and Rosenstein, Annal. Chem. Phar., 277, p. 279).

Ber. Dtsch. chem. Ges., 1904, p. 1674.

Zd. H. Skraup and R. Zwerger have tried to establish the structural formulas of the four isomeric bases: cinchonine, a-i-cinchonine, -i-cinchonine and allocinchonine. In a previous paper it had been shown that it is possible to ascribe to these isomeric bases such formulas as would account for the formation of one and the same hydriodocinchonine through the addition of hydriodic acid to any of them ond also for the formation of all these isomeric bases from this hydriodocinchonine when hydriodic acid is splitt off from it.

It can be seen that if the four isomeric cinchonine bases be supposed to correspond respectively to 1, 2, 3 and 4, the formation of all of them from the same hydriodocinchonine can be explained by assuming that the hydrogen which goes out together with the iodine comes from a different one of the numbered carbon atoms of the hydriodocinchonine for each of the iso bases.

On trying to verify these considerations by making a hydrochlor addition product of a-i-cinchonine and then splitting off again the hydrochloric acid, it was found that in the action of hydrochloric acid upon a-i-cinchonine the chief product is ordinary hydrochlor cinchonine and that only a small amount of hydrochlora-i-cinchonine is formed as a secondary product. It was also found that ordinary hydrochlorcinchonine is partly converted into hydrochlor-a-i-cinchonine when the former is heated under pressure with concentrated hydrochloric acid. It is therefore reasonable to assume that the little hydrochlor-a-i-cinchonine formed in the first reaction is only a product of transformation of ordinary hydrochlorcinchonine.

It was further found that on splitting off hydrochloric acid by means of alkali one and the same base, namely, cinchonine was obtained from hydrochlorcinchonine as well as from hydrochlor-a-icinchonine. This fact can of course not be explained by ascribing to the four iso-bases the formulas given above according to which we ought to get different bases from different hydrochlor derivatives. But as hydrochlorcinchonine is under certain conditions transformed

into hydrochlor-z-i-cinchonine no valid conclusions can be drawn from the products of the reaction with alkali.

On subjecting the other isomeric cinchonines to the action of hydrochloric acid only a little ordinary hydrochlorcinchonine was obtained but no isomeric addition products could be isolated.

On treating the three isobases of cinchonine with chlorine it was found that a- and -i-cinchonine did not react at all, but, that allocinchonine, like cinchonine itself, took up one molecule of chlorine giving dichloride of allocinchonine which was not identical with cinchonine dichloride. Monatshefte f. Chem., 1904, p. 894.

Northwestern University School of Pharmacy.

(To be continued.)

Note on Slaked Lime and Bleaching Powder.

By L. Reuter.

In Census Bulletin No. 210 on "Chemicals and allied products," there will be found on pages 48-49 the statement that burned lime used in the manufacture of bleaching powder is "so slaked as to contain from 24.5 to 25.5 per cent. of water." Correct in a certain sense as this information is, it seems to be necessary to call attention to the fact that 100 parts of calcium hydroxide of 100 per cent. always contain the equivalent of 24.3 per cent. of H2O corresponding to the formula Ca(OH)2, also that the H2O is chemically combined and cannot be considered as moisture or "water." As a matter of fact calcium hydroxide = Ca(OH)2 can be obtained is small hexagonal crystals if a solution of it be evaporated in vacuo. Crystals thus obtained were found to be "free from water" and to correspond strictly to the formula Ca(OH)2.

Furthermore it should be stated that slaked lime should contain no "water" at all, although in practice it contains from 0.5 to 1.5 per cent.

The following tables are the results of experiments made under my direction with different lime stones, while I was manager of a German factory producing about 10,000,000 lbs. of "chloride of

lime" per year. The first table shows the composition of slaked lime as actually used in the manufacture of bleaching powder, while the second gives the figures obtained in a series of experiments made on a carload scale for the purpose of ascertaining the quality of lime stone from different sources.

In regard to the further information given in the same bulletin namely that "100 lbs. of good lime yield 150 lbs. of bleaching powder" it should be stated that, if the figure 150 refers to bleaching powder of 110 degrees Gay-Lussac equal to 34.95 per cent. of available chlorine, this result will agree with the average yield obtained in practice; but if the percentage of chlorine be lower or higher, the yield will also, of course, be in proportion smaller or larger.

The manufacturing cost of slaked lime according to my own experience was M. 1.34 per 100 Kg. equal to 13.5 cents per 100 lbs.; and I should like to refer here to that part of my paper on chloroform published in No. 17 of The Oil, Paint and Drug Reporter of New York, April 27, 1903, where I made a statement in regard to the cheap "chloride of lime" used for making chloroform in factories producing at the same time bleaching powder.

In the factory above mentioned we used about 12% million lbs. of slaked lime per year. Of this quantity a little over 6% million lbs. were required for producing 10,000,000 lbs. of bleaching powder of 110 degrees; further 5.6 million lbs. were needed for manufacturing