86 KEPoiix— 1873. 



composition of the ether ; and of course this alcohol must be allowed for after- 

 wards. The author had proved that alcohol may be distilled out of a strongly 

 alkaline solution with great precision. He regarded this determination of alcohol 

 as one of the most precise in analytical chemistrj^ 



A second method, viz. tlie decomposition of ethers with hydriodic acid, was 

 proposed. This is applicable to the fats (i. e. the salts of glycerine) ; these ought 

 to yield iodide of isopropyl, which might be weighed, and the weight of which 

 would aflbrd a method of determining the proportion of glycerine in the fat. 



On the Manufacture of Chlorine by means of Mancjanite of Magnes'mm. 



By Walter Weldon. 



The process commences with the treatment together, in a still, of aqueous hydro- 

 chloric acid and a compound of peroxide of manganese and magnesia, which the 

 author calls manganite of magnesium. Chlorine is evolved, and there remains in 

 the still a mixed solution of chloride of magnesium and chloride of manganese. 

 This mixed solution is run off into a well, from which it is pumped into an evapo- 

 rating-pot, in which it is boiled down until it attains a temperature of about 300° F. ; 

 it is then run into a blind furnace, in which its evaporation is continued to dryness, 

 after which the dry residue is gently heated with access of air. Chlorine then 

 comes off, and there is at the same time reproduced manganite of magnesium, with 

 which the round of operations is then recommenced. 



Freliminary Note on the Preparation of Guaranine. 

 By John Williams, F.G.iS. 



The fruit of a South-American plant named the Paulina sorhilis is prepared 

 and made into rolls by the Indians of Pana. Its infusion is used as a beverage by the 

 natives, and has an action upon the system much like that of coH'ee or tea. These 

 rolls are found in commerce under the name of "Guaraua;" and within a few 

 months an infusion of this body has been strongly recommended as a cure for sick 

 headache. 



Dr. Stenhouse some years back examined this guarana, and separated its active 

 principle, guaranine, which he considers to be identical with theine or caffeine. 



Considering it a matter of some interest, the author determined to prepare some of 

 the guaranine, and first proceeded to do so by Stenhouse's process, which he found 

 was a troublesome one in some respects, and did not yield the body so white or pure 

 as was desirable ; and as animal charcoal refused to take up the colouring-matter, its 

 ultimate purification became a matter of some difficulty. This led him to devise the 

 following process, which proved very satisfactory. Guarana is reduced to very 

 fine powder and mixed with one third its weight of hydrate of lime, and then 

 moistened with water and allowed to stand for an hour or so, then placed in the 

 drying-closet and thoroughly dried at a very gentle heat. This dried mixture of 

 guarana and lime must now be tlioroughly exhausted by boiling benzole, and . 

 the benzole after filtration distilled oft'. A small quantity of light-coloured oily 

 matter is left, which must be treated with boiling water and placed in a basin, and 

 heated in the water-bath until all traces of benzole have been got rid of. The 

 liquid is then filtered through a proper filter so as to separate the oil, and the 

 coloui'less aqueous portion evaporated to a small bulk ; in twenty-four hours the 

 guaranine crystallizes perfectly white and pure, and requiring no further treatment 

 or purification of any kind. 



The treatment with a little lime and solution in hot benzole is also the best 

 mode of purifying the brownish guaranine produced by Stenhouse's process ; the 

 colour is retained by the lime, and the product is quite white. Guaranine in ap- 

 pearance much resembles cafi'eine or theine ; and there can be no doubt that it is 

 identical with those bodies. The author suspects, however, that it is rather more 

 soluble in cold water, not crystallizing quite so quickly as pure theine, and also that 

 it is not so bitter. He has, however, not attempted to make any comparative che^ 

 niical examination of the two bodies. 



