250 ROSACEA. 



page, in which 28 cwt. of ahnonds were treated, the yield of essential 



87 per cent. From data obligingly furnished to us 



Herring's and Co 



yield 



The yearly averages as taken from the books of this firm, show that it 

 may be as low as 074, or as high as 1*07 per cent., which, assuming 57 

 pounds of cake as equivalent to 100 pounds of almonds, would represent 

 a percentage from the latter of 0'42 and 095 per cent, respectively. 

 Mr. Umney explains this enormous variation as due in part to natural 

 variableness in the different kinds of bitter almond, and in part to their 

 admixture with sweet almonds. He also states that the action of the 

 emulsin on the amygdalin when in contact with water, is extremely 

 rapid, and that 200 pounds of almond marc are thoroughly exhausted 

 by a distillation of only three hours. 



In the distillation, the hydrocyanic acid and bitter almond oil unite 

 into an unstable compound. From this, the acid is gradually set free, 



and formic acid. Sup- 



almonds 



ammonium 



yield 0*2 per cent, of hydrocyanic acid. Pettenkofer oLtained by 



17 



Some manufacturers apply bitter almond oil deprived of hydrocyamc 

 acid, but such purified oH is very prone to oxidation, unless carefully 

 deprived of water by being shaken with fused chloride of calcium. The 

 sp. gr. of the original oil is 1'061— 1'065 ; that of the purified oil 

 (according to Umney) 1'049. The purification by the actiou of ferrous 

 sulphate and lime, and re-distillation, as recommended by Maclagan 



occasions, we are informed 



(COH), being the aldehyde of benzoic acia, 

 C^H^COOH), is easily converted in that acid by spontaneous or 

 artificial oxidation. The oil boils at 180° 0. and is a little soluble m 

 water ; 300 parts of water dissolve one part of the oil. .,, 



There are a great number of plants which if crushed, moistened am^ 

 water, and submitted to distillation, yield both bitter almona w 

 and hydrocyanic acid. In many instances the amount of ^y^^?^^j^g 

 acid is so extremely small, that its nresence can only be revealed by 



most delicate test,— that of Schonbein. 



hydrocyani 



Pomec^ 



mentioned. , . ^ 



Euph 



yield hydrocyanic acid. , . ro-mn 



rdinia xeranthemoides Desf., growing m tneya^^F , 



■egions, has been shown by W 



acid.' 



w 



ith 



has been observed by the French in Gaboon 

 of Ximenia americana L. of the order Olaciii^^^ 



I Applied iii the following manner :— Let tense blue coloration m the pr 



bibulous paper be imbued with a fresh tine- hydrocyanic acid. , Moscon, 



ture of the wood or resin of guaiacum, and » Bull, de la Soc. imp. des nat. a<^ 



alter drying, let it be moistened with a xxxv. (1862) ii. 444. .ort -Prod'tia 



Bolutiou composed of one part of sulphate » Exposition Univers. de l^i- 



of copper m. 2000 of water. Such paper <lr.^ Colonies Frani-aises, 92. 



Such paper 

 with water will assume an in- 



