681 



would he have felt the astonishment, and entertained the suspicions 

 which he so strongly expresses, on his perusal of Cavendish's memoir 

 in March 1784. 



De Luc's account in the " Meteorologie," it must also be observed, 

 is not a contemporaneous one, published at the time of Priestley's 

 communication in 1782, and before the conclusions of Watt were 

 made known ; but is given from memory, at an interval of several 

 years, when such a mistake as that of June for January shows how 



little it can be relied on. 



I am, &c. 



JAS. P. MuiRHEAD. 



II. " New Volatile Organic Acids, from the Berry of the 

 Mountain Ash." By A. W. HOFMANN, LL.D., F.R.S. 

 Received February 3, 1859. 



Whoever has been engaged in the preparation of malic acid from 

 the juice of the unripe berries of the Mountain Ash (Sorbus Aucu- 

 paria), cannot have failed to perceive the peculiar powerful odour 

 evolved during the evaporation of the liquid partially saturated with 

 lime. The body to which this odour belongs was hitherto un- 

 known, and only lately, my friend and former pupil, Dr. George 

 Merck of Darmstadt, when preparing malic acid on a large scale, 

 conceived the happy idea of evaporating the liquid in a distilling 

 apparatus. He thus obtained an acid distillate, from which he suc- 

 ceeded in separating an oily body possessed of acid properties. To 

 the kindness of Dr. Merck I am indebted for an appreciable quan- 

 tity of this remarkable body, which has enabled me to examine its 

 properties and establish its composition. 



The preparation of the oil from the aqueous acid obtained by 

 distilling the mother liquor of the bimalate of calcium, presents no 

 difficulty. The liquid is saturated with soda, evaporated and mixed 

 with dilute sulphuric acid, when the oil rises as a brown layer to the 

 surface of the liquid. It is separated by ether, and after the volati- 

 lization of the latter, submitted to distillation. The first portions 

 of the distillate contain appreciable quantities of water ; the thermo- 

 meter, however, rapidly rises above 200 C. What now distils is a 

 perfectly pure compound, which, on redistillation, exhibits a con- 



