APPARATUS ’FOR DETECTION OF ADULTERATIONS IN COFFEE. 141 
' The jury answered the first and last questions in the affirmative, and the three inter¬ 
mediate ones in the negative, and his Lordship therefore directed a verdict to be entered 
for the plaintiffs on the first and second counts, and for the defendants on the third, the 
defendants’ counsel having leave to move, and the damages to be referred. 
ON AN APPARATUS FOR THE DETECTION OF ADULTERATIONS IN 
COFFEE. 
BY JOHN C. DRAPER, M.D., 
PROPESSOR OP NATURAL niSTORY, COLLEGrE OF THE CITY OP NEW YORK, AND OP 
ANALYTICAL CHEMISTRY IN THE UNIVERSITY OP NEW YORK. 
To the Editors of the Philosophical Magazine and Journal. 
College of the City of Neio York, June 1, 1867. 
Gentlemen,—Having been engaged during the past winter in the examination of 
specimens of adulterated coffee, I have contrived an instrument which has been of con¬ 
siderable practical value in enabling me to obtain satisfactory results with great rapidity. 
Thinking it may prove interesting to some of your readers I enclose a description of it, 
which was read at a recent meeting of the New York Academy of Medicine. 
It consists of a tube (a b ) 1 inch in diameter and 8 inches in length, which terminates 
below in a narrow tube ( b c) £ of an inch in diameter and 4 inches in 
length ; the lower small opening ( c) is closed by means of a cork to a 
certain point, from which it is graduated to tenths of a cubic centimetre: 
a number of these tubes, with a suitable stand and a small measure 
holding one cubic centimetre, complete the apparatus. 
When it is to be used, the tube is closed below, and filled to within 
half an inch of the upper extremity ( a ) with cold water (that has been 
boiled to expel the gas, and kept in a well-stoppered bottle to prevent 
its reabsorption); a cubic centimetre of the sample of ground coffee 
under examination is then cautiously dropped on the surface of the 
water, when we should notice (1) whether it sinks quickly or slowly ; 
(2) what tint and odour it imparts to the water; (3) the expansion in 
bulk as measured in the graduated small tube ; (4) the change in colour 
of the grounds, and whether they collect loosely or not. 
If it is good coffee and a pure article, it floats on the surface for a 
considerable period, and if freshly roasted and ground will often remain 
suspended for days if the tubes are kept free from agitation. In the 
majority of instances it falls in a few hours, and imparts to the water 
in the large tube a delicate amber tint and a faint coffee-like odour, 
each particle as it rests in the small tube retaining its outline, indivi¬ 
duality, and colour, and the increase in bulk being about one-half a 
cubic centimetre. 
If it is chicory, it sinks instantly, nearly the whole mass tumbling into 
the small tube in a single minute, and even in its rapid passage through 
the water imparting to it a deep brown colour, and an odour somewhat like that of 
liquorice. The tint of the particles is, at the same time, altered greatly ; the expansion 
of the mass is also very considerable, its bulk in a short time increasing to nearly two and 
a half cubic centimetres ; and the particles, losing their individuality, seem to fuse to¬ 
gether and form a mass almost without interstices. 
By preparing mixtures of chicory and coffee in different proportions, we find that the 
first sinks rapidly, while the latter remains suspended for a considerable period, though 
a small portion may be carried down by the chicory in its sudden subsidence. After a 
time (which may be shortened if desired, by agitating the tube) the coffee sinks also ; 
and by noticing the proportion of compact and loose sediment in the small tube, and 
the position of the line of meeting of the dark- and light-coloured solutions, we obtain 
an indication of the proportion of chicory to coffee, which coincides very nearly with that 
employed in making the mixture. The tint of the fluid in the large tube and the in¬ 
crease in the bulk of the solid matter are also of use in arriving at a correct estimate. 
After the performance of a few experiments with mixtures of coffee and chicory in dif- 
