DETECTION AND ESTIMATION OF TANNINS. 45 
As glass is liable to fracture in the above boiling, a 
kettle of what is known in this country as “agate¬ 
ware” has been found very satisfactory. The infusion 
may also be prepared in an apparatus described by 
Yon Schroder (Fig. 1), which consists of a cylindrical 
Fig. 1. 
cast-tin vessel 12.5 cm. high and 7 cm. in diameter, 
with a spout but no handle; the latter is omitted in 
order that the vessel may be more readily heated in a 
water-bath. Accompanying this is a strainer or plunger 
of the same metal, with a handle about 16 cm. in length. 
The strainer is of such diameter that when covered 
with muslin it will just fit the inside of the cylindrical 
vessel and play the part of a piston to it. Five, ten, 
or twenty grammes of the powdered material are placed 
in the vessel, 200 cc. of cold distilled water added, and, 
