46 MADRAS FISHERIES BULLETIN VOL. XIV, 



the great advantage of continuous movement in accelerating the 

 rate of freezing was recognized. 



Wallem's second model was designed to obviate the crudity and 

 inconvenience of rolling the barrel about on the ground. The later 

 invention consisted of mounting the barrel lengthwise upon 

 supports in such a way that it could be revolved readily by means 

 of a handle attached to the end of an axial rod fitted at one end of 

 the barrel. A square opening, provided with a hinged lid, permit- 

 ted of the filling and emptying of the barrel. Whether Wallem's 

 system was ever utilized commercially I do not know, but it is 

 obviously directly related to the method elaborated in 1918 by the 

 Food Investigation Board at Billingsgate Market, London, in the 

 basal idea utilized in the latter design of a revolving cylinder 

 provided with baffle plates \.3) to keep the fish in motion during the 

 duration of the process. The main differences are a ^'reat elabora- 

 tion of the mechanical perfection of the process and the substitution 

 of brine for the salt and ice mixture. 



In its simplicity and adaptability to varying commercial needs 

 by the provision of two different types of machine, this British 

 design appears to be the most satisfactory of any until now devised. 

 In its simpler form as seen working this apparatus consists of a 

 number of large fish containers in the form of cylinders with per- 

 forated walls, revolving horizontally in a tank filled with brine. 

 This tank has double walls at the bottom and both ends 

 Evaporator coils fill the space between the floors ; that at one end is 

 fitted with a filtering arrangement, while at the other are fitted one 

 or more propellers to ensure the movement and circulation of the 

 brine. The walls of each cylinder are made either of galvanized 

 wire netting or preferably of galvanized iron plate with perforations 

 of about % inch diameter. Part of the cylinder wall is hinged in 

 order to provide an opening for filling and unloading the cylinders ; 

 in the inside three baffle plates, made of sheet iron, extend the whole 

 length of the cylinder .vide Wallem's design of a barrel with 

 similar baffle plates). The cylinders when required to be unloaded 

 can be lifted out by hooks worked from an overhead crane. In 

 the case of an apparatus of large size consisting of several cylin- 

 ders, each may be filled with different kinds of fish requiring 

 different times to freeze. The whole apparatus is placed in an 

 insulated casing, with removable covers- 



