40 MADRAS FISHERIES BULLETIN VOL. XIII , 



These again may be differentiated by the mode of manufacture, 

 viz. — 



{(/) soldered cans ; and 



(e) solderless or ' sanitary ' cans made either wholly or 

 partially without solder. 



Or again they differ according to the method of opening, 

 such as 



(/) keyless, 



ig) key-openers, 



(//) tear or strip-off cans, 



(/) full opening or capped cans, 



(./■) lever tops (though these are not capable of full hermetical 

 sealing unless soldered round the cap), 



{k) screw top. Phoenix, etc., cans, which however are glass jars 

 or bottles only. 



Finally they may be either plain inside or lacquered (so-called 

 ' enamelled ') to prevent chemical action. 



11. As will be shown below, much depends upon the selection 

 of proper shapes and sizes of cans; profits depend largely on this 

 matter since with equal contents there may be great waste of 

 plate, solder, labour, time, and fuel (in processing) by a wrong 

 selection or by using improperly designed cans. Of course, profit 

 also depends on the capacity of the cans, since cans similarly 

 designated (e.g., 'quarters '; see below) may hold anything from 

 4 to 7 oz. nett of fish ; this is a matter for the public. 



12. In the United States of America certain standards are 

 generally recognised, which, as regards the usual contents, are 

 somewhat conventional. They either bear numbers which refer to 

 conventional standards or are called I lb., 2 lb., I gallon, etc., 

 probably relating to their contents in water, since the contents of 

 fish, etc., vary considerably from the nominal capacities. For 

 those who wish to order cans from the manufacturers it is neces- 

 sary to consult the standard tables, an extract from which is here 

 given, but slight differences are observable in different text books 

 or trade lists. 



