No. 2 (1921) REMARKS ON CANNING 5I 



All figures are near approximations, small fractions being 

 omitted ; cans in different factories differ so considerably that 

 absolute exactness is impossible. The French half is somewhat 

 larger and holds more fish than item 7 in the table. 



34. Column (3) represents over-all measurements and not inside. 

 Column (4) represents actuals as many times tested, the cylindrical 

 cans usually holding slightly more than the contents quoted. 

 Column (5) gives the cubic capacity inside with the cover fixed and 

 is not arrived at by multiplying the figures of column (3). Column 

 (6) gives the area of the tin plate actually found in the cans : it is 

 somewhat larger than the figure arrived at by multiplying the 

 figures of column (3) since the tops and bottoms have curled rims of 

 about % inch depth, which adds to their surface area. The 

 waste involved in cutting tops and bottoms from a plate has not 

 been included. The length in column (7) gives the length of the 

 solder seams, and includes the side seam of the body as well as 

 those uniting tops and bottoms to the body. 



35. It is now possible to compare shapes and sizes with cost in 

 tin plate and solder and with capacity and contents. For instance 

 if a quarter be only % inch in depth instead of the full I inch, it will 

 hold only 4 ounces of fish as against 7 in the full sized tin and yet 

 demands considerably above three-quarters (37/44) of the tin 

 plate and practically as much solder as the larger tin. The badly 

 designed half. No. 5, holds 13^ ounces of fish as against 13 ounces in 

 No. 6 which is an ordinary ' quarter ' sized can but of double depth ; 

 yet No. 5 takes 78 square inches of tin and 42 inches of soldered 

 seam against 62 and 31 for No. 6; No. 8 cylindrical compares 

 still more favourably with No. 5. Numbers 8, 9, and 10 like No. 6, 

 show the value of increasing the capacity by increasing the depth ; 

 No. 8, a I2-ounce cylindrical tin of 1% inches inside depth and 

 24 inches cubical capacity, takes 60 square inches of tin plate and 

 30 inches of soldered seam, while No. 9 holds double, viz., 50 cubic 

 inches, with an increase of only one-third of tin plate and 1/30 of 

 solder seam. The reason of course is that while the tops and 

 bottoms remain the same in area, the capacity is exactly doubled, 

 etc., by simply increasing the width of the strip which forms the 

 body. 



36. Apart from the saving effected by a judicious selection of 

 the sizes and shapes of cans, it is obviously to the interest of both 

 canner and consumer to use tins as large as are found suitable to 



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