216 
APPENDIX. 
Fig 5. 
“ The upper part of the mortice in the shankj which re_ 
ceives the hinge of the wither, is here removed to show 
the lockings from which the joint derives its strength. 
Thus in figure 4, the wither A when expanded, locks 
against the fore part of the mortice, and at b against the 
septum in the back of the mortice, and at c against the 
other wither B ; while in addition to these lockings, the 
withers are kept in their place by a strong screw pin d : 
the upper surface of the wither B, and the lower surface 
of A are filed down at the joint part, to exactly one half 
of their original thickness, so as together to coincide 
to the thickness of the withers externally, and to form a 
single equal plane when closed. In figure 5 are two 
springs by which the withers are forced asunder; in 
striking this harpoon the withers collapse, and only make 
an opening three inches wide, but the moment a strain is 
applied to withdraw it, the points become inserted in the 
blubber of the whale, and by means of the inclined planes 
at A and B, (Fig. 4) together with the efforts of the 
springs, they are separated, as the instrument withdraws, 
to the width of 7 inches. In this harpoon, I conceive, that 
the joint, which in^ all other harpoons of the kind has 
been the failing part, is as perfect, and as strong as could 
be wished. Comprising less breadth than the common 
harpoon, it must be more easily thrust into the fish ; and 
making an opening only one half the size of the expanded 
withers, it will have less chance of retracting. The 
upon the pins ; for were the pins to be displaced, the harpoon, once 
fixed in the fish, would retain its hold by the withers being morticed. 
