between the fixed toe or fluke and the longer fluke jointed into it.
This is now avoided by embracing the short fluke within the longer one.
The shank, formerly screwed into the boss, is now pushed through and
kept up against the collar of the boss, by the volute spring, which at
the same time presses back the hinged flukes after being displaced by
a rock. The shank can now freely swivel round, whereas before it was
rigidly fixed. The toes or flukes are now made of soft cast steel, which
can be straightened if bent, and the boss is made of cast steel or
gun-metal.

[Illustration: JAMIESON'S GRAPNEL.]

* * * * *




WRETCHED BOILERMAKING.


_To the Editor of the Scientific American_:

As long as I have been a reader of the SCIENTIFIC AMERICAN I have been
pleased with the manner in which you investigate and explain the cause
of any boiler explosion which comes to your knowledge; and I have
rejoiced when you heaped merited censure upon the fraudulent
boilermaker. In your paper in December last you copied a short article
on "Conscience in Boilermaking," in which the writer, after speaking
of the tricks of the boilermaker in using thinner iron for the center
sheets than for the others, and in "upsetting" the edges of the plates