362 
PROFESSOR O. REYNOLDS AND MR. W. H. MOORBY 
this means a head of 11'3 feet of water was maintained at the thermometer bulb, and 
at a temperature of 220° Fahr. I had not much trouble with bubbles of vapour. 
The Tivo-way Tip 2 nng Switch. —(Part 1., par. 16.) 
11 . This was constructed to provide a means of rapidly diverting the water at 
will, either to waste or into the tank. It consisted, as shown in the sketch, of two 
curved copper pipes of rectangular section, meeting at their upper ends at an angle 
of about 30°. Their common side was produced for about f inch, and formed into a 
knife-edge, separating the two orifices. 
Fig. 5. 
These pipes were rigidly connected to a wooden link which w'orked about a. 
horizontal axis, distant 2.^ inches below the knife-edge. Wooden stops \vere pi’o- 
vided to limit the swing of the switch to rather less than 2 inches. One arm of the 
