73 
Some results have already been obtained, both by this and 
by another form of apparatus, but they need further confirma- 
tion before they are made public. Hitherto, the Author had 
been chiefly engaged in overcoming those practical diflficulties 
which beset the commencement of all new methods of experi- 
menting, especially where such extreme accuracy and delicacy 
of manipulation are essential. 
The experiments had been arranged with the co-operation 
of Mr. Thomas Tate, F.R.A.S., and were being carried out 
with great care by the Authors assistant, Mr. Unwin, under 
his own immediate direction, and he hoped for results of high 
scientific importance and great practical utility. 
