It is but right to state that the above method has been objected to by
a practical workman, whose business has led him to study the matter
closely. He states that it is impossible in this way to effect the
desired object. As the writer has not been able to test the working
of the apparatus on his own lathe, he felt inclined, at first, to
withdraw the whole chapter. The objections offered, however, were
not, to his mind, entirely satisfactory; and the opinion of other
equally scientific and practical men being favourable, the chapter
has been retained. It is possible, nevertheless, that there may be
a mathematical reason which the writer is not competent to work
out, and the objector being a man of great mechanical knowledge and
experience, his remarks are worthy of consideration. The practical
(not insuperable) difficulty appears to be the production of a proper
tool for this work.