er disclosed inventions that give any suggestion of novelty are
cross-referenced; but the primary purpose of a patent office
classification (to aid in determining patentability) has failed in this
instance.

In the imagined situation respecting pending applications, without doubt
diagnosis and classification upon the invention claimed is necessary to
effect the purpose of the office classification. Cross-referencing after
issue can not undo that which has been done.

If no application save that of the nail-machine be pending, no
duplication of patents occurs, but the labor of search is increased by
reason of the unfamiliarity of the examiner with the inventions he has
to search. After the patent is allowed he may find the entire
combination of the nail-machine without the counter disclosed in a
patent for a nail-making machine, so that as a nail-making machine this
new patent is of no value as a reference. Very probably all of the other
inventions illustrated (except the counter) are also old in their
respective classes; but the examiner of nail-making can not tell this
without extensive searches in those classes, so he notes
cross-references for them all.

_Difficulties due to varying ideas of claims._--Very troublesome
questions are constantly arising as to whether an invention should be
classified in a combination class or an element class. The point will be
illustrated by example: A describes and illustrates an automobile having
an internal-combustion motor and a friction-clutch in the motor
transmission-gear. He states that the clutch is in the usual
relationship to the motor and gearing, but claims a new clutch for
whatever it may be adapted. B discloses an internal-combustion motor
said to be for automobiles with transmission-gearing and a
friction-clutch and claims "in an internal-combustion motor a
friction-clutch," etc., specifying the form of the clutch. C makes the
same disclosure, but claims "an internal-combustion motor having a
specified clutch," while D, with the same disclosure, claims "the
combination with the internal-combustion engine of an automobile" of a
specified friction-clutch. E claims and illustrates only the
friction-clutch. Should these be classified together? If so, in what
class? Should a bearing composed of a specified alloy of copper, tin,
and antimony, be classed as a bearing or as an alloy? Should a house
painted with a mixture of linseed oil, lead oxid, and barium sulphate go
to