History is diachronic. Science is synchronic.
History is a narrative of time. Science is a theory of space.
A scientist sees two things and notices their similarities. An historian sees two things and notices their differences.
A scientist seeks what is universal that explains. An historian seeks what is unique that explains.
For science the default inference is to a universal nature. For history the default inference is to a unique particular.
A history of science is not a science. A science of history is not a history.
Historical science universalizes recent history. Historicism particularizes universal science.
Scientific history, or a science of history, is pseudo-history because it devalues particulars and overvalues universals.
Evolution is a theory of history presented as a science. Whig history is a philosophy of science presented as a history.