Step 1 :The function $f(x)=\log (-x)+4$ is compared to the parent function $f(x)=\log x$ to identify the transformations.
Step 2 :The negative sign in front of $x$ in the function $f(x)=\log (-x)+4$ indicates a reflection over the y-axis.
Step 3 :The addition of 4 to the function $f(x)=\log (-x)+4$ indicates a vertical shift up by 4 units.
Step 4 :\(\boxed{\text{The transformations that have occurred are: reflection over the y axis and up 4 units.}}\)