Consider the following statements relating to hydraulic gradient line and energy gradient line :

1. In the case of a fluid flowing in a pipeline, hydraulic gradient line and energy gradient line may coincide.
2. The line joining the points representing piezometric heads is known as hydraulic gradient.
3. In the case of ideal fluid, energy gradient line is always horizontal.
4. Hydraulic gradient line has a downward slope in the case of flow through pipes.

Of these statement