How to change the time bound of scheduler

In scheduler the time division is 24 hrs. In my scheduler I require only morning 7a.m to evening 7 p.m . To do this where should I change in my scheduler.

scheduler.config.first_hour = 7; scheduler.config.last_hour = 19;

Thank you for your help.But the view now shows only 7.00 a.m to 7.00pm.I want the view to remain from 00.00 to 23.00 hrs.But the default view must be from 7.00hrs to 19hrs when i load the calender and i can see all the other timings if i scroll up or down.

scheduler.config.scroll_hour = 7;