Subject: What is the origin of the terms 12 AM and 12 PM?

The unscientific terms 12AM and 12PM have crept into use over the last 15 
years.  Many in the scientific community oppose this corruption of the times 
noon and midnight.  I am in this group.  12 AM means 12 hours before the 
meridian and 12 PM means 12 hours after the meridian.  Both these terms define 
midnight.  The meridian being noon.  I have asked government agencies and 
scientists about this problem.  None have provided me an answer and some just 
ignore the question.  In order to fix the problem the origin needs to be 
determined.  Did an agency, an employee, a technician start this?  Can you 
answer this question?  I am doing this to maintain scientific accuracy.

Re: What is the origin of the terms 12 AM and 12 PM?