Historical clue formulations

• Old lab burners — 2022-08-07
• Old lab burners — 2015-03-29
• Old lab burners — 2014-03-30
• Old lab burners — 2013-06-21
• Old lab burners — 2012-07-12
• Lab burners of old — 2010-07-27
• Old lab items akin to Bunsen burners — 2008-01-26
• Old lab burners — 2007-09-02
• Old lab burners — 2005-02-27
• Old liquid heaters — 2004-03-06
• Lab burners — 2003-10-15
• Old flask heaters — 2003-08-15
• Old lab heaters — 2002-03-26
• Old science lab equipment — 2001-05-26
• Lab heaters — 2001-05-15
• Alcohol burners — 2000-12-08
• Lab equipment — 1999-07-24
• Small heaters — 1999-02-14
• Cone-shaped heaters — 1998-01-18
• Old-fashioned heating devices — 1997-11-30
• Cone-shaped heaters — 1997-08-07
• Lab burners — 1995-05-15
• Lab burners — 1995-02-26
• Lab heaters — 1995-01-12
• Lab burners — 1994-11-28
• Lab burners — 1994-04-02