Experiments with crystals - some time lapse photography used to show them growing.
Story about various types of frosts.
First are the tiny frost crystals of "hydrochloric acid". A drop of the acid is placed on a piece of glass. A drop of ammonia is added. Smoke emerges from the drop and crystallising takes place. The glass slide is placed under the microscope. We see the crystals growing (may be time lapse photography). They make fern-like shapes. We see more crystals growing.
Salt crystals are shown growing under the microscope. Sodium Sulphide crystals are next. The famous "pyramid" crystals of sodium carbonate are shown.
Was an item in Pathe Pictorial issue number 648.