622 



APPENDICES. 



Fig. 249.— Vebtical Mioeo-Photogbaphic Apparatus. 



(F) Sterilisation Apparatus. 



Steam-steriliser. — A cylindrical vessel of tin about half a metre 

 or more in height, jacketed with thick felt, and provided with a 

 conical cap or lid (Fig. 250). The lid is also covered with felt, has 

 handles on either side, and is perforated at the apex, to receive a 

 thermometer. Inside the vessel is an iron grating or diaphragm 

 about two-thirds the way down, which divides the interior into 

 two chambers— the upper or " steam-chamber," and the lower oi- 

 " water-chamber." A gauge outside marks the level of the water 

 in the lower chamber ; this should be kept about two-thirds full. 



