Scort—On a Method for Colouring Lantern Slides. 265 
thickened with dextrine to give a body to the colour: about 10 per 
cent. dextrine is sufficient; the glasses should be well cleaned 
before writing. In a compound diagram, if the first colour be 
allowed to dry, other colours may be rapidly written over the 
former ones without risk of removing them. For these inks any 
colour may be used. Iodine green and eosin inks make a parti- 
cularly brilliant contrast. A very good dark ink, not absolutely 
black, may be made from Antoine’s “ encre noire,’”’ made slightly 
alkaline with ammonia, and thickened with 10 per cent of 
dextrine. 
