FIXING AND PRESERVATIVE MEDIUMS 43 



ammoniac, half an ounce of which is quite sufficient to dissolve 

 several ounces of it. The following will be found of service, 

 and is probably an improvement upon Goadby's Nos. i and 2 : — • 



26. — Bichloride of Mercury and Potassium Nitrate (M.B.) 

 For Fishes, etc. 



Bichloride of mercury . . 4 grains 



Potassium nitrate (nitre or saltpetre) . 2 oz. 



Alum . . . . . I „ 



Sal ammoniac . ^ „ 



Water (boiling) . . . . i quart 



Dissolve the mercury with the sal ammoniac before adding the others, 

 and cool and filter before using. 



27. — Preservative for Algae (M.B.) 

 Borax . 

 Alum . 



Bichromate of potassa 

 Sodium chloride (common salt) . 

 Bichloride of mercury (saturated solution) 

 Water (warm) 



Allow to cool, and filter before using. 



Preserves the colour of seaweeds exactly and toughens 

 the specimens, and has been found valuable for preserving, 

 for a lengthened time, the colours of fleshy leaves of plants 

 — a great advantage when modelling from them. Another, 

 simpler in constitution but not quite so good, is — 



28. — Preservative for Algae (M.B.) 



Nitre .... 2 oz. 



Bichloride of mercury (saturated solution) i drop 



Water (warm) ... i quart 



Allow the mixture to cool, and filter as before. 



29. — Cupric Sulphate (Lo Bianco, p. 442) 



Cupric sulphate (sulphate of copper) . 5 or 10 parts 



Water (boiling) . . 95 or 90 , 



