باب صثة حل البارود يوخذ البارود الابيض النقى النارى مهما اردت وتاخذ طاجنين جدد ويحط فى الطاجن الواحد ويغمر بالماء ويوقد عليه نار لينة حتى يفتر وتطلع رغوته فارمها واوقد تحته جيدا حتى يروق ماؤه الى غاية ويقلب الماء الرايق قى طاجن اخر بحيث لا يتراك من التفل شى ويوخذ عليه وقدا لطيفا الى ان يجمد وتشيله وتصحنه ناعما ويوخذ الحطب الصفصاف اليابس يحرق ويغمر على صفة الحراق ويزن من البارود الثلثين والثلث من رماد الفحع الذى صحنته بالميزان ويعاد الى الطاجنين وان كانت الاعادة فى طاجن نحاس فهو اجود ويعمل عليه قليل ماء وتحمصه بحيث ان لا يلتزق واحذو من شرر النار ROGER BACON, _cir._ 1248. A. _Preparation of grough from natural saltpetre._ Carefully wash the natural saltpetre, and (as far as possible) remove all impurities. Dissolve it in water over a gentle fire, and boil it until the scum ceases to rise, and it is purified and clarified. Let the operation be repeated again and again, until the solution is clear and bright. Let it then deposit its crystals of the stone which is not a stone,[42] and dry them in a warm place. B. _Boiling the solution of grough saltpetre._ Pulverise the crystals of grough saltpetre thus obtained, and immerse them in water. Make a powder of two purifying substances in the proportion of 3:2. Dissolve the crystals over a gentle fire. F. _Use of wood-ash, charcoal, &c._ To the powder add some animal charcoal, and thoroughly incorporate the ingredients (in a vessel). Then pour the hot solution upon it, and your object (of clarifying the mother liquid) will be gained. C. _Removal of the insoluble impurities._ If (by its appearance and taste you judge that) the solution is good, pour it out (into a crystallising vessel, leaving the heavy impurities behind). G. _Crystallisation._ (The mother liquid is now allowed to crystallise.) H. _Stirring the depositing solution._ (While depositing), stir the solution with a pestle. Collect the crystals as best you can, and gradually draw off the mother liquid. The original is as follows:— Calcem diligenter purifica, ut fiat terra pura penitus liberata ab aliis elementis. Dissolvatur in aqua cum igne levi, ut decoquatur quatenus separetur pinguedo sua, donec purgatur et dealbetur. Iteretur distillatio donec rectificetur: rectificationis novissima signa sunt candor et crystallina serenitas. Ex hac aqua materia congelatur. Lapis vero Aristotelis, qui non est lapis, ponitur in pyramide in loco calido.