VOL. XXXVIII.] PHILOSOPHICAL TRANSACTIONS. 5g5 



He had a very pompous machine, which he calls machina Frobeniana, pro 

 resolutione combustibilium; inventa anno 1730. It is really an improvement 

 of the common bell, under which the oleum sulphuris per campanam is com- 

 monly prepared. This machine consisted of a concave plate of glass, ab, 

 fig. 13, pi. 16, with a hole in the middle c, which communicated by a glass 

 pipe CD, with a glass receiver eef, below the plate ab. On the plate stood a 

 massy golden tripus, sustaining a basin, about 4 inches diameter gh, having 

 within it another smaller one ik, of the same metal, about 2^- inches diameter; 

 this was heated a little. He then took small pieces of phosphorus out of a 

 basin of water, which he soaked up with brown paper, that the phosphorus 

 might be quite dry, which he put into a spoon, and flung it into the smaller 

 golden basin ik; where it immediately took fire. Then he lowered down a 

 large glass bell lmo, of about 18 inches diameter, and forming 3 quarters of a 

 sphere ; the rim lm being exactly ground to fit close on the plate of the glass 

 AB. This glass bell was suspended by a wooden circle pa pq, to which were 

 fastened 4 cords, that united into one knot at r, and from thence went a rope 

 over a pulley s, in the crown of the machine, which coming down by the side 

 of one of the pillars, served to raise up or let down the bell. 



At the first firing of the phosphorus, the whole bell appeared luminous, and 

 full of flame for a few minutes: when the deflagration of the first spoonful 

 was over, he flung in another, and so on, till 2 ounces of phosphorus were 

 consumed ; from which were sublimed a large quantity of flowers into the bell, 

 and some fell down on the concave glass ab. The bell at first felt cold, and 

 never became more than moderately warm. As the flowers began to cover the 

 inside of the bell to some considerable thickness, the flame was not seen 

 through so brightly as before, but the whole appeared of a light azure, or sky- 

 colour, which the doctor likened to the formation of the firmament: the flowers 

 sublimed he likened to snow. The bell then being drawn up again, and the 

 golden basins taken out, there remained in the smaller basin an almost fixed 

 red earth, or caput mortuum. On the admission of the cold air, the snow 

 flowers began soon to melt as per deliquium: which he compared to the forma- 

 tion of dew and rain; and as it dripped from the inside of the bell on the con- 

 cave plate AB, it ran through the hole in the middle at c, by the tube cd, into 

 the receiver eep; where it was collected in form of a clear transparent liquor, 

 somewhat clammy like gum-water, which he called water. 



Some of the flowers mixed with any combustible matter, as common olive 

 oil, &c. and put into a golden basin set over a lamp, fired immediately, and 

 flamed like phosphorus, being in reality phosphorus regenerated, and burnt 

 away to a substance like tar. 



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