Phosphorescence 315 



for nearly a century, until Zanotti (1748) , with a group of Italian 

 scientists in Bologna, started reinvestigation of phosphors. 



About the same time another Italian, Father Benedictus Mazzotta 

 of Bologna, devoted a short paragraph to the Bolognian phosphor 

 in his book De Triplici Philosophia, Naturali Astrologica et Minerali 

 (Bononiae, 1653) , often referred to as Philosophia Triplex. 



COUNT MARSIGLI AND OTHER ITALIANS 



The first paper on the Bolognian stone in Italian, entitled II Fos- 

 foro O'vero la Pietra Bolognese, Rome, 1680, was written by Marc 

 Antonio Cellio, professor of astronomy in the Physico-Mathematical 

 Academy of Rome. Cellio ^^ described the places where the Bono- 

 nian stone was found, chiefly on Monte Paterno, and said they were 

 usually the size of oranges, but there was one in Aldrovandi's Mu- 

 seum weighing two and a half pounds, and he had one weighing 

 five pounds. The color of the stones varied, but white ones were 

 best for preparing a sensitive phosphor by a method which he de- 

 scribed. As a result of such preparation, even the light of a candle 

 or moonlight would be absorbed. Cellio told how to make lumi- 

 nous pictures by mixing the powdered phosphor with egg white and 

 drawing on any surface desired. Figure 31 is the frontispiece to his 

 book. Note that the pictures and the preparation of the phosphor 

 are shown. 



The second paper in Italian, containing many figures of the 

 mineral, entitled, Dissertatione epistolare del fosforo minerale e 

 sia della pietro bolognese, etc., appeared in 1698. It was written 

 by Count Luigi Fernando de Marsigli (1658-1730), the distin- 

 guished naturalist, mathematician and soldier, who founded the 

 Bolognian Institute of Sciences and Arts. Marsigli had planned to 

 write the booklet (see title page as fig. 32) as a present for Boyle 

 but it was laid aside after Boyle's death in 1691, and only published 

 in 1698. A presentation copy was abstracted in the Philosophical 

 Transaction ^^ for 1698. A point emphasized in the abstract was 

 that " The Stone shines in Water and receives the Light in Oyle of 

 Nuts, but will not emit it till it be out of it." This last statement is 

 hard to understand, as most phosphors will shine in any liquid 

 medium which does not distintegrate them. 



Count Marsigli and others had thought that the Bolognian stone 

 imbibed less light from the direct rays of the sun than from reflected 

 beams, but this opinion was probably connected with light adapta- 



^^ A review of the book is given in the Hutton, Shaw and Pearson abridgment of 

 the Phil. Trans. 2: 215 f., taken from the Philosophical Collections, No. 3: 77-79, 1680. 

 " Phil. Trans. 20: 306, 1698. 



