464 PHILOSOPHICAL TRANSACTIONS. [ann6 1 67O. 



trembling earth,) it may be validly inferred, that the earth has a diurnal pro- 

 gressive motion from west to east. 



. III. Quaestio Triplex de Anno Mense et Die Christi Nati, Baptistati et Mortui. 

 Auth. R. P. Michaele Seneschallo e S. J. Leodii, 1670, in 4 to. 



This author undertakes to prove, in this chronological treatise, not only the 

 year and month, but also the day and hour of the nativity of Christ, and of his 

 baptism and death. 



IV. Hernianni Grube, M. D. Commentarius de Modo Simplicium Medica- 

 mentorum Facultates cognoscendi. Hafniae et Francofurti, i66q, 8vo. 



In this treatise there is nothing interesting to medical men of the present 

 times. 



V. De Lacte Lunae Dissertatio Medica, Johannis Danielis Majoris, Ph. et 

 M. D. Kiloni, 1667, 4to. 



. By the word lac luna3 nothing else Is meant here than flores argenti, or a 

 fine white porous and friable earth, insipid and without scent, dissoluble in wa- 

 ter, and tinging it with a milky colour, and sometimes raising a kind of ebulli- 

 tion in it, found commonly in silver mines, and in them sublimed and sticking 

 to the roofs of the rocky hills; having a drying and abstersive quality, and 

 therefore good against the afflux of sharp humours in ulcerated parts, serving 

 also for an excellent cosmetic. All which particulars are at large deduced and 

 discoursed upon by the author ; who observes, that Gesner in his book of Fos- 

 sils takes good notice of this mineral earth, and affirms it to be found in the 

 mountains of Helvetia, especially that which is called mount Pilate. From whom 

 he thinks that others, as Boethius a Boot, Olaus Wormius, Aldrovandus, Cal- 

 c^olarius, and others, have taken the hint. 



He makes the matter of this earth to be the metallic vapours of silver ore, by 

 some fermentation raised and sublimed, and then condensed.* 



Extract of a Letter of Dr. John IVallis to Robert Boyle, Esq, 

 concerning the Doctor s Essay of Teaching a Person Dumb and Deaf 

 to speah and to understand a Language, with the Success thereof. 

 N^ei, p. 1087. 



The task consists of two very different parts; each of which renders the other 

 more difficult. For, besides that which appears on the first view, to».teach a 

 person who cannot hear to pronounce the sound of words ; there is that other, 



* What is here termed lac lunae appears to have been a calcareous earth. It was not soluble in 

 water, but merely diftusible through it. Its supposed origin from ** the metallic vapours of silver 

 fermented, sublimed and condensed," is an egregious error. 



