624 PHILOSOPHICAI. TRANSACTIONS. [aNNO 16Q3-4. 



^n Account of Books, viz.* — /. Martini Lister, Exercitatio Anatomica, in qua 

 de Cochleis, maxim} Terrestribus, et Limacibus agitur. Omnium Dissectiones 

 Tabulis ceneis, ad ipsas Bes affabre incisis, illustrantur. Cui accedunt Digres- 

 siones de Respiratione, Generatione, Androgynd, Sapid, Loligine, et Polypo, 

 aliisque Rebus naturalibus, 8vo. i6Q4. N° 208, p. 65. 



//. A Treatise of the Natural Grounds and Principles of Harmony. By JVill. 

 Bolder, D. D. &c. Land. 6vo. \6q4. N°208, p. 67. 



The author observes, that sounds, the material part of harmony, are natural 

 and physical ; but the disposing of them so as to delight the hearing, is the 

 formal part of it; both united make harmony complete; and it may be either 

 in symphony, when many sounds are heard together, or solitary, where the ear 

 finds the agreements of single, proceeding with subsequent harmonious notes. 

 The physical reason of this pleasing agreement of sounds, is the design of this 

 tract. 



After treating of the several parts of this science in 8 chapters, in the con- 

 clusion he has summed up his whole doctrine: that is, bodies by motion make 

 sound; sound of bodies fitly constituted make tone or tune; tune is acuter by 

 swiftness, graver by slowness of vibrating motions. The proportions of these 

 are best found by strings ; if two vibrations be commensurate within the N° 6, 

 they produce concords; if incommensurate, they make discords. Concords 

 are limited, discords infinite. 



It was not his design to meddle with the metric part of music, concerning 

 composition, air, and humour: nor to treat of the receptive faculties of per- 

 sons from the difl^erent constitution of their organs of hearing; nor to show 

 why some have and others want musical ears; nor to treat of other curious 

 speculations concerning music, which will afford the acutest philosopher business 

 enough; but only to treat of this ground-work of all, the stating of the true 

 proportions of musical tones, both harmonious and discordant, such especially 

 as are usually comprised in the scales, and applied and used in music. 



A Letter from Hans Sloane, M. D. and S. R. S. with several Accounts of the 

 Earthquakes in Peru, Oct. 20, 1687 ; and at Jamaica, Feb. \g, l687-8 ; and 

 June 7, 1692. N° 209, p. 78. 

 These papers were 8 in number, mostly written by eye-witnesses of those 



dreadful events; abstracts of which are as follow: 



• In this vork of Lister, which is now become rare, the anatomy of several species of snails and 

 slugs is accurately detailed, and is accompanied by many ingenious observations. 



