202 NOVUM OllGANUM. 



Proponendum itaque cst jam exemplum instantite 

 nrirjrnntis. Sit natura inquisita, candor, sive albedo; 

 intifrntfia iniqrans ad generationem cst vitrum inte- 

 gruin, ct vitrum pulverisatum. Similitcr, aqua simplex, 

 et aqua agitata in spumam. Vitrum euim intcgruni, 

 et aqua simplex, diaphana sunt. non alba: at vitrum 

 pulverisatiini, et aqua iu spuma, alba, non diaphana 50 . 

 Itaque qiuvreudum, (piid acciderit ex ista migratione 

 vitro, aut aqua\ Maiiifcstum enim cst, formam albe- 

 dinis deferri et invehi ]&amp;gt;er istam coutusioncm vitri, ct 

 an-itationom aquiv. Nihil autem reperitur aecessisse, 

 prater comminutiouem ])artium vitri ct aqu;v, ct aeris 

 insertioncm. Nequo vero panim profectum est ad in- 

 veniendam formam albcdiuis, quod corpora duo per se 

 diaphana. sed secundum niagis ct minus, (aer scilicet 

 et aqua, aut acr ct vitrum) simul posita per minutas 

 portiones, cxliibeaut albediucm, per refractioncm iiw- 

 qualem radio rum lucis. 



Ycrum liac in re proponendum est etiam exemplum 

 pcriculi et cautionis, dc (piibus diximus. Nimirum 

 facile hie occurret intcllcctui ab hujusmodi efficienti- 

 bus depravato, quod ad formam albcdiuis aer semper 

 rcquiratur; aut (jiiod aliu do genoretur tantum per 

 corpora diaphana: qu:v omnino falsa sunt, ct per mul- 

 tas exclusioncs convicta. Quin ])otius apparebit, (misso 

 acre, et hujusmodi) corpora omnino a^qualia (secundum 

 portiones opticas) dare diaplmnum ; corpora vero in- 



In their whole and undisturbed natural state, convey to the eye the 



state glass and water allow the rays impression of whiteness. &quot; In read- 



of light to pass through them and ing this, and many other instances 



refract only a little; consequently in the Nov. Org.&quot; says Herschel, 



they give us no sensation of white- (Disc. 198) &quot; one would almost 



ness : when the glass is pounded, it suppose (had it been written) that 



no longer allows of refraction as be- its author had taken them from 



fore ; and the rays of light being Newton s Optics.&quot; 

 reflected in great quantities in their 



