2 Wll.Di:, A loin i,- Wi/yii/s, Xcoii mid I Icliiiiii. 



Ill (.kIci lli;it tlic (:()i)iu;xi()n bctwci'ii the results of 

 the present paper uilh my fonnei- i-eseaiclu-s may be seen 

 without the tiouhle of i-ehiciices, I will recapitulate 

 several ol the |)oiiits previously discussed, to!.;ether with 

 tlie explaiiatoi)' tahlc-s of atomic weights. 



Since tlu; investi^-alion of the properties of silicon by 

 Ber/.eliiis, who r<-^arded silicic acid as a trioxide, much 

 discussion has arisen as to whether the atomic weii];ht of 

 silicon shoidd be .2 1 , 2S, or 3S- •md the formula- for its 

 oxide Si,,,0:„ SiO,, or Si,(),. 



'I'hrou^di the classical reseaiclu-s of Ke^nault tlu! 

 s|)C( ific heal of silicon was found to be O" 1 76 * The 

 detei miiiatioii was made with specimens of the metalloid 

 of (onsiderablc- si/.e and in a state of compactness aiul 

 pniit\' to receive a polish which loiined a perfect mirror. 

 The above innnber nmltiplied b\' .'S, the hi;_^hest atomic 

 weiidit assi!.;iie(l to Si, ;.;i\'es the product .|'9,t, while- the 

 law ol Didoni; and Petit re(|uires the value (y2^. 



in disiussin^^ the cause ol th<- anomalous atomic heat 

 of silicon, Ke^niault ixiinted out that in order that it 

 niiidit (-liter into the law of the specific lu-at of other 

 elements, it would be necessary to write the formula of 

 silicic acid Si,(),, ; it would then ii-sc-mble that of nitric, 

 phosphoric, and arsenic acid. The atomic weii^ht of 

 silicon woidil then be 35, and the product of this luimbcr 

 .111(1 tin- s|)ecific heat would be- nearly (y ?.'^, which ajijrees 

 with the analai^ous products tliat other sim|)le bodies j:[ivc. 

 \\y assiiMiin;.' to silicon a hi;.;hei' atomic W(-ii;ht and a 

 pol)l)asic character like that of phosphorus or nitrogen, 

 Keqiiault remarked that it is eas)' to explain the existence 

 of lh(- incat niimbei of silicates whi( h nature pr(-sents in 

 wcll-dclined and beautiful crystals, and to understand the 

 existence ol the natural h)(li() silicates. 



* Aiuhilvs ,/,■ Chciiii,' ,1 iU J'/i\<.u\/ii,\ Ionic S,v n>- -IS' (1S61V 



