On the Coji of lllumtaation h^. different Kinds a/ Candleti,- xS? 



9. The property difcovered byBayen Is therefore analogous to the fulminating property 

 of the orate and the argentate of ammonia j but it is not perceptible in the other metallic 

 oxides and precipitates. Hence the oxtgen in the Jatter muft. neceffarily contain a lefs 

 portjpn of caloric. 



, ,10. The properties which depend upon oxidation vary therefore in each metal, on ac- 

 count of the proportions of oxigen ; and thofe which depct^d on the ftate of concentration 

 poffefled by oxigen, conftitute the leading caufe of thofe phsenomcria which arife from the 

 changes of combination in elaftic fubftances. {^Inquiries, Art. XIV. Nos. I2 and 15,.) 



(To be continued.) 



VIII. 



Experiments and Obfervat'mis on various Kinds of Candles, made of Wax, Tallow, Spermaceti^ 

 andoffuch as are manufaSlured of a Mixture of thefe Subflances ; as well with Regard t9 

 Cheapnefs as to the ^antity of Light they afford. By Sig. Fr. HermSTAEDT, Profeffor and 

 Member of the Royal College of Phyftciaiis at Berlin*. 



T. 



HE illumination of apartments is an article of the firft neceffity for every clafs of 

 people, and the means by which it is produced are fo likely to advance in their price, that 

 this illumination continues to be an object of confiderable importance, for every family in 

 houfekeeping, whether numerous or moderate. But as it is impoffible to obviate this ne- 

 ceffity for lighting our apartments, it becomes the duty of every one to be attentive to the 

 profpefts of ceconomy in this refpeft : fince the faving, though fmall with regard to a fingle 

 candle, may neverthelefs in time amount to a fum by no means contemptible in houfe- 

 keeping upon a larger fcale ; more efpecially, when the elegant enjoyments of life demand 

 a brighter light, than is neceffary for the mere purpofes of domeftic utility. 



The experiments which I lately had an opportunity of making during the official exa- 

 mination of various forts of tallow candles, with regard to ceconomy in their confumption, 

 ti8 well as to the quantity of light afforded by their combuftion, afforded refults, which 

 appeared defcrving of attention, and were fufficient to induce me to make a new fet of 

 experiments, with candles made of mixed ingredients, in order to compare them with the 

 former. Thefe, likewife, furnifhed refults by no means iininterefting, and afford con- 

 clufions of equal utility. Thefe reafons have induced me to puljlifli my obfervations for 

 further examination ; and even fhouM my remarks and obfervations appear to fome readers 

 of very fubordinate importance, yet I might requeft them to confider, that even fadts of 

 little moment have frequently afforded a foundation to more difcoverles of. greater mag- 

 nitude. 



* Tianflated from the German in Scherer^s Allgemeinen Journal dtr Chemle, Vol. IV, pjge 40. 



Bb2 FirJI, 



