40 Mr, C. Holthouse on Increasing the Light 



experiments being kept under slight pressure and at an 

 equable temperature of near 70° Fahr. 



Mixtures of this kind conducted through the vinous fer- 

 mentation in silver and china vessels always afforded a larger 

 quantity of ashes after evaporation and calcination than those 

 made in glass apparatus. But upon the proportionate in- 

 crease by this process in any experiment, we can speak at the 

 outset with as little certainty as upon the height to which 

 any plant will grow when the seed is first planted. One of 

 the features which I have always found to accompany their 

 formation is an increase in colour, which colour again disap- 

 pears when they undergo decomposition by the putrefactive 

 fermentation and have ammonia as a product. 



I have found the quantity to vary with almost every cir- 

 cumstance, even in experiments made with the same mixture, 

 from little or no increase to that of twenty times the weight 

 of those included in the sugar experimented upon. My ex- 

 periments made with solutions containing about ten per cent, 

 of their weight of sugar (the strength employed by Mr. Smith) 

 rarely gave more than an appreciable increase upon the ori- 

 ginal quantity, except when the fermentation was conducted 

 very quickly. 



The ashes were obtained by evaporating and burning over 

 a spirit-lamp without the addition of any foreign agent, the 

 materials being in an open platinum vessel. Their quantity 

 was determined by weight as a whole, with the addition of 

 their power of neutralizing acids as regards their alkaline 

 property. 



Walworth Road, April 14th, 1840. 



VII J. On Increasing the Light of a common Argand Lamp, 

 By C. Holthouse, Esq.* 



To the Editors of the Philosophical Magazine and Journal, 

 Gentlemen, 



11TAVING seen in the Number of your Magazine of March 

 •*-•*• last, a letter from Sir J. Herschel, "On a simple mode 

 of obtaining from a common Argand Oil Lamp a greatly in- 

 creased quantity of Light," I take the liberty of sending you 

 a few observations of my own on the same subject; they are 

 mostly corroborative of what has been advanced by the di- 

 stinguished philosopher before alluded to, and if you think 

 them worth insertion they are very much at your service. 



* Communicated by the Author. 



