156 Satfing Cast Iron with a Carpenters Saw. 



M. Vogcl has repealed M. Kirchoff 's experiment *, iisinc 

 2 parts of sulphuric acid to 100 of starch. After clarifying, 

 when cold, wiih charcoal and chalk, he evaporated nearly 

 to a svrup, set it by to cool that more of the sulphate of 

 lime might fall down, decanted off the clear liquid, and then 

 finished the evaporation. When he used a silver basin in 

 place of a tinned copper vessel (which is acted on by the 

 acid), the sugar was sweeter and whiter; but a leaden ves- 

 sel was found to answer every purpose. From a meaii of 

 several experiments, starch appears to yield its own weight 

 of syrup. The syrup mixed with yeast yielded carbonic 

 acid by fermentation, and by distillation a notable quan- 

 tity of alcohol. 



The fccula of potatoes, substituted for starch, gave also 

 a very saccharine gummy syrup : the syrup of starch al- 

 ways contains gum, the proportion of which varies accord- 

 ing to the time of boiling and the quantity of acid employed. 

 The gum, separated by means of alcohol, seemed in no re- 

 .^ptct to differ from gum arabic, except in not forming mu- 

 cous acid with nitric acid. 



Sugar of milk, which never ferments, acquired that pro- 

 perty when treated with sulphuric acid, and yielded alcohoK 



Dr. Tuthill has also converted the fecula of potatoes into 

 saccharine matter f. From impound of this fecula (the 

 produce of S| pounds of potatoes), treated with six pints 

 of distilled water and |th of an ounce of common sulphuric 

 acid, and clarified with charcoal and chalk, he obtained 

 1 1 pound of a crystalline mass resembling common brown 

 sugar mixed with a little treacle; and from one pound of 

 this mass he obtained by fermentation and distillation two 

 ounces and five eighths by measure of dilute alcohol, erf 

 such a gravity as (by calculation from Sir Charles Blagden's 

 experiments) made the produce equal to 14 drams by mea- 

 sure of proof spirit. 



SAWING CAST IRON WITH A CARPENTEr's SAW. 



M. Diifaud in a letter to M. d'Arcet, director of the iron- 

 works at Monlalaire, published in the eighty-second vo- 

 Jume o^ Ann. de Chim. announces that he has succeeded in 

 sawing cast iion with a carpenter's saw, and that all that is 

 necessary to ensure its being sawn as easily and in the same 

 space of time as dry wood, is that the iron be heated to & 

 cherry red. For heating the iron a furnace is preferable to a 

 forge fircj as the temperature is thus rendered more uniform 



* /l»}iaies dc Cliimie, vol. Ixxxii. 



t- Nich'jljoii's Journal, vol, xxiiii. p. S19. 



throughout 



