1814.] Scientific Intelligence. 237 



vitv. But does the specific gravity truly indicate and foretell the 

 strength of the ale or beer which the wort is to make? Are the 

 constituents of malt always dissolved in the same proportions to each 

 other? If not, I think little depeudance is to be placed on this 

 instrument." 



The saccharometer indicates correctly the specific gravity of the 

 wort before it begins to ferment. The value of the beer or ale 

 (supposing the process properly conducted) always depends upon 

 this strength. I do not mean to say that the price of the ale is 

 always proportional to the specific gravity of the wort ; I know very 

 well that the price is often regulated by fashion, and by the repu- 

 tation of the brewer; but I have made many experiments on the 

 subject, and think myself warranted in concluding from them that 

 the same substances are always taken up by water from good malt, 

 and that the value of the ale is proportional to the specific gravity 

 of the wort. 



It may be worth while to observe that the common saccharo- 

 meters do not give the true specific gravity of wort. I constructed 

 one about ten years ago which indicates the true specific gravity', 

 and the quantity of solid matter dissolved in the wort. It has long 

 been in common use in Scotland; thouglkl suppose it has never 

 made its way into England. 



XIII. Yeast. 



The same gentleman who put the two preceding queries lias 

 added the following: — 



" In the summer season it is very difficult, and often impossible, 

 for private families in the country to procure barm or yeast to bake 

 with. Pray is any method known of preserving it from the brewing 

 seasons, for any length of time, as two or three months? A 

 process for this would be of extreme utility." 



It has long been customary to dry yeast, and to carry it in sacks 

 from the Low Countries to Paris. It is sometimes sent in the same 

 • from IJiitain to the West Indies. When thus dried, it has a 

 dark colour, and a smell and taste not unlike cheese, or approach- 

 till Dearer to that of fermented gluten. 1 have kept it myself 

 several years in that state. When mixed with water, it acquires 

 the properties of fresh yeast ; but 1 did not find in my trials (which 

 were made in a distillery) that it went m> far as fresh yeast, and on 

 that account advised it to be discontinued. This dried yeast might 

 certainly be employed in private families when fresh yeast is not to 

 be had; and I take it for granted it can always be purchased in 

 London. 



XIV. A?males de Chi 



I have been requested by the editors oi ert the 



following notice in the Annals of Phil 



( 'himu •. that i-, Ai. ■ lion 



•tl memoir* concen ing try, and i 



m, particularly ; by MM. Guyl 



