Remarks on Madeira, Isfc. 107 



also the arc of escapement. When the pendulum is truly in beat, 

 measure on this scale the arc of escapement. 



" 4th. Apply a weight to the pulley that will make the arc of 

 vibration from side to side three times the arc of escapement. 

 This is easily done by common lead shot in a bag, which when of 

 sufficient weight may be weighed, and the regular pulley weight 

 constructed. If the arc of escapement from side were one inch, 

 then the pulley weight ought to be so great that it may make the 

 index at the bottom move over three inches from side, and so in 

 proportion for any other arc of escapement. 



" 5th. Let the screw at the bottom of the rod have 40 turns 

 or threads to the inch, and the outer edge of the circle of the nut 

 be divided into 2S equal parts ; when the nut is moved one of 

 these divisions, it alters the going of the clock one second in 24 

 hours, very nearly. 



" With regard to the five things above mentioned, some peo- 

 ple will say. Let the crutch be short; that is, about 4 or 44^ inches 

 long, but no more. This is a very vague direction ; for it can 

 be proved not only by calculation, but by experiment, that the 

 shorter the crutch is, the more pullev-weight is required to give 

 the pendulum the requisite arc of vibration ; and this unfortu- 

 nately loads the pivots of the barrel or cylinder, that the pulley- 

 string goes round, occasioning a great deal of friction, and a con- 

 sequent irregularity from foulness, or thickening of the oil in cold 

 weather." 



XX. Remarks on Madeira, Climate of the Tropics, Trade-Winds, 

 Rio Janeiro, the Pola- Ice, ^c. Extracted from a Journal 

 kept by iouy Hammet, Esq. in a Foyagafrom England to 

 Rio Janeiro, Communicated by Dr. Pbaksun. 



MADEIRA. 



IVIr. Veitch, who has been British consul at Madeira these 

 many years, and is, besides, a wine-merchant of the first respec- 

 tability, gave us the following opinion concerning the compara- 

 tive virtues of Madeira and Teneriffe wines. It was simply, 

 " that bad Madeira is better than good Teneriffe." Dr. Thorn- 

 ton, however, who has written on the medicinal virtues of good 

 Teneriffe, differs in this respect, I am aware, widely with this ac- 

 compl! ';ed and hosi)itable gentleman. Mr. V. also asserted that 

 no Teneriffe wines are allowed to be imported to Madeira. Then, 

 since what has been long said concerning the consumjjtion in the 

 British dominions of wines under the denomination of Port, may 

 with cfpial propriety Ijc expressed of the con'^umption of wines 

 under the denomination of Madeira, the unjust substitution at 



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