VOL. XX.] PHILOSOPHICAL TRANSACTIONS. 231 



2. To presei've Fruit or Floivers the whole Year without spoiling. — Take salt- 

 petre 1 pound, bole ammoniac 2 pounds, common clean sand 3 pounds ; mix 

 all together; and observe this proportion in greater quantities. Then, in dry 

 weather, take fruit of any sort, which is not fully ripe, each with its stalk ; put 

 them, one by one, into an open glass, till it be full ; then cover it with 

 oiled cloth, close tied down. Then put each of these glasses 4 fingers deep 

 under ground in a dry cellar, and so as that quite round each glass, and both 

 above and below, there may remain two fingers thick of the said mixture. 

 Flowers may also be managed in the same manner. 



3. To make Fruit and Floiuers grojv in the /Fainter. — Take up trees by the 

 roots in the spring, just as they put forth their buds, preserving some of their 

 own earth about the roots. Set them standing upright in a cellar till Michael- 

 mas ; then fit them into vessels, with an addition of more earth, and bring 

 them into a stove, taking care to moisten the earth every morning with rain- 

 water, in a quart of which you must dissolve the size of a walnut of sal am- 

 moniac, and about Lent the fruit will appear. 



As to flowers, take good earthen pots, and therein sow the seeds at Michael- 

 mas, watering it in the same manner with the like water, and by Christmas you 

 will have flowers, as tulips, lilies, &c. This and the other may be performed 

 in a good warm kitchen ; and on such days as the sun shines you may set 

 them out for some hours. 



^ Contrivance for Measuring the Height of the Mercury in the Barometer, hy a 

 Circle on one of the JFeather Plates. By Mr. Wm. Derham. N° 237, P- 45. 



This circle, on one of the weather-plates, may be of any convenient dia- 

 meter. Divide this into 100 parts, which are to answer the 100 parts of an 

 inch. The index which points to these parts must be driven round by a small 

 wheel, like the dial-wheel of a watch. This wheel must be driven round by a 

 straight piece, like a small ruler, with teeth on one edge ; every inch of which 

 must contain just the same number of teeth as are in the dial-wheel before 

 mentioned ; so that by the thrusting up and down this toothed ruler, you 

 may at every inch turn round the index once. About the middle of this 

 toothed ruler a fine finger must be fixed, to point exactly to the height of 

 the mercury. And consequently by raising or depressing this finger to the 

 height of the mercury, you very exactly see, on the circle, the parts of an 

 inch which the mercury rises or falls in the tube. 



This description in words may perhaps be sufficient ; but to prevent obscurity 

 I have added a figure, see fig. 4, pi. 5, which represents the circle and toothed 

 ruler, without the interposition of the weather-plale ; that the contrivance may 



