Scientific Intelligence.— Botany. 185 



calculated that a man who is employed 8 hours a-day in turning 

 a crane or wheel, raises at an average rate, in every second of 

 time, a weight equal to 15 pounds troy, 39J inches high. 

 Supposing that the weight be 1751b. troy, the same quantity of 

 action is capable of raising his own weight to a lieight of about 

 33 inches ; so that, cceteris paribus, it is not the ninety-second 

 part of that which is exerted by the bird to sustain itself in the 

 air. If the man was capable of expending, in a space of time as 

 short as he pleased, the quantity of action which he exerts 

 ordinarily in the course of 8 hours, it appears that he might 

 sustain himself in the air, each day, for the space of 5 minutes. 



BOTAXY, HORTICULTURE, &C. 



15. Erica mediterranea found native in Ireland. — Mr James 

 Townsend Mackay, curator of the College Botanic Garden at 

 Dublin, having made a botanical excursion to the mountainous 

 district of Cunnemara, during the past autumn, was fortunate 

 enough to find Erica mediterranea " growing in prodigious 

 abundance." This is the most important addition which has of 

 late years been made to the Irish Flora. The plant has long 

 been cultivated in the gardens of the curious ; it withstands our 

 Scottish winters in the open border, with difficulty, and only in 

 sheltered situations, or near the sea-shore. It was regarded as 

 being indigenous only to the countries bordering on the Medi- 

 terranean, and to Portugal ; and certainly British botanists little 

 expected to be able to claim it as a native of the sister island. 



16. Hybrid Azaleas. — Mr Go wan at Highclerc, the seat of 

 the Earl of Caernarvon, has of late years raised many new sorts 

 of American azaleas, by means of cross impregnation, chiefly be- 

 tween the high-coloured and late-flowering varieties. For mo- 

 ther plants, the different fine varieties of A, coccinea, were 

 selected, major, minor, and rubescens, the anthers of which very 

 seldom produce pollen. The two former were dusted for seve- 

 ral successive mornings with the pollen of a late-flowering A. pon- 

 tica. Many pods swelled, and produced perfect seed. The pods 

 were gathered at the approach of winter, kept in a drawer for 

 some weeks, and sown in the beginning of January. Of these 

 about 400 seedlings were raised. The rubescens was impreg- 

 nated with the pollen of A. calendtila-cea, or Lee's triumphanSy 



