150 



themselves to the Vegetable World. Such men were Ingen- 

 houz. Van Helmont, Priestley, Sennebier, Schraedcr, Saussure, 

 &c. To them we are indebted for the most luminous researches 

 into the food of plants, the influence of air, of heat, of light 

 and of soils. Previous to their researches the immense impor- 

 tance of the leaves of Plants was unknown. Cultivators were 

 unaware that by removing one of them they were proportionably 

 removing the means of breathing and of nourishment from the 

 parent plant; and mankind in general were ignorant that it is 

 by the Gas which Plants throw oflf, that the animal Creation is 

 alone enabled to breathe. 



The scientific institutions of previous years, which had merely 

 existed, now were in a state of vigorous exertion. The Botanic 

 Garden of Chelsea, was especially distinguished under its Cura- 

 tor Philip Miller. This Garden, as previously stated, was founded 

 in 1673, though the inscription over the gateway is dated 1686, 

 until which year it was not effectually arranged. It was 

 strengthened and rendered permanent by Sir Hans Sloane, in 

 1721. He having purchased the manor, gave the scite, which 

 is a freehold of four Acres, to the Company on the conditions 

 that they should pay £5 per annum for it, and that the de- 

 monstrator of the Company, in their name, should deliver an- 

 nually fifty new species of Plants to the Royal Society, until 

 the number amounted to 2,000. This presentation of Plants 

 commenced in 1722, and continued until 1773, at which time 

 they had presented, 2550 species. 



If old Botanical institutions improved, so also new ones 

 were formed. The Kew Gardens, were commenced in 1760, 

 by the Princess dowager of Wales, mother of George the HI. 

 The exotick department was established chiefly through the 

 influence of the Marquis of Bute, a great patron of Gardening. 

 It was placed under the care of Mr. W. Aiton, and it has since 

 become one of the most celebrated Botanical Institutions in 

 the world. 



