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carbonate of lime has been found to occur in this manner are the 

 common elm, American nettle tree (Celtis), common sycamore, 

 white poplar and silver birch. Carbonate of lime may also be 

 found in the cavities in wood known as " windshakes." Mr. 

 Valentine Ball, of the Geological Survey, found instances in India 

 where deposits of limestone actually alternated with the ordinary 

 rings of wood growth in the trunks of trees. Masses of such 

 deposits of irregular shape, seven inches long by two broad, were 

 found in trees six feet above the ground. 



Perhaps the most interesting of all occurrences of lime in 

 plants are pearls in coco-nuts. These were first described by 

 Rumphius from the East Indies more than two centuries and a 

 half ago. He not only drew up a careful description of them, 

 with illustrations, but even sent a specimen coco-nut pearl in 1683 

 to the Grand Duke of Tuscany, who had it mounted in a ring. 

 For a long period after this coco-nut pearls were only known 

 locally to the Rajahs and Mandarins, who attributed all manner 

 of virtues to these rare products. In 1887, Professor Hickson, 

 F.R.S., now of the Victoria University of Manchester, announced 

 in " Nature " his discovery of coco-nut pearls while exploring the 

 Celebes. One of the specimens brought home by him is now in 

 the Museum at Kew. I have been fortunate enough to see and 

 examine two others. One in the possession of Mr. Streeter, 

 formerly of Bond Street ; this was finely engraved with Arabic 

 characters. The other was the property of a lady living at Kew 

 whose father had brought it from Singapore. An analysis of one 

 of the specimens obtained by Professor Hickson proved it to be 

 pure carbonate of lime and almost identical with that produced by 

 the pearl oyster. Coco-nut pearls are either globular or egg-shape. 

 The colour is pure milk-white. They are somewhat deficient in 

 lustre as compared with ordinary pearls and rather harder. So 

 far coco-nut pearls have only been found, or at least reported, 

 from the Eastern tropics. 



As naturally might be expected from what is stated above, 

 carbonate of lime is found in the ash of most plants. Ash from 

 the branches and leaves of the common yew growing in different 

 soils have been analysed with the following results : Ash from 

 yews growing on metamorphic rocks, such as serpentine, con- 

 tained 16 per cent, of lime, on gneiss 30.6 per cent., and on lime- 

 stone 36 per cent. It will be noticed that the ash from trees grow- 

 ing on limestone yielded more than double the amount of car- 

 bonate of lime compared with those growing on serpentine soils. 

 This may afford a clue to the presence of the large deposits of 

 lime found in the trees referred to above. It is not improbable 

 that where soils are heavily charged with lime the roots take up 

 a larger proportion of it, which is afterwards deposited in the 

 tissues. Possibly the formation of pearls in coco-nuts may be due 

 to similar circumstances. The largest proportion of lime found 

 in the ash of any vegetable growth is met with in the stone-worts 

 (Chara). According to Kerner this amounts to 54.8 per cent. 



