Dr Graham''s Description of New or Rare Plants. 173 



stj^uare inches, which sustained an upward pressure from the column of water 

 in the pipe P of 1853 pounds, and the product of filtration was at the rate of 

 half a gallon per minute ; and since the altitude of the pipe into the area of 

 the stone proportions the quantity, it is a simple question to find what area 

 and altitude together would produce 10, 20, or 100 gallons of filtered water 

 every minute. To produce such effects, a number of stones must be used in 

 the same machine. I believe it yet remains to be proved whether filtered 

 water preserves as well at sea as that which is not filtered. I conceive it will 

 be found to keep equally' well, or perhaps better, as filtration removes all ani- 

 mal and vegetable matter which it holds in suspension, the former frequently 

 both in a live and j)utrid state, a circumstance which cannot reasonably have 

 any tendency to preserve water. Should experience prove that my hypothe- 

 ses are correct, I would propose, for the benefit of the public in general, aind 

 the shipping interest, that a machine on a large scale should be erected at 

 every sea-port, where ships are in the practice of taking water, which should 

 be sent at once filtered to sea. 



Description of several Nezo or Rare Plants which have floxvered 

 in the neighbourhood of Edinburgh^ and chiefly in the Royal 

 Botanic Garden, during the last three months. 



10th Dec. 1828. 



Begonia insignis. 



B. insignis ; subherbacea ; caule erccto, ramoso, nodoso, glabro ; fcliis 

 longe petiolatis, in8e{[ualiter cordatis, acumiiiatis, obsolete lobatis, du- 

 plicate serrato-ciliatis, supra sparse strigosis, subtus subrubris, gla- 

 bris ; stipulis lineari-triangularibus, acuminatis, integerrimis ; pedun- 

 culis terminalibus, nutantibus, bis terve dichotomis, multifloris ; cap- 

 sulae ala maxima acuta, reliquis obtusis. 

 Description — Stem erect, subherbaceous, entirely free from hairs, but 

 rough and brown, swollen at the joints. Branches erect, smooth, shining, 

 subpellucid, reddish, and with a few white oblong spots. Leaves alter- 

 nate, on smooth shining petioles, which are nearly round, and half their 

 ' own length, unequally cordate, acuminate, slightly concave, pale green, 

 and sparingly strigose above, paler green, or red, and always naked be- 

 low, obscurely lobed, and doubly serrato-ciliate, crisped, especially when 

 young. StipulcB linear-triangular, narrow, acuminate, entire in the 

 edge, pellucid, and nearly colourless, submarcescent. Peduncles ter- 

 minal, twice or thrice dichotomous, nodding. Bractece cordato-ovate, 

 keeled, reflected at the sides, a pair bein<; placed at each bifurcation of 

 the peduncle, caducous. Flowers monoecious, large, rose-coloured, very 

 handsome. Male ; one standing in each bifurcation, on a peduncle 

 above two inches long, and having in the ultimate division a female 

 flower on each side, unless, as is not unfrequent, one of the females 

 proves abortive ; corolla tetrapetalous, two of the petals large (Jths of 

 an inch in either diameter), cordato-subrotund, and slightly pointed, 

 the two others nearly as long, but much narrower, spathulate ; sta- 

 mens about 40, yellow, monadelphous ; anthers bilobular, wedge-shaped, 

 somewhat flattened ; pollen yellow. Female ; corolla smaller than in the 

 male, generally of five obovato, somewhat irregular, imequal petals, oc- 

 casionally only four ; style greenish-yellow, stout, 3-parted, diverging, en- 



