876 PRACTICE OF AGRICULTURE. Part III. 



its tubers to be used as salep ; but the plant is very difficult of propagation from seed, 

 and can hardly be multiplied at all by the root, and though it may answer to collect the 

 tubers and prepare them, it is not likely it ever w^ill to attempt their culture. As the 

 plant is very abundant in some situations, it may be useful to know its preparation, 

 "which is thus described in Phil. Trans, vol. lix. 



5527. The btUb is to be washed in water, and the fine brown skin which covers it, is to be separated by 

 means of a small brush, or by dipping the root in hot water, and rubbing it with a coarse linen cloth. 

 When a sufficient number of bulbs is thus cleansed, they are to be spread on a tin plate, and placed in an 

 oven heated to the usual degree, where they are to remain six or ten minutes, in which time they will 

 have lost their milky whiteness, and acquired a transparency like horn, without any diminution of bulk. 

 Being arrived at this state, they are to be removed, in order to dry and harden in the air, which will 

 require several days to effect, or by using a gentle heat, they may be finished in a few hours. By another 

 process, the bulb is boiled in water, freed from the skin, and afterwards suspended in the air to dry ; it thus 

 gains the same appearance as the foreign salep, and docs not grow moist or mouldy in wet weather, which 

 those that have been barely dried by heat are liable to. Reduced into powder, they soften and dissolve 

 in boiling water into a kind of mucilage, which may be diluted for use with a large quantity of water or 

 milk. Thus prepared, they possess very nutritious virtues ; and if not the very same species as is brought 

 from Turkey and used for making salep, so nearly resembles it as to be little inferior. In Turkey the 

 different species of the orchis are said to be taken indifferently ; but in England, the orchis mascula is the 

 most common. (Gloucestershire Report, 377.) 



Chap. IX. 

 Of Marine Plants used in Agriculture. 



5528. All marine plants may he used as manure with great advantage, either in a recent 

 state or mixed with earth. But the most valuable vegetables which grow in or near salt 

 water, are those from which kelp or soda may be manufactured. The use of sea-weed, 

 as an article from which kelp might be manufactured, seems to have been practically 

 recognised in Scotland about the beginning of the eighteenth century. The great 

 demand for kelp in the manufacture of glass and soap at Newcastle, and of alum at 

 Whitby, seems to have introduced the making of this commodity upon the shores of the. 

 Forth) so early as about the year 1720. It began to be manufactured in the Orkney 

 Islands in the year 1723, but in the western shires of Scotland, the making of kelp was 

 not known for many years after this date. The great progress of the bleaching of linen 

 cloth in Ireland, first gave rise to the manufacture of kelp in that kingdom ; and from 

 Ireland it was transferred to the Hebrides about the middle of the eighteenth century. 

 On the shores of England the kelp plants are not abundant. 



5529. Of the different maiine plants which are eraployedfor the manufacture of kelp, the 

 Fucus vesiculosus {fg. 600 a), is considered by kelp makers as the most productive ; 

 and the kelp obtained is, in general, supposed to be of the best quality. 



5530. ThefudiJLS nodosus (6), is considered to afford a kelp of equal value to that of the abovfe species, 

 though perhaps it is not quite so productive. 



5531. The fucus serratus (c) or black weed, as it is commonly called, is neither so productive, nor is the 

 kelp procured from it so valuable as that obtained from the other two. This weed is seldom employed 

 alone for the manufacture of kelp; it is in general mixed with some of the other kinds. 



5532. The fucus digitatus (d), is said to afford a kelp inferior in quality to any of the others ; it forms 

 the principal part of the drift-weed. 



5533. The plants are cut in May, June, and July, and exposed to the air on the 



ground, till they be nearly dried, care being taken to prevent them, as much as possible, 



from being exposed to the rain. They are then burned, either in a pit dug in the sand or 



on the surface of the groimd, surrounded by loose stones, forming in both ways a i*ude sort 



of kiln, A peat fire is kindled on the ground, and the weed gradually added, till the 



