rennial; grows in moist shady hedges, and meadows; where it flowers in the mouth of July. This species is remarkable for its beauty, and is an ornament to ditch-banks and hedges: it is rejected by cattle.—Prof. Pallas observes, that the panicles of the Small Reed, before the flower expands, impart a beautiful bright-green colour to wool, when boiled, with the addition of alum.
Reed, the Mace: SeeCat's-tail.
Refining: See Distilling.
Regimen, of Invalids: See Debility.
RENNET, or Runnet, properly denotes the coagulated milky substance which is found in the stomachs of calves, that have received no other nourishment than the maternal milk. It is, however, generally applied to signify the stomach itself, which possesses equal properties.
The rennet commonly employed, consists of the inner membrane of a calf's stomach, which is cleaned, salted, and suspended in paper bags. Previously to its use, the salt is extracted by washing the rennet, which is soaked in a little water during the night; and, in the morning, the infusion is poured into the milk, with a view to coagulate this fluid. As the preparation now stated, greatly contributes to the superior quality of English cheese, the proper management of it ought to be conducted with the strictest attention to cleanliness: the reader will, therefore, find a receipt for making an excellent rennet, in the article Cheese, vol. i. p. 497.
It sometimes happens, however, that no rennet, sufficiently good for curdling milk, can be procured: hence various plants have been advantageously substituted, and found to answer the same purpose. The principal of these are the flowers of the Cheese-rennet, or Yellow Ladies Bed-straw (Galium verum L.) used in England; and the Cardoon (Cynara cardunculus L.) in Spain. A strong infusion is made of the down of the latter vegetable in the evening; and, on the succeeding morning, half a pint is poured among fourteen gallons of new milk, which is thus effectually coagulated, and in consequence produces a delicious cheese.
RESERVOIR, a place artificially constructed for the collection and retention of water, in order that it may be conveyed to distant places, by means of pipes.
Reservoirs are at present chiefly employed for the supply of fountains, jets d'eau, and similar volumes of water. Although such contrivances heighten the picturesque scenery of plantations, yet we conceive that they might be rendered productive of greater advantage to agriculturists, by forming them in certain situations, for the reception of flood-waters, and the prevention of many accidents, that happen in consequence of land-floods. Where the soil is naturally porous, and the strata, lying beneath, are so open as to absorb the rain-water during its descent, no floods will easily occur; because the fissures or pores operate as regulators for conducting the streams; and the discharge becomes so equal, that the humidity remains nearly in the same state throughout the year. In clay, and similar retentive lands, however, a very small portion of water is absorbed, and such large quantities speedily glide off the sur-
