304 THE FARMER AT HOME. 



It is not acted upon by acids, gives fire very freely with steel, and 

 when burnt, acquires a pure white color. This stone has not yet 

 been found in England ; but in the eastern parts, and in Germany, 

 there are large strata of it. It is much used by our artificers for set- 

 ting a fine edge on their tools, and is only used with oil, which by 

 degrees changes its color to a deep brown. 



OLIVE OIL. This is prepared from the fruit of the olive wiien 

 fully ripe, by pressing it gently ; it then yields the purest oil, but an 

 inferior kind is procured by heating the remainder, and squeezing the 

 fruit more strongly. Olive oil enters largely into the diet of many 

 nations, and is much used in medicine and pharmacy. When good, 

 it is of a pale yellow color, of a bland taste, and without smell ; when 

 long kept, it becomes rancid. When taken internally, it acts as a 

 mild laxative, but not many stomachs. can retain enough for this pur- 

 pose. It is sometimes given in pretty large doses for the expulsion of 

 worms, particularly some kinds of tsenia or tapeworm. And it may 

 also be given internally in small doses, with mucilage and other ad- 

 ditions, as an emulsion in cases of catarrh and sore throat. In cases 

 where certain poisons have been swallowed, large quantities of oil 

 are given to correct the acrimony of the substance swallowed. When 

 applied externally, it acts as an emolient, and forms a good medium 

 for frictions which are designed to promote absorption, and to discuss 

 indolent swellings. Warm oil rubbed on the belly, gives much reliei 

 in dysentery and other abdominal complaints ; and the same applica- 

 tion is one of the best means for dispersing the knots in the breasts 

 of childbed women, in the first days of their confinement. Olive oil 

 is an ingredient in many plasters and ointments. Combined with 

 hartshorn, it forms the volatile liniment, so useful as an external 

 stimulant. Some have said that anointing the body with oil prevents 

 a person from receiving the infection of the plague. 



OLIVE TREE. The olive tree, in all ages, has been greatly 

 celebrated, and held in peculiar estimation, as the bounteous gift of 

 heaven ; it was formerly exhibited in the religious ceremonies of the 

 Jews, and is still considered as emblematic of peace and plenty. 

 The utility of the fruit is very extensive. Pickled olives, which are 

 of two kinds, Spanish and French, are extremely grateful to many 

 Btomachs, and said to excite appetite and promote digestion ; they are 

 prepared from the green unripe fruit, which is repeatedly steeped in 

 water, to which some quicklime or alkaline salt is added, in order to 

 shorten the operation ; after this they are washed and preserved in a 

 pickle of common salt and water, to which an aromatic is sometimes 

 added. The principal consumption, however, of this fruit, is in the 

 preparation of the common salad oil, which is obtained by grinding 

 and pressing them when thoroughly ripe ; the finer and purer oil 

 issues first by gentle pressure, and the inferior sorts on heating what is 

 left, and pressing it more strongly. The bes v , olive oil is of a bright 



