S P E 



Great experience and fagacity, with perhaps a peculiar 

 talent, are requifite to form a good judge of fpecific cha- 

 rafters. To convey a prccife idea of them to others, re- 

 quires a clearnefs of dcfmition, and a command of lan- 

 guage, granted to very few. Linnieus, with good reafon, 

 limits filch characters to a certain number of words, hardly 

 exceeding twelve. However narrow thefe bounds may ap- 

 pear, we believe them to be in general, if not always, fuf- 

 ficient ; and every pcrfon will perceive that the confequence 

 of their tranfgreffion is ufually feeblenefs, if not confnfion, 

 of definition. It mull always be remembered that fpecific 

 charafters are differences, not Jeferiptions. Hence a fpecific 

 charafter for a lolitary fpecies of any genus, is an abfurd- 

 ity. It cannot contrail fuch a fpecies with what are un- 

 known, or perhaps do not exill. A fhort defcription may 

 be very commodious or fatisfaftory to give an idea of the 

 plant, efpecially if the author miftrufts his genus or its defi- 

 nition ; but if the genus b« good, the very charadcrs which 

 he will feleft to delineate the habit, or prominent peculiari- 

 ties, of the only known fpecies, will, moft likely, be com- 

 mon to any new ones that may fubfequently be difcovered. 



Linnaeus remarks, that the deteftion of genuine fpecific 

 dillinftions is the fummit of botanical (kill. To which we 

 may add, that thofe have moft excelled in this department 

 who have caught the greatell Ihare of the genius of this 

 great man, whofe definitions come as near to perfeftion as 

 art can come to nature. 



SPECIFIC, in Philofophy, that which is proper and pe- 

 culiar to any thing ; or that charaClerizes it, and diftin- 

 guifhes it from every other thing. See Proper, &c. 



Thus, the attrafting of iron is fpecific to the load-done, 

 or is a fpecific property of the load-ftone. A juft definition 

 Ihould contain the fpecific notion of the thing defined, or 

 that which fpecifies and dillinguifties it from every thing 

 elfe. 



Specific, in Medk'mi, fuch articles in the materia me- 

 dica as have the fpecial power of curing particular difeafes, 

 in all perfons, and under all circumftances, without demand- 

 ing any attention to particular indications. In other words, 

 2. fpecific is a certain antidote againft a given difeafe. Not- 

 withftanding, however, the multitude of fuch fpecifies, 

 which are every day announced by boalUng quacks, and 

 teftified to by all ranks of people, who are their dupes, it 

 unfortunately happens that no fuch remedies exift. As 

 found fcience has extended, all thefe vaunted fpecifies have 

 fucceflively been banifhcd from the confidence of men of 

 fenfe and information ; and almoft every remedy has fome 

 obvious aftion upon the animal fyftem, fo that the principles 

 of its operation in particular difeafes may be pointed out. 

 Peruvian bark was formerly fuppofed to be a fpecific for in- 

 termittents and agues ; but it is now known to fail in many 

 cafes, and not to be more efficacious than other medicines of 

 a tonic power, fuch as arfenic, and fome combinations of 

 bitters with aromatics, which are popularly ufed in agucifii 

 countries. The two medicines which approach the neareft 

 in their qualities to the charafter of fpecifies, are mercury, as 

 the antidote to the venereal poifon, d.x\A fulphur, to that of 

 the itch. Indeed it is only in cales of the aftual exiftence 

 of a morbid poifon, that any dillinft antidote can poflibly 

 exift. But even with refpedt to thefe two medicines, it is 

 well afcertaiiicd that there are cafes of difeafe, fo accurately 

 refemblmg lues venerea, as not to be diftinguiftiable by the 

 moll acute and experienced eye, which neverthelefs recover 

 without the aid of mercury (fee Mr. Abernethy's " Ac- 

 count of Difeafes which ftrikingly refemble the Venereal 

 Difeafe") : and we know that the powers of fulphur in 

 curing the itch are confiderably augmented by the addition 



See Specific Gra- 

 Mr. Robertfon, in 



S P E 



of other fubftances, fuch as hellebore, muriate of ammonia, 



the white oxyd of mercury, &c. All other inftances of 



pretended fpecifies are impofitions. 



Specific Gravity, in Hydrofiatiei. 



VITY. 



Specific Gravity of Living Men. 

 order to determine the fpecific gravity of men, prepared a 

 ciftern, 78 inches long, 30 inches wide, and 30 inches deep ; 

 and having procured 10 men for his purpofe, the height of 

 each was taken, ar(d his weight ; and afterwards thev 

 plunged fucceflively into the ciftern. A ruler, graduated 

 to inches and decimal parts of an inch, was fixed to one end 

 of the ciftern, and the height of the water noted before each 

 man went in, and to what height it rofe when he immerfed 

 himfelf under its furface. 



The following table contains the feveral refults of his ex- 

 periments. 



One of the reafons, Mr. Robertfon fays, that induced 

 him to make thefe experiments, was a defire of knowing 

 what quantity of fir or oak-timber would be fufBcient to 

 keep a man afloat in river or fea-water, thinking that molt 

 men were fpeeifically heavier than river or common frelh 

 water ; but the contrary appears from the trials above re- 

 cited : for, excepting the firlt and laft, every man was 

 lighter than his equal bulk of frefh water, and much more fo 

 than his equal bulk of fea-water : confequently, if perfons 

 v^'ho fall into water had prefence of mind enough to avoid 

 the fright ufual on fuch accidents, many might be preferved 

 from drowning ; and 3 piece of wood, not larger than an 

 oar, would buoy a man partly above water as long as he had 

 fpirits to keep his hold. Phil. Tranf. vol. 1. art. 5. 

 Specific Gravity of Metals. See the feveral metals. 

 Specific Heat. See Heat. 



Specific Names, m Natural Hi/lory, are thofe epithets 

 compofed each of one or more terms, and placed after the 

 generical name, in the denomination of any fpecies of plant, 

 animal, or mineral, expreffing thofe charaAers by which it 

 differs from all the other fpecies of that genus. 



The more accurate of the modern naturalilts have, in their 

 feveral provinces, fct about the reformation of the fpecific 

 names of things. They firft obferve, that many of the 

 fpecific names of the ancients no way anfvvered the intent of 

 their formation, but expreffed the more trivial diftinftions, 

 or accidents, while they omitted the realities, and more 

 effential grounds of diftinttion. On this foundation the 

 critical writers of our times diftmguifh the old fpecific 

 names into the genuine or true, and the fpurious or falle 

 ones. 



The genuine names are thofe which exprefs thofe charac- 

 ters, 



