AMM 



AMM 



branches the flowers are produced in 

 small umbels; these are of a fine blue co- 

 lour, us arc :.isn the upper part of the 

 branches, and the learetlnvnediatelj un- 

 der the umbel; so that though the flowers 

 un- small, ye', from their colour, with 

 that of the upper part of the stalks, the 

 plants make a pretty appearance during 

 their continuance in flower. 



AM! A, in natural history, a genus of 

 fishes of the order Alxioniiuales. (icue- 

 ric character: head bony, naked, rough, 

 with visible sutures. Teeth, both in juws 

 and palate, close-set, sharp, numerous. 

 Cirri or beards two, near the nostrils. 

 Gill-membrane twelve-rayed: bod 

 ly. There is a single species, Calva, a 

 small fresh water fish, inhabiting some 

 parts of Carolina,of which the tail is round- 

 ed, and with a black spot ; it is seldom 

 eaten. 



\\liABLE, or amicable numbers, such 

 as are mutually equal to the sum of one 

 another's aliquot parts, as the numbers 

 284 and 220. 



\ an Schouten was the first who gave 

 this name to such numbers, of which there 

 are but very few at least to be set down 

 and manageable by us. For 284 and 220 

 are the two least. The aliquot parts of 

 220 are 1, 2, 4, 5, 10, 11, 20, 22, 44, 55, 110, 

 and the sum of these- is equal 284. The 

 aliquot parts of 284 are 1, 2, 4, 71, 142, 

 and the sum of these is '220. The second 

 pair of applicable numbers are 17296 and 

 18416. The third pair are 9365584 and 

 9437056. 



AMI \NTIIl S. See ASBESTOS. 

 AMICUS /-i/r/.r, iii law, if a judge be 

 doubtful or mis'aken. in a matter of law, 

 aider may inform the court as //'- 

 eiis ci trice. 



AMMANNIA, named by lioustoun in 

 honour of J. Amman, in botany, a genus 

 of the Tetrandria Monogynia ci 

 order. Its characters are, that the calyx 

 is a perianth'umi, bell-shaped, oblong, 

 erect, with eight streaks and folds, quad- 

 rangular, eight-toothed, teeth alternate, 

 bent in, and permanent ; corolla none, or 

 four-petalled, petals vertically ovate, 

 spreading, inserted into the calyx ; the 

 stamina have filaments, (four or eight) 

 bristly, the length of the calyx into which 

 they are inserted, ant hers twin ; the pistil, 

 lum is a germ subovate, large and supe- 

 rior, style simple, ver\ short, ami 

 headed ; the pericarpium is a roundish, 

 four-celled capsule (bury i covered with 

 the calyx; the seeds are numerous and 

 small. 



\ M MI, hichrif)':; T;W</. iii b'i:.nv. ;\ dis- 



tinct jBfenus of umbelliferous plants, be- 



: utaii'lria \t.y, -.a class 

 i-us; the flower of which il 

 c, mis, and composed of hcart-lilv \> 

 and its fruit is a small round ish and stri- 

 ated capsule, containing two striated 

 seeds, convex on one side, and plane on 

 tin- other. There are four species. 



AMMODYTES, in natural history, the 

 launci; a genus of fishes, of the order 

 Apodes : head compressed, narrower than 

 the body : upper lip doubled: lower jaw 

 narrow, pointed: teeth small and sharp. 

 Gill-membrane seven-rayed: body long, 

 roundish, with very small scales : tail dis- 

 tinct. A. tobianus, or sand launce, so 

 named from its shape. It inhabits the 

 northern seas; and is from 9 to 12 inches 

 long. It buries itself on the recess of the 

 tides a foot deep in the sand, and in fine 

 weather rolls itself up and lifts its nose 

 just above the sand; it is the prey of 

 other rapacious fish ; the flesh is tolerably 

 good, but it is used in most cases as baits. 

 The launce lives on worms, water-insects, 

 and small fishes, and even occasionally on 

 those of its own species. The mackarel 

 is very partial to this fish as its own 

 food. The launce spawns in May, depo- 

 siting its eggs in the mud, near the edges 

 of the r 



A M MOM A, in chemistry. Volatile al- 

 kali, in its purest form, subsists in a state 

 of gas, and was thought, till the late expe- 

 riments of Mr. Davy, to be composed of 

 a/.ote and hydrogen. It may be obtained 

 inthefollowingmanner: put into a retort 

 a mixture of three parts of quick-lime and 

 one part of sal ammoniac in powder. 

 Plunge the beak of the retort below the 

 mouth of a glass jar filled with mercury, 

 and standing inverted in a busin of mer- 

 cury. Ap|il\ the heat of a lamp to the 

 retort : a gas comes over, which d^ 

 the mercury and nils the jar. This gas 

 is ammonia. It was known by the name 

 of volatile alkali; it was also called harts- 

 horn, because it was often obtained b\ 

 distilling the horn of the hart ; spirit 01' 

 urine, because it maybe obtained by the 

 same process from urine ; and spirit ot 

 sal ammoniac, because it may be obtained 

 from that salt. Dr. ISlack first pointed ou 

 the difference between ammonia and car- 

 bonate of ammonia, orammonia combined 

 with carbonic acid; and Dr. I'riestlcy dis 

 covered the method of obtaining it, in : 

 state of purity, by the process already 

 described. Ammonia, in the s'atc of gas, 

 is transparent and co!o'irles> like air; it> 

 - acrid and caustic like that of tin- 

 fixed alkalies but not nenrlv so strong, not- 



