C E R 



v/hich he gave the name of ochroUa. (See Ochroite.) 

 About the fame time this mineral was examined with more 

 attention by Hifinger and Berzelius, who gave it the name 

 of cerit, and detedled in it a pecuhar fubftance, which they 

 confidered as a metaUic oxyd, to which they gave the name 

 of Cerium, from the planet Ceres, then lately difcovered by 

 Piazzi. They did not fucceed in reducing this oxyd; nor 

 was Gahn, who made the experiment fome time afterwards, 

 more fuccefsful. Vauquelin, however, who had formerly 

 examined the mineral, turned his attention to the fubjetl a 

 fecond time, and he fucceeded in reducing it fo far as to 

 fliew that its baiis is a metal. 



In 1 8 14 a new fet of experiments was made upon it by 

 Laugier. He appears to have reduced it to the metallic 

 ftate, but combined with carbon. Oxalic acid, according to 

 Laugier, feparates the whole of the oxyd of cerium from 

 iron. The affertion of this chemift, however, tbat its oxyd 

 is not volatile, has been denied by Dr. Thomfon. 



To procure the oxyd of cerium in a ftate of purity, the 

 Swedifh chemifts employed the following method. The 

 mineral was reduced to a fine powder, and digefted in nitric 

 acid till every thing foluble was taken up. The folution 

 was then evaporated to drynefs, and the refidue diflblved in 

 water. Into this folution ammonia was poured, till every 

 thing precipitable by its means was thrown down. The 

 precipitate being well wafhed, was rediflblved in nitric acid, 

 the acid neutralized, and then tartrate of potafti added to the 

 folution. The precipitate thus formed was then heated to 

 rediiefs, well wafhed with vinegar, and dried, and was con- 

 fidered as pure oxyd of cerium. 



The oxyd of cerium, when firft prepared, is white ; but 

 when it has been heated it becomes reddifh-brown. Formed 

 into a pafte with oil, and heated in a charcoal crucible, it 

 lofes weight : when urged by a ftrong fire on charcoal, it 

 does not melt but continues in powder. It exhibits, how- 

 ever, brilliant particles, which were proved to be of a metallic 

 nature. 



According to Vauquelin and Hifinger, cerium combines 

 with two proportions of oxygen. The protoxyd is white : 

 the peroxyd reddifh-brown. The peroxyd contains i^ 

 times as much oxygen as the protoxyd. The protoxyd, 

 according to Hifinger, is compofed of 



Cerium - 1 00 



Oxygen - 17.41 



The peroxyd of Cerium - 100 



Oxygen - 26.115 



From Hifinger's experiments, it appears that the equi- 

 valent number for the protoxyd of cerium is 67.5, and of 

 the metal 57.5. But if with Dr. Thomfon we fuppofe the 

 peroxyd to be a compound of two atoms of cerium and 

 three of oxygen, the weight of the atom of peroxyd will 

 be 145. 



No compound of this metal with hydrogen, azote, chlorine, 

 nor fluorine is known. The carburet formed by Laugier 

 was a black matter, which took fire fpontaneoufly when 

 expofed to the air. The phofphuret, which appears to 

 have been formed in one inftance by Hifinger and Berzelius, 

 was a hard, brown, tenacious fubilance, which fhone in the 

 dark, and took fire when heated. 



Hydiofulphuret of ammonia throws down cerium at firft 

 of a brown colour, but it becomes.deep green if the re-agent be 

 added in larger quantity. When dry, the hydrofulphuret 

 formed is a bright green, and burns when heated, leaving a 

 yellow oxyd of cerium. The colour of the precipitate 

 varies, however, according to the ftate of oxydation of the 

 cerium held in folution. 



C E R 



No alloy of cerium is known, except one with iron, 

 obtained by VauqueHn ; this was white, brittle, and diftolvcd 

 with great difficulty in nitro-muriatic acid. 



Salts of Cerium. Nitrate of Cerium. — Nitric acid unites with 

 both the oxyds of cerium ; with the white oxyd it combines 

 moft readily. The folution is colourlefs, cryftallizes with 

 difficulty, retains an excefs of acid, and has a fvveet aufterc 

 tafte. The red oxyd diflblves with difficulty in cold nitric 

 acid, but the folution may be readily effefted by heat. The 

 folution is yellow, and if an excefs of acid be prefent, it 

 yields fmall white dehquefcent cryftals. Both the nitrates 

 are foluble in alcohol, and are decompofed by heat. 



Muriate of Cerium. — This fait exifts in the form of fmall 

 four-fided prii'matic cryftals of a yellowilh-white colour. 

 They are foluble in alcohol, and deliquefce on expofure to the 

 air. When expofed to heat they are decompofed. 



Sulphate of Cerium. — Sulphuric acid dilTolves the red 

 oxyd of cerium with difficulty. The folution when obtained 

 is of an orange-colour, and yields by evaporation fmall 

 oftahedral and needle-formed cryftals of perfulphate of 

 cerium. Their colour is partly lemon -colour and partly 

 orange. This fait is not foluble in water without excefs of 

 acid. When expofed to the air, the cryftals foon affume the 

 form of a yellow powder. Sulphuric acid combines readily 

 with the white oxyd of cerium, efpecially when in the 

 ftate of carbonate. The folution is colourlefs, and readily 

 cryftallizes. There is a triple fulphate of potafti and 

 cerium. 



Phofphate of Cerium. — This is a white powder infoiuble 

 in water, but foluble in the nitric and muriatic acids. 



Arfcniate of Cerium. — This fait is infoiuble. There is a 

 foluble fuperarfeniate which does not cryftallize. 



Acetate of Cerium. — This fait exifts in the form of finull 

 granulated cryftals, readily foluble in water, but fparingly 

 foluble in alcohol, and not altered by expofure to the air. 



Oxalate of Cerium. — Oxahc acid and oxalate of ammonia 

 precipitate cerium from its folution. The precipitate with 

 the peroxyd is red, with the protoxyd white. It is not 

 foluble in excefs of acid, but readily in ammonia. 



Tartrate of Cerium. — The tartrate of potafti throws down 

 cerium from its folutions in the form of a white infoiuble 

 tartrate. This tartrate, however, is foluble in nitric, 

 muriatic, and fulphuric acids, and alfo in pure alkalies. 



Citrate of Cerium. — The citrate of cerium is infoiuble, 

 without an excefs of acid, when it is readily foluble. The 

 folution does not cryftallize. The other falts of tliis metal 

 are unknown, or devoid of intereft. With refpeft to thefe 

 falts in general, it may be obferved, that they are either of 

 a white or yellow colour, according to the ftate of oxydation 

 of the metal, and their folutions have a fweetifti tafte. The 

 hydrofulphuret of potafli, pruffiate of potadi, and oxalate of 

 ammonia, produce in them white precipitates ; wliile the 

 gallic acid and infufion of galls occafion no precipitate, 

 when added to folutions of their falts. 



Cerium. See Mineralogy, Addenda. 



CERNE, or Cerne-Abbas, 1. 36, add— In 181 1 the 

 parilh contained 145 houfes, and 795 perfons ; vl-^. 358 

 males, and 427 females. 



CERUMEN, or Ear-Wax, Chemical Properties of. This 

 fubftance is nearly infoiuble in water. Alcohol, when affirted 

 by heat, diffolves five-eighths of the cerumen ; the remainder 

 is ftated by Vauquelin to poftefs the properties of albumen 

 mixed with a little oily matter : when the alcoholic folution 

 is evaporated, it leaves a deep orange-refiduum of a very 

 bitter taife, having the fmell and confiftence of turpentine. 

 It melts when heated, evaporates in a white fmoke, without 

 leaving any refiduum, and in fliort refembles the refm of 



hilt. 



