SUI.

SUL

( 3 S 6 )

afcertained; and if that of the fulphuric acidbe wanted, it mu(t be obtained by convertingit to a iu -phat of barytes, having previouilyfaturated the excels of alkali by muriatic acid.

There docs not appear to be any properfupi’r/ulpbat of lime, an excefs of acid only ren-dering the fulphat more foluble, and it crytlal-Jizes irorn its acid folution in its common neu-tral llate.

StTLPHAT OF STRONTIAN.

T his fait has been found native in England,near Briftcl; in Pennfyivania ; and more l .ti .ynear Paris . It has already been defciibed underthe article Cceleftine.

Sul phat of itrontian is a fait without tafteand frnell It is nearly infoluble in water, butnot ablolutdy fo, for Klaproth found that apound of water boiled on a quantity of this ful-p.'-nt diiloived about 3 grains. It is not de-contpoled by any (ingle acid; but barytes, aloneor in combination, takes irom it its acid, withwhich barytes has the greater affinity. Sulphatof Itrontian is alio decompofed by the carbon-ated fixed alkalies, and with much more eafe inthe nioiit way than the fillphat of barytes.Sulphat of itrontian, like the barytic fulphat,is readily foluble in iulphuric acid, and preci-pitable thence by dilution with water. Phisfait is decompofed by fufion with charcoal intoa fulphuret.

The analyfis of the native fulphat has beenundertaken by Klaproth , 4 by Vauquelin/ andby Mr. Clay field the discoverer of it in thiscountry,* and the refults of thefe chemiitshave a very clofe agreement.

The method to be followed in thefe analyfesis very fimple. Reduce a given quantity of itto fine powder, digeft it in a warm tempera-ture with a few ounces of dilute muriatic acid,which will feparate any iron, lime, or fulphatof lime which it may contain, but will nottouch the fulphat of itrontian; then boil theinfoluble refidue for an hour with thrice itsweight of very pure carbonat of potafh dif-•folvcd in water, which will effect a compleatdecouipofition, the fulphuric acid of the faitwill remain in folution with the potafh, and abulky white powder will fubnde which is car-bonat of Itrontian. _ The quantity of fulphuncacid is to be alcerta&cd by fir It fuper-faturatingthe folution with muriatic add, and then add-ing muriat or acotite of barytes as long as anyprecipitate falls down, which is baryPc lulphat,and fhould be walked, dried, ignited, and

s Anal. Effiiys. '-Jovrn. Acs Joints, torn. 7 >

weighed. The carbonat of flrontian remainingmay be immediately wafheu, dried, and ignited,and from its weight that of the Itrontian may beinferred; but to be certain that ail the lulphatof flrontian has been decompoied, it will bebetter to rediffoive the carbonat in dilute nitriccr muriatic acid (by which any undecompo,edfulphat will be left behind) and precipitate itby carbonat- d ammonia at a boning heat, af-ter which the carbonated earth niay Ia dried.If any admixture of lu.phated barytes is fuf-pected, which is feldorn t(ie cafe, proceed asabove, but initead or finally decompofing ihcmuriatic i'oludon of the earth by carbonatedammonia, evaporate it to the cryltallizingpoint, when, after {landing for a time, themuriat of barytes will appear in its proper formof white opake tabular cryllais, whereas themuriat of Jlrontian leparates in needled ciyftals,which latter may be further diihnguifhed bygiving a red colour to the flame of alcohol.

With regard to the refu'ts of the differentanalyfes, Klaproth found that ico grs. of thefulphat decompofed in the manner above-men-tioned, produced 1 2 4. grs. of ignited luiphat ofbarytes, and 82 grs. of carbonated flrontian.The fupirur'c acid of the former lie reckons asa third of the weight, or abou: 42 grs.; andthe purr flrontian of the latter at 58 grs. hav-ing found by former experiments that 100 grs.of ignited carbonat of Itrontian loft 30 grs. ofcarbonic acid by effervefeence, and that theremaining 70 per cent, were (to a trifling refi-due) pure flrontian.

A hundred parts of pure fulphat of flrontiantherefore will contain according to this eminentchemift, nearly,

Real fulphuric acid -Strontian — — -

42 grs.58

100.

The analyfis of Vauquelin is fo far imperfedlthat it only goes to alcertain the quantity offlrontian in the fulphat. By his experiments167 parts of the fulphat gave 129 parts of thecarbonat, which (following Klaproth ’s propor-tions) would give 54 of flrontian in too or thefulphat.

Laftly, Mr. Clayfield, whofe analyfis feemsconducted with care and fkill, and who aicer-tained both the quantity of earth and of acid,gives the compofmon of this fulphat almoftexaCtly the fame as that of Klaproth . He alfo

- 37 > ’ Nicholfon’s Journal, 4to. vol. 3,p, 337.