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Full text of "Chemical recreations : a compendium of experimental chemistry"

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LIEMICAL BECREATIONS. I 

^ ■ I 

PART 1. 

CHEMICAL MANIPULATION. 
ANALYSIS BY THE BLOWPII'E. 



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ADVERTISEMENT. 



Tub tblloiTing works, rormlng tlie sequel of the praseot, will be puh 
li*hed ahortlj; — 

CHEMICAL RECREATIONS. 



Van H. 

A COURSE OF TESTING, 

Cumjridng u Elmmtuj Inttodactloa la QnillUtiva Chem 
This Ptrt will Include Instructlona for teuhing ' 
Testing," by means of which, large classes of Students 
initiated into the practice of Analysis. 



Vai vet. 

SYSTEMATIC CHEMISTRY, 

Comprising e Cempendioua Account of Chemical Elements and their . 

Compounds, illustrated by numerous Experiments, adapted far repeti- | 

tion in schools by means of cheap Apparatus. I 



, Goosic 



CHEMICAL RECREATIONS: 



COMPENDIUM 



EXPERIMENTAL OHEMISTBY. 



JOHN JOSEPH GRIFFIN, 



S^t Eig^m Sbflfon. 



PART FIRST, 

CHEMICAL MANIPULATION, 

ANALYSIS BY THE BLOWPIPE. 



GLASGOW; 
PUBLISHED BY RICHARD GRIFFIN AND CO.; 

AND TBOtfAB TEGQ AND BON, LONDON. 



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«0 

C CONTENTS. 





PBKFACS to THS ElOBTB Editioh, - , . . 
PBSFACX to TBI SErBNTB EDITIOK, . . . 
iNTBODnCTWN, ....... 

Nature of Chemistry, - - . - 
Objects of Chemist^, . . . . 
. Use of CbemiBtrr, . . . - 
Methods of Chemici] Resau-ch, 
Different Classes of Eipertments, 
fa} DstomilnKtiTe Experiments, - 
Cb) DemonstrstlvB Eiperlmenls, - 
CcJ Productive Experiments, 
Different Sorts of Cliemicsl Subatuicea, 
Tlie Cause ol Cbemlcit Combination, 



Van fi. 

CHEMICAL MANIPULATION. 
PitiLiMlNiBT Notice, 1 

POLVBttlSATION, .,....--- 8 

MortaTB of rarious Substances, - .... 2 

Anvil and Hammer, ...... 4 

Sifting and Washing, 3 

Gr»ni3ation, ....---- li 

SOLOTIOH, --. .(i 

Solubility, Insolubility, Solvent 6 

Saturation, Dilution 7 

Vessels for tbls Operation, 7 

^ . InMrtion of Cbarges into Vesaela, - - - , 13 

^ Decoction, Digestion, Infusion, .... lij 

, LIxivlation, Maceration, ----- - IB 

~ Exercises on Solution, . . - . - 18 

' Mobr'a Condenser, ---.-.- 877 

^ APPI-ICAIION OF HiAT, .-..- .- 17 

Small GUIS Spirit Lamp 17 

Small Tin Spi^rit Lamp, 18 

n Small Stoneware Spirit Lamp, ----- 81 

S Large Circular Wick Spirit Lamp, - . - 19, 881 

Oil lamps, lH,8i, 8g 

■^ Gas Light Apparatus, 23, 2^ 

LampPumac 25,880 

a Furnaces ^-Chauffer, ...... 2a 

<j Luhme's Univenal, - ... - 89 

i Wind Furnace, 30 

V Cupellation, SB 

Blast Furnace, - - - . - 33 



«glc 



SopruiTS roit Apfahatus, ... 

Supports for Sinill Veuvia, - 
Block SupportB, ... 

Retort Holder or Triangle Support, 
Guv LusBic'9 Retort Holder, 
SBfttroem's Retort Holder, - 



Vies shaped Holder, . 
Table sbsped Holder, - 

aliiider Holder, 
italllc Tube Holder, - 
Benelius's Supports, - 
Universal Support, 
Holder far Basins, Lamp, &c. 



CtI 

Mei 



PniClFITATIOH, 



Testing, . . ._ 

Tests, Re.^enta, Precipitants, 45 

Neutralisation, Aciditj, Alcalinlty, ... 46 

Coloured Test Books, ...... 47 

Process of Testing, 47 

Rose's Test Tubes, ....... 49 

Tube Frames, 60, B84 

Stock Tube Rack 884 

Conical Test Giasses, ...... 58 

Preparation of Re.Bgents, ...... 55 

Truis>asation; Dropping Tubes, ... .37,81^ 

TIOH, ........ ..60 

Beaker Glasses 6S 

EierciseB and Class Eiperlmenta, .... 03 

H, 63 

How to Fold Fillers, 64, 70 

Proper Shape of Funnels 64 

How to Support Funnels, 6S, !S6 

Routine of Filtration, 67 

Decantatlon, ........69 

How to FUter without a Funnel 71 

Cutting of Filters, 73 

Circular Filters, 78 

Proper Paper for Filtration, 76 

Calculationof the Ashes of Filters, ... 79 

Washino of Precipitate — Editlcokation, .... 78 

Berzellus's Washing Battle, .... SO 

Solution of Precipitates, ...... M 

EvAPomjTioN, -......,. 84 

Berlin Porcelain Capsules, ..... 85 

Berlin Porcelain Deep Basins, ... - 86 

Stoneware Capsules, ....... S8S 

Stoneware Deep Basins, 886 

Process of Ersporation, ...... He 

Water Bath, 8B, 885 

Handle for Basins, 886 

Cbtstallisation, ......... 91 

Eiercisea and Class Experimenls, .... 03 

Iqnitioh, .......... 95 

Foil and Spoon Supports, ...... gci 

Crucibles, ^atinum, ffj 

Berlin Porcelain, . . . . 96, SNO 

Hessian, 99 

General Directions for Operating, .... 100 

Fusion, Reduction, Fluies, 108 

Sublimation, .......... lOS 

Sublimation in Glass Tubes, ..... lO^t 

Exercises and Class Eiperinunta, 



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COMTINTS. 



'HE BlOWPIPI, - . . . . 

Description of the Kewpipe, - . . 

Proper kind of Combustible lot tbe Flune, 

Candle 



How to produce the BliHt of Air, - - - . 114 

Uon to produce a Ste&dy Jet of Flune, - - - US 

How Co eSbct Oxidation and Redaction, . . lid 

Means of supporting Object! in the Flame, • - IID 

Open Glass Tube, . - - . , 121 

Closed Glass Tube ISS 

Plates of Charcoal, 188 

Platinum Tongs, 18* 

Platinum Foil 186 

Platinum Wire, ISS 

Copper Wire, 186 

Fluxes used with the Sowpipe, .... 186 

Boies to hold the Fluxe 127, 8S7 

Miscellaneous Apparatus, IW 

Proper slie of the Assay, 189 

Proper Table to work at, 189 

Boi to hold the Apparatus, .... 130, 887 

AN*I.I81B BY THB BlOWPIPB, ]31 

Operation 1. Hie Substance Is heated in a closed Glaia Tube, 138 
S. It is heated in the open air, . . . .141 

3. It is heated in a Glass Tube open at both ends, 160 

4. It is fused with Carbonate of Soda, - . 104 

5. It is fused with Microcosmic Salt, - - - 174 

6. It is fused with Borax, .... ITG 
T>])le of Minerals that Intumesce, - - - • 148 
Table of Minerals that are Infusible, ... 160 
Table of Minerals that are Fusible, .... 167 
Table of Minerals that Fuse on the edges, - . 168 
Coloured Beads produced by Micrecosmic Salt, . . ITH 
Coloured Beads produced by Borai, ... 190 
Minerals adapted for Analysis, ..... 1S8 

Til Bxerciiei tijwn tlut Section art Bppmled to each pagt. 

Distillation, ......... igft 

Distillation In the large way, ..... 1S4 

Distillation for Analytical purposes, ... 1^7 

Distillation of Volatile Oils, 188 

Distillation in Retorts, - 192 

Distill ation in tb 



Method of Operating 19S, 190 

Best means of effecting Conden-"— '" 

Distillation of Oil of Vitriol, . 



s CondenSkUon, 



11 for smaU Operations, . . . . 88H 

Distillation of Water, 889 

Distillation of Muriatic Add, 890 

Metallic Still for Volatile Oils, .... 890 

Mjihacbiiint OF Gases, ........ 806 

Vessels required for this Operation, ... 800 

Method ofpn'^^'l'QE ^ '"•^'' > Gas> ... 807 

Clark's Gas Bottle, 809 

Collacting and Transferring of Gases, . - .811 

Stoneware Gas Holder, 814 

Stoneware Pneumatic Trough and Shelf, . . - 819 

Japanned Tin Pneumatic Trough, .... 816 



Mahaqsmbnt or GjISIS cmtinwd. 

Mercuiy Trough : — Berlin parc«l&ln, ■ ... Sll 

Stone ware , .... 818 

Coopw's Mereuriil Receiver, - - . - . aS 

GluB pDeunutic Trough, ..... 2Sl 

G&hn's Cylinder Holder, 238, 283 

Collectisf of Gksea bv diiplacement, ... SS3 

Drying of Giws, ' , BW 

MeunrinEimdWetghlDcofGuef, ... 829 

Metallic Reductions sSbcled bv Gtees, ... 885 

Solution of Gases S27 

Woulfe's Appkntua for Compound I^ittllatloii, . . 889 

Tube of Safety, 831 

WbCOHINO and MlAgUBINO, K34 

Taking of SpeciAcGraviUee, ..... 23S 

Glass Blowing, ......... 83B 

Common Kowpipe, ...... 83B 

Table aowpipe, 1^0 

GlMa Hower's Lamp 81b 

Jets or Nozdes for the Blowpipe, .... 311 

Means of obtaining a good Flame, .... 248 

Places lit to work in, 243 

Choice of Glass Tubes, 843 

Preparation of Tubes belbre heating thwn, - . . S14 

Sites of Glass Tubes, 845 

MeUiod of presenting Tubes to the Flune, . . 2»6 

Fundamental Operations in (^assnonlng: . - 34N 

I. Cutting, 818 

8. Bordering, 250 

3. Widening, 2SB 

4. Dranlngoat, 868 

fl. Choking 253 

6. Sealing, 853 

7. Bowlig, 254 

8. Piercing, 267 

g. Bending, 858 

10. Soldering, 259 

The LAHiHATOiy, ......... 261 

General Hints on the Laboratory, and on the Conver. 
slan of School rooms and Parloura into temponiy 

Laborat^H'ies, ....... 861 

Ventilation, 868 

WorkT^e, 264 

Cork Boring and Cutting, 265 

Elastic Tube Making, 809 

Glass Cutting and Grinding 87D 

Working of Metal 278 

Cementfng, 873 

Cleansing, ........ 275 

Ai>d:tiokb to Pbecbdino Sbotiohs, . , - . . 277 

Appendix, containing Prices of Chemical Apparatus, and of 

Cabinets of Minerals and Rocks, .... 293 



»-i h, CoogW 



PREFACE. 



XscEsstTY, rather than choice, obliges me to feane the pi-eaent 
edition of Chehicai, Recreations in detachmsnts. I intended 
to hare publiahed the whole at once, but the limited time 
which my commercial aYOcations permit me to devote to science, 
prohibits any approach to a speedy execution of the amendments 
which I had planned upon the preceding edition of this work, 
and incautiously attempted to effect. A comparison of the pre- 
sent publication with the corresponding portion of the seventh 
edition of Coehical Recreations, will satisfy the reader that the 
amendments introduced are to such an extent, and of such a 
character, as, in feet, to constitute a new work. The alterations 
which I intend to make upon other portions, though not perhaps 
BO rerolutionary as those which I have made upon tins por- 
tion, are, nerertheleas, such BB can only be effected by an ex- 
penditure of time BO considerable, that 1 find myself under the 
necesaitj, either of delaying the publication of the whole work 
for an indefinite period, or of publishing apart the portion which 
is now finished, and which comprehends a complete awi impor- 
tant mbject. In this dilemma, I adopt the latter alternative, 
and publish this essay on Manipulation, with an engagement 
to finish the residue of the work at the earhest opportunity. 

I am the mora induced to take this course, by the commen- 
dations which a number of my chemical friends have been pleased ' 
to pass upon some new chemical apparatus, of which, in a 
^•ecies of chemico-commercial experiment, I have superintended 
the manuiactnre, with an endeavour so to combine and organise 
it, as to reduce the expoise of apparatus to such a degree as to 



make the introduction of chemical tuition into schools no longer 
to be dreaded by teachen, as they have hitherto dreaded it, M a 
certain vturee iff pecuniaTy log*. 

An account of my ottempts to discover, to collect, or to con- 
ttruct cheap chemical apparatus, and to rimplify the perform- 
ance of analytical proceasea, is, therefore, here placed before 
the public, and I will trespass upon the reader's attention with 
a few explanatory observations. My study has been, in the first 
place, to develope the nature and objects of the more impor- 
tant processes of the science; in the next place, to consider the 
means and appliances whereby the chemists of modem times are 
accustomed to bring out the reanlta of these proceases; andfinally, 
to produce such modifications of those experimental means, as, 
without abating from their utility, should operate to the reduc- 
tion of the three great evils of high cost, scarcity, and difficulty 
of management. That the prevalence of these evils has hitherto 
repressed the extensive difhsion of chemical knowledge, is un- 
deniable. I thought it worth while to determine whether these 
curbing powers prevailed of necessity, or from accident. My 
investigations have led me to draw the latter conclusion. 1 find 
that the erilg referred to can be readily overcome, and I shall 
show in the following pages, that serviceable chemical apparatus 
can be made as cheap, as plentiful, and as easy to nse, as the 
instmimcnta which have long been employed in illustrating the 
usual school-taught sciences of geography,gcometry, and astro- 



It is needless to inform the reader how much trouble and 
time have been bestowed upon the investigations and experi- 
ments which the execution of such a work compelled me to 
undertake. The accumulation of existing descriptive matter, 
though that has been gathered &om many distant and scattered 
places, formed but a small part of the necessary labour. The 
making and trial of innumerable modihed forms of apparatus, 
was a much more arduous task; so also was that of gathering 
apparatus and materials &om France, Prussia, Bohemia, Austria, 
Saxony, and Sweden, as special purposes rendered necessary. 
But the superintendence of the manufacture of large quantities 
of such aiticlee as were proven to be most ose&l, a manufoc- 



tore persevered La nnder conaiderable difficuUieB, for the pur- 
pose of resolving the question of hou) hte the reduction of price* 
could be carried under a guppo^tioug extension of demand for ap- 
parattts — this was the most trouble»dme, tedious, and expensive 
hranch of the e»c[uiTy. 

The results of these researches, however, are the production 
of many new and cheap InstnimeutB, adapted for purposes which 
formerly required those of an expensive kind, and the contrir 
vanoe of many new and easy methods of experimenting, ^- 
plicable to cases which previously were attended by numerous 
difiiculties. By the introduction of stoneware apparatus, and 
by making such alterations in the form of many vessels as faci- 
litates their adaptation to different purposes, I have at once re- 
duced their price, and lessened the number necessary for general 
use; while, by the organization of apparatus adapted for the 
aimultaneoua performance of processes by lai^e classes of stu- 
dents; by the use of circular filters, test boolis, improved tube 
holders, and other contrivances; 1 have provided the means of 
sivi»o TiHB in experimenting, which my experience leads me 
to consider to be a matter of greater importance than even the 
reduction in price of the apparatus. The tenden^ of these re- 
sults will be to facilitate the teaching of elementary chemistry, 
and consequently to lessen its expense ; to facilitate the prac- 
tice of chemical aaidysis, and consequently to extend more 
widely the beneficial applications of Chemistry among all per- 
sons whose professions or manufactures render them in any 
degree dependent upon that science. 

The application of the commercial principle of creating a 
demand for goods, by proffering a cheap supply, has never 
hitherto been made to chemical apparatus. 1 flatter myself 
with the hope that the present attempt will not become remark- 
able by merely demonstrating that the diffusion of science can- 
not be promoted by such a means. I rely too strongly upon 
the JQStness of the commercial axiom, to anticipate such a re- 
sult as that. On the contrary, 1 trust that a popular deare 
for the acquisition of chemical knowledge will be roused where 
it b now dormant, and created where it does not exist, by the 
power which this new apparatus confers of acquiring that know- 



ledge cheaply ftod readily ; aiid I am induced to hope that the 
work which embraces the dettdk of my enquiries, coupled with 
instmctiona for etiabling others to avoid the difBculties which 
I have encountered, aad to reach their object by a ahorier cut, 
or "royal road,' will not be considered by practical persons as 
a useless addition to British chemical literature. 



I take this opportunity of acknowledging the obligations 
which I am under for many hints and articles contained in the 
following pa^s, to the undermentioned woika ; — 

Chemische Operationen und Qeraethschaflen, von J. Jacob Ber- 

zelius, 1831. 
Die Anwendnng dea Loethrohrs, von J. Jacob Beizelius, Dritte 

Aufii^e, 1837. 
Houdbuch der analytischea Chemie, von Heinrich Rose, Dritte 

Aufiage, 1833. 
Lehrbucb der Chemie, von E. Mitscherllch, 1835. 
Die Probirkunst mit dem LoetJirohre, von C. F. Plattner, 1835. 

CommnnicBtiona from personal frienda, and abstracts from 
works not cited above, are generally quoted as such iti the text. 



D,g,nz»-it.,Goo;jli: 



PREFACE TO THE SEVENTH EDITION 



CHEMICAL. RECREATIONS. 



A LITTLE book like the present baa BO claim to a long pre&ce. 
A few words will explain its plan and tendency. 

It exhibits a condensed account of the natnre and objects of 
chemistry, and of the method by which it may be learnt. 

It cont^ns a description of the handiest methods of making 
chemical experiments on a small scale, either to prove what is 
known, or to determine what la unknown. 

It embraces an account of the properties of the elementary 
bodies, and of the most important compounds originated by their 
combinations. 

It contains a series of experiments, calcolated to display the 
remarkable properties of particular substances, and the general 
nature of chemical phenomena. These experiments will be 
found as interesting in performance, as instmclive in their re- 
sults. They are such as can be executed with little cost aad 
without difficulty. 

Lastly, the work unfolds the principles of theoretical chemis- 
try, examines the groundwork and superHtmcture of the pre- 
vuling theory of Chemistry, points out its defects and the con- 
fusion to which the defects gire rise, suggests a remedy, and 
presents a Nomenclatore, a System of Arrangement, and a 
Theory of Combination, founded upon new principlee. 

Such is the plan, and such the tendency of this work. It has 
the fault of taking perhaps too wide a drcnit, and of bringing 
together subjects adapted for students of a different status; but 



XIT 1>mxFACB TO THS SBTBNTH 

I hsTs been induced to adopt thia course by a deare that my 
readers should be toaght to thitdt aa well as to experimetit, and 
thus be gnalified, at an early part of their stody, to discriminate 
between the tme and the folse, and acqnire-the &cts of the 
science without being mystified by its fictions. 

The critic who may incline to censoriousneas, is reminded that 
the task 1 hare undertaken is no easy one. To reform the no- 
menclatnre of ohemJatry, is to cleanse the Augean stable, where 
rubbish has been accumulating for forty yeat». 

Oli^sv, Jon* 1, IgM. 



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INTBODUCTION. 



Nature or Cheuibtrt. — ChenuBtry is tlie science which makes 
known to us the pioperties of the component particles of all 
oatural bodice. I epeok not only of those compound particlca 
which are the result of oivanisation, but of the ultimate^ indivi- 
dble, or etemeaiary particles. It treats of the infinitely Tarious 
aorU of sabatances, and of the exact detennioation of their dif- 
ferences. It exhibits the jneana by which the component parts 
of compound bodies can be separated from oae another, or by 
which the elements of ccmpoundB can be made to combine t(>- 
gether. In fine, it shows by what contrivances the corpuscles 
which constitate the world, can be most beneficially applied to 
the serrice of man. 

Objects oy CuRMiffrar. — The objects of chemistry are inex- 
hanstlble. It oadertakes the examination of all sobstances 
which act upon the senses. It seeks to determine the proper- 
ties of those anhstances, the number and proportion of their 
component particles, the individual natore of those components, 
and the properties of all other compounds which can be pro- 
duced by their combination, either in different numbers or in 
different proportions. There are no bounds to the researchea of 
chemistry; because, at what«Tor point ita operations commence, 
there is no telling to what they may lead. Indeed, so infinitely 
Taried are ita objects, that it is an everlastii^ source of occupa- 
tion and amusement; and while, on this account, it receives the 
attention of the curious philosopher, it claims the notice of all 
men, from its ntilfty in the aits W which the comforts and exis- 
tence of civilised life are promoted and supported. 

UsB OF Chbuistrt. — The great importance of the science of 
Chemistry is rendered evident by the following considerations: 
It is useful in explaining natural phenomena: indeed, in deter- 
mining the Gonstitutioa of the atmosphere, in iuTestigating t\>£ 



ZTl INTKODDCTION. 

changes to which, it is subject, the variations of temperature, 
the laws of winds, dew, run, hall, and snow. Chemistry is our 
principa], our only satiafactoiT guide. These remaikable 
changes in the face of nature — changes wliich, because &miliar, 
do not produce any emotion in the mind, though in themselres 
truly wondorfol — are chemical operations on a magnificent 
scale, and can only be explained by chemical laws. 

In tDoa'a reaearcheB into the nature of the things whence he 
derives the means of hia comfort, his happiness, his luxuries, 
and eren his existence — iu examining the various obj ecta which 
compose the mineral, the vegetable, and the animal kingdoms. 
Chemistry is essentially requisite ibr the successful progress of 
his inquiries. 

In considering the application of Chemistiy to the improve- 
ment of the arts of civiliEcd life, a wide field of contemplation 
opens to our view. So extensive, indeed, are its influence and 
importance, that, in most of the arts, many of the processes — 
in some all that are employed, depend on chemical principles. 
^. The bare mention of some of these arts will suggest ample illus- 
\ trations of its extenrive ntihty. 

In the medical art, so great is the service of a knowledge of _ 
Chemistry, that its practical acguiaition is now universally re- 
garded as an essential branch of a medical education. In the 
art of extracting metals from their ores, in purifying and com- 
bining them with each other, and in forming instruments and 
metals — whether for useful or ornamental purpose — almost all 
the processes are purely chemical. The arts of glass and por- 
celaui making, of tanning, soap-making, dyeing, and bleaching, 
depend entirely upon chemistry; and all the processes in bak- 
ing, brewing, and distilling, most of the culinary arts, and many 
other processes in domestic economy, are chemical operations. 
In short, wherever, in any of the processes of nature or of art, 
the accumulation or the diminution of heat takes place — wher- 
ever a sensible change is to be efiecled by heat~wherever sub- 
stances in combination are to be separated — -wherever the union 
of simple substances and the formation of new compounds are 
to be effected — the operations and their results can only be ex- 
plained on chemical principles. 

From this general view of the extensive applications of che- 
mical science to the arts, those who have not considered the ob- 
jects which it embraces will be enabled to judge of the impor- 
tance of this study. 

If we consider ChemiBtiv purely as a science, we shall find 
no subject better calculated te encourage that generous love of 
truth which confers dianity and superiority on those who suc- 
cessfully pursue it. There is no science which holds out more 
interesting subjects of research, and none which affords more 
striking proo& of the wisdom and ]>eneficence of the Creator of 
the universe. A machine constructed by human art, is admired 
in proptntion te the simplicity of its condivance, to the extent 



INTRODIJCTION. XVU 

of its useFulncsB, and to the niceneH of its adaptations. But 
the works of man siuk into nothing when brought into com- 
pariaon with the works of nature. When we examine the 
liiTiner, every Btep of our pn^^ress is obscured with comparative 
clumauess and defect : in contemplating the latter, we behold 
perfection rise on perfection, and more exquisite wonders still 
meeting our view. It is the merit of Chemistry, that by its aid 
we are enabled to take a minuter snrvey of the great system of 
the univeree. And wo find, so far a« our limited powers can 
comprehend it, that the whole is nicely balanced and adjusted, 
and that ail its changes tend to the most beneficial purposes- 
Circumstances which; on a auperficial view, were seeming im- 
perfections and defects, a closer inspection points out to be real 
t^cellencies. In all the singular and surprising changes which 
everywhere present themselves, the more closely we observe 
and examine them, the more do we admire the simple means by 
which they are accomplished, and the intelligent desiKU and 
perfect wisdom displayed in tho beneficial ends to which they 
are directed. 

To these eonsiderations respecting the usefiilneas of Chemis- 
try, we may add another, which, at a period when Chemistry is 
taking its proper place in schools as a branch of general educa- 
tion, is not without its interest. This consideration is, that 
Chemistry is a subject qualified to train both the mind and the 
handf of young people to habits of industry, regolaritj', and 
order. It teaches the doctrine that accurate and extensiTe ob- 
servation is nec^fiary for the accumulation of facts; that carefal 



and exact comparison is necessary ibr the reduction of these 
&cts to general statements; that logical precision is necessary 
in estimating the relative value of various problematical state- 
ments on points where positive information is wanting; that, 
consequently, the chemist must study to become capable of 
judging according to prerumptive evidence, and in that manner 
habituate himself to the formation of sound opinions on all sub- 
jects that come under his cognizance. 

Again, the necessity of observing the most scrupulous and 
constant regard to cleaniinese in experimenting, as being indis- 
pensable to success, must gradually induce habits of neatness 
and cleanliness even in the most slovenly; while the equally una- 
voidable necessity of carrying on the different steps of an oper- 
ation in an ordeny and cautious manner, must have a corres- 
ponding moral influence upon persons of the most careless dis- 

Independently, therefore, of any advant^s to be hoped for 
&om the possession of the mere facts of Chemistry, setting en* 
tirely out of view the applications, either of the principles or 
the details of the science to the prospective commercial or scien- 
tific pursuits of the young student, there is, in the mental and 
moral discipline which its study affords, high inducements for 
malting chemistry a stated branch of Uberal education. 



ZVin INTRODDCnOK. 

Methods of Chekio&l Rheiiuir. — It has been demonBtrated 
by the experinients of chemists, that the marvelloas diversity of 
appearance under which bodiM are presented to the eye, and 
the unceasing changes to which thev are subject, are oceastoned 
bv the mutoal reactions of a sm^ number of anchang«able 
elementary porticlee. The distinctiTe properties of these psr- 
tjcles, the nature of the phenomena which mark their reactions, 
the methods of causing them to combine, the properties of the 
resulting oomp<Minds, and the methods of decomposing these 
compounds, — are, consequently, the objecte which the chemical 
student is called upon to inTestigate. 

There are two methods of proceeding in the scqnisition of 
chemical knowledge ; these are o^ed anafyfit and tynthetit, 
Aniltbib means the art of geparatntg the oonstitnents of com- 
pound bodies, — STtrcnssis the art of fbnning componnds, by 
the putting together, or efiectmg the combination, of their com- 
ponent parttclea. Both an^ysis and synthesis are praetic^y 
effected by the peiformmg of oeit^ proceBes or operations, 
thence called chemical operafion*. 

The properties of natural bodies, whether they be simple or 
compound, native or fectitious, can never be determined d priori; 
they can he discovered only by actual trial. When an un- 
known substance is presented to a chemist for examination, lie 
submits it to certain trial*, or performs certain operalioTts upon 
it. He examines, for example, the relation of the unknown 
body to heat, light, water, adds, alcaliea, and other liquids. 
These triak have particular name» given to them, lor the sake 
of convenience in the communication of knowledge. If a sub- 
stance is exposed to a red heat, the operation is termed lowmoH. 
If the substance melts, the operation is termed fosios. If the 
substance, on being put into water, dlasolvet or disappears, the 
operation is termed soLirnar', and the resulting liquid is called 
a solution. If the solution is exposed to heat so as to cause the 
water to rise in vnpour, the operation is termed bta?obation; 
or if the operation is so performed that the vapour is collected 
and reconverted into water, the operation is termed disttlla- 
TTON. If, on the contrary, the solution, inst«ad of being ex- 
posed to evaporation, is mixed with some liquid which causes 
the production of a solid subslaTtce or powder, the operation is 
caUed pitGcii'iT«T[ON ; and if means be taken to separate the solid 
powder from the residual Hquid, by strainii^ thraugh a porous 
substance, this operation is termed filtiuition. 

The performance of these operations communieatra to the che- 
mist a certain degree of knowledge respecting the properties of 
the substance operated upon. If the substance does not melt 
when exposed to a strong degree of heat, it is said to be ir)/u#>- 
ble. If it does not dissolve Mien placed in a hquid, it is stdd to 
be insoMile. A description of the results of a series of such ex- 
periments, is the chemical character of the substance. We can- 
not account for the properties thus found to belong to a sub- 



INTRODDCnoK. XIX 

stance. No chemistcango fiu1JlertiwIltbeaflc«rb>mmentof■im' 
ple facta. The sagacity of man le insoffident to dettmiiiie wht 
B givrai rabatanoe is soluble ca insoluble, fiuible or iniruible. 
The no<ur« Q^<A« power which causes AuKm or solubility, iann- 
known. And, indeed, this is thecasewith regard to all phj'sical 
pbenomena, the forest yUaeh produce them ore unfctunm lo man, 
except by thHr t^iett. 

The more nnmerous the opei^ons peHbrmed upon a substance, 
the more acoor&te is the knowledge aeqnired respeirting its 
properties; prorided the c^rations be suitably ocmdncted. The 
properties of a substance can neTN be whollr known. ChemistB 
Df^ta with a single fact; their daily expeneaice enlarges their 
knowledge: but, at the best, their acquaintance with the pn>- 
perties of any one body is bat limited and imperfect, Not un- 
til a Bubetanoe shall have been submitted to the action of every 
other substance, and under all possible variations of temperature, 
preffiure, and so f<xth, will its properties be wholly determined; 
and that will never be. The knowledge we pOBseas reamcting 
the properties of known elements and their compounds, is, not- 
withstanding the labours of many indnstiions chemists, still ex- 
tremely imperfect. No {owstical chemist, however young he 
may be in the science, can pursue his studies with even a mo- 
demte degree of zeal, without being enabled to add something 
almost duly to the esisting stock ot intelligence. The variety 
of unreeorded &ctB whidl continually strike the eye of an indus- 



quainted with what is already known, with what has been al- 
ready determined by the experiments of others. His next con- 
cern, to lesm something i^ch no one else has yet discovered. 
Chemistry is a science fouBded so entirely upon experiment, 
that no penwn can understand it fully unlea he peraonally per- 
fonn each experiments bb vnify its nmdamental truths. The 
healing of lecture and the reading of books, will never bcsiefit 
him who attends to nothing else ; fw Chemistry can only be 
studied to advantage praeticalty. One experiment, well conduct- 
ed, sad carefiilly obterved by the student, from first to last, will 
afford more knowledge than the mere perusal of a whole vol- 



DiFFBRENT CLASSES OF Ezra&ntBNTs.— Chcmictil experiments 
may be divided, for convfoience, intotiueesorte; namely, De- 
terminative, Demondiative, and Frodnctive. 



deores to know the natnre of it, I must make a determinative 
eapertment; ax other words, I most submit it Ut analysis, or de- 
termine by eteperiment, what it is composed of. Chemical aoa- 
\ym is of two swts, qualitative and quantitative. A qualitative 
analyas makes known the ebcmcal notiue of the ouistitaents 



XX IKTRODUCTION. 

of a compound, but not the relative quantities of those constitu- 
enta. A quantitative analysis makes known both the nature 
of the coustitueuta and the exact quantity of each by weight. 
Experiments of this sort are sIbo c^ed experimeuts of retearch. 
No man can execute an analysis without previously acquiring a 
considerable share of chemical information. Before a qualitative 
analysis can be executedjit is necessaij to become acquainted with 
the properties of all the known elements and their principal 
compounds, as well as with the methods of determining whether 
any of ttfem, on a certain occasion, be present or absent. The 
use of chemical te^U or re-agenU, depends upon the knowledspe 
previously acquired, that particular bodies, in particular cir- 
cumstances, act in a determinate manner. There is, for exam- 
ple, a liqnid called oil vitriol. 1 know that other liquids which 
contain certun mBstances in sohition, upon being mixed with 
oil of vitriol, produce a precipitate. I^ then, upon dissolving an 
unknown substance in water, and mixing the solution with oil - 
of vitriol, I obtain no precipitate, I am certified that the sub- 
stances alluded to arc not present. It is evident, that unless I 
know beforehand what sutetonces do give a precipitate with oil 
of vitriol, and what substances do not, it is useless to apply the 
test ; because whether I see a precipitate or not, I acquire no 
information. A vast number of other substances serve, as well 
as oil of vitriol, the office of chemical tests, and their employ- 
ment in chemical analysis constitutes a very important part of 
chemical study. In the subsequent pages, the reader will fre- 
quently find it stated by what diversity of tests a particular sub- 
stance may be known to be present, and also mr what other 
substances any g^vea compound ig^le to act as a test. 

In quantitative analyiis, somet^^more has to be done. Sup- 
podng a man to know how to det^nll the inn«dicnts of a com- 
pound, supposing that be has detected them, he has, in quanti- 
tative an^yais, the additional task of aeparating these inKredi- 
enffl from one another, of freeing each from every possible in- 
termixture, and of determining their respective weights. In 
some cases, two substances can be separated from each other 
with ease; in other cases, the separation cannot be effected with- 
out great difficulty. The methods of separation depend alto- 
gether upon the properties of the particular substances which ore 
to be separated, and can only bo leamt by studying these pro- 
perties. But success also depends upon the skill of the operator 
m the performance of the numerous operations which occur in 
analyus. The fumons, solutions, filtnitions, and evaporationa, 
require to be performed with extraordinary care. If a drop of 
liquid fells down, or an atom of powder is blown away, the whole 
experiment is spoiled, and the labour, probably of weeks, is frc&- 
trated. To perform an analysis with accuracy, should be the 
object of a student's ambition, but if he wishes to attain that ob- 
ject he must not only industriously study the properties of che- 
mical bodies, but continuaUy accustom himself to manipulation. 



INTSODDCTtON. XZl 

that he may become dexterous in the perform aoce of thoae iqtera- 
tions upoD which the niccees of an analysis mainly depends. 

("bj. DemonttraliveExpmmetU* axe of adiSereatkiai. They 
are employed in the oommunieation of chemical knowledge. 
When s ctaemiat has discorered any thing' new, he announces 
(ha discorery, and describei an experiment by which the truth of 
his statement can be proved. This is a demonstrative experi- 
m«it. There are certain substancea which if heated at one end, 
very soon become hot at the other end; these are said to be ifood 
amductort of heat. There are other substances which on being 
heated at one end, are a long time before they become hot at 
the other end ; such substances arc called bad oondactora of heat. 
A man discovers and states that the metal called platinum is a 
bad conductor of heat. The proof of this is easy. You take a 
short wire of platinum, hold it by the fingers at one end and 
place the other end in the flame of a lamp. You find that the 
heat eomes to the fingers very slowly. Tina ia a demonstmtive 
espeiiment. As the students of a science must be supposed 
to be quite ignorant of its facts, it is the business of teachers to 
demonstrate the truth of their assertions by experiments, and 
accordingly lecturers on chemistry exhibit a great number of 
experiments. It would be in rain, however, to attempt, in a 
tAoM, to demonstrate evervthing. Want of time forbids it. But 
a teacher should be corenil not to give that as a chemical f(tct, 
which ia ificapalie of proof by a chemical experiment. This, 
however, ia a rule which many lectorera make a point of wholly 
disregarding, and theories of utter extravagance are flung out 
with a most reckless and pj^jgal hand. On thia account, I 
caution all students against ^^pvini; dogmas as &ct8, and ac- 
cepting asiertion for arguin^V I know of no sinele chemist 
upon whoso judgment I woulT found my belief. 1 nave stated 
this before. I h^ve been censured ibr stating it, and 1 state it 
AB strongly still. I admit the judgment of no man as infallible. 
Nobody B ip»e dixit should pass current in chemistry. In an ex- 
perimcutal sdence, where truth lies within a mans own reach, 
every person ought to make use of bis senses, and judge for him- 
eelf. Those who are too ready to adopt as their own the opiniona 
of another, are certain to be deceived. It ia astonishing to ob- 
serve the number of felse theories which have been propagated 
by the credulity of idle ohemista. Our chemical books contain 
■ ten thousand assertions respecting the proximate conntitvtion of 
bodies, of which iiot one ia capable of proof. In studying chemis- 
try, therefore, the student should loA attentively to the demon- 
strative experimentg. No one who is in the habit of reasoning up- 
on what he hears, and believing only what is proved, will ever 
nm the risk of talking abanrdiUea about the properties of dry 
nitric add, and other chimerical compounds, which nowhere 
exist but in the excited hnaginations ot over-credulous "philo- 
Bopbeis," 



. Mu iNTKonccnoM. 

(c). productive Experimentt. 1 hare given this Tiame to 
those experiments which have for object the production of che- 
mical substances. The Pharmacopeia is a collection of produo- 
tire exp'crinients, containing neither more nor leea than in~ 
structions for preparing or prodncing the chemical subatances 
employed in medicine. It will he underatood, of course, that 
many analytical and demonstrative e:njerimenta, are also pro- 
ductive experiments ; but I understand by the latter term, toose 
experimenla only which are made for the express purpose of pro- 
ducing chemical preparation in quantities for use. Productive 
experiments form an admirable exercise for young students. 
The preparation of the various acidn, oxides, aalta, sulphureta, 
chlorides, iodides, &c., is capable of ^mishing most useful in- 
formation respecting tbe properties of those sut«tances, and has 
. the farther heneficuil effect of habituating the student to care- 
iiil manipulation. A vaat number of substances oan be prepar~ 
ed in the »maU way, vdth the help of glass tubes, small flaaks, 
capsolce, glass plates, &c., in suifident quantities to enable the 
operator to ascertain their properties and re-actions with other 
substances. A student's spare time cannot be more agreeably 
or nsefiilly occupied than in preparing and examining oompountb 
not previously fa.Tniliar to Mm . Portions of substances so pre- 
pared may be preserved in small pill boxes, or in bits of qnill 
glass tube, dosed with corks. Productive experiments in the 
large way, are those whi(^h produce the metals, salts, acids, al- 
caliea, and other commodities of the dru^ist, the dr^alter, the 
colour maker, &c. 

The chemical properties of ^kbetance characterise equally 
the smallest portion of that BDUHjbe, or the greatest mass. That 
which can be demonstrated of a pound, can Uso be demonstrated 
of a grain. Hence chemical experiments may be,peribrmed, 
dther with lai^ portions of matter, or with small portions; and 
whether in an^ case a large or small portion should be operated 
upon, is a thmg to be determined solely by expediency. In 
trade, where productive experiments are made with a view to 
obtain preparations for sate, the quantities operated upon are 
often extremely lai^, amountinc' to thousands of tons. In 
analysis, the quantity of a body submitted to a test weighs some- 
times but the fraction of a gram. When a lecturer has to teach 
chemistry to alarge audience, it is his duty to malcc his demon- 
strative experimenla upon rather a large scale, otherwise a ma- 
jority of the persons present may not be able to perceive what 
takes place. And whenever a theory is built upon a single ex- 
periment, the lecturer should take particular care to make this 
experiment in such a manner that every person present may see 
ana comprehend it folly; for if the demonstration is not made to 
tell, the theory sinks unheeded, and the arguments grounded 
upffli it are fustian. I give this hint to the Members of Me- 



IKTEODVOTtON. XXIU 

chsnic^ Institntloiu, who hare lately adopted tlie useful practice 
of lecturing t« one another. 

As the demonstrative experimeota of the lecture room are 
unavoidably scanty and unsatjsfactoiy, the etndent who desires 
to know somewhat more of the science than he can learn there, 
must necessarily pnrsoe his studies at home. I have already 
cautioned him against believing the doffSias he hears and reads, 



without se^g the experiments which are intended to verify 
them. It is indispensaWy necesstttr, that he perform with his 
own hands the fundamental- experiments of chemistry, in the 
beat manner that his time, his apparatus, and his means admit. 
He will find it of importance in this cose to operate upon ex- 
tremely small portions of matter ; for he will then not only 
BBve time and money, but often be enabled to perform a succeea- 
fiil experiment, where, by operating upon a large mass, he would 
as certainly fail. The prqwration of the gases, the formation and 
crystallisation of salts, the application of tests, and a thousand 
other entertaining and instructive experiments can all be per- 
Ibrmed by the student, better on a small sc^e thfm iu the large 
way ; nay more, a student in his closet very frequently succe^ 
in performing an experiment which fails on the lecture table of 
the professor ; for the accidents which attend the hurry and 
business of a lecture room produce unavoidable disappointment. 
This, therefore, is a circumstance of which the chemical student 
should be prepared to take every advantage. The faculty of 
experimentmg with accuracy, facility, and economy, ought to 
be gained as spcadily as possible ; for it is upon that faculty that 
tie progress of the young chemist is principally dependent. 

Different Soais of Cuehicit. Substances. — All natural bodies 
are either gimple or comp(mnd. Those substances ate simple, 
which cannot, by any known method be separated, decomposed, 
or divided,- in such a manner as to produce particles different in 
their properties from one another, or from the original sub- 
stances. On the oHier hand, those substances are compound, 
which experiment is capable of resolving into particles of an un- 
like nature. For a period of many centuries, and even till a 
very late date, there were four substances held to be simple or 
elementary. These were fire, air, earth, and water. Of these 
four bodies, all others were supposed to be constituted, though 
nobody could ever prove, or indeed ever tried to prove, that this 
was the case. The system, however, continued to be orthodox 
until very lately, when three of these imaginary element», 
namely, air, water, and earth, were proved to be compounds. 
But with respect to fire, it is still unknown whether it be simple 
or compound, or in what its essence consists, or by what causes 
its effects are produced. What the ancients considered to be 
simple bodies are no longer considered to be such ; but in place 
of these substances, the demists of modem times have elevated 
to the dignity of elements a far more numerous race. No one, 
however, dogmatically asserts now a days that the substances 



XXIV IKTRODDCTIOW. 

termed elements are absolutely of a simple natore. The ferm ■ 
element intimates no more than that the body to which it ia 
applied, has never in the opinion of niodem chemiats been sub- 
jected to decompoMtion — that it has never been divided into par- 
ticles different from one another, or from the original substance. 
The number of elenients is at present assumed to be fifty-four. 
The properties of these elements, and the experiments by which 
the separate identity of each is demouBtrated, will be described 
in a subsequent part of this work. 

The Cause of Chbmici.l Combibatio.-j. — When the elementary 
bodies are placed in contact under particular circumstances, they 
unite or combine together, and produce compound bodies. Some 
combinations are effected very readily, and some with great 
difficulty, and there are cert^n elements which can scarcely by 
any means be made to combine. The compounda produced by 
the combination of the elements, possess properties very different 
from those of the elements of which they are composed. The 
POWER, in virtue of which simple bodies can combine and produce 
compounds, is one of which the nature is totally unknown to 
man. OhemistB have learned no more than that mmple bodies, 
or bodies supposed to be simple, do combine ; bat WHY the;/ 
combijK, or mhat il ia which MiiKsa tueii combine, they have not 
discovered. Very frequently, however, the act of combining ia 
attributed to a particular occult power or principle, which ia 
called Affinity. If you ask some chemists to tell you wAj/ bodies 
combine together, they will say, because those bodies have an 
affinity for one another. But if, on the other hand, you ask the 
same chemists how they knon that bodies have an affinity for 
one another, the reply is, hecaute they cot7d>ine together. Theae 
answers show that sutm chemists have no very clear idea of what 
they talk about. They confound the notion of the act of com- 
hinmg with that of the power which causes the act of combina- 
tion to take place. Whether any two given bodies can or can- 
not enter into combination is a point capable of being decided, 
either in the affirmative or the negative, by experiment, and by 
that alone. But no experiment, or at any rate, no experiment 
which has yet been contrived, can show what is the nature of 
the governing influence which induces, or obliges, any two dif- 
ferent bodies to combine together and produce a nniiorm com- 
pound poaaessed of marked and origiiial properties. What we 
are told about affinity is mere gossip, and though the greatest 
chemists have given themselves up to gossiping, it does not fol- 
low that gosMp IB to be held sacred or venerable on tliat account. 
Wherefore, I caution all voung chemists against giving implicit 
credit to what is said to tliem about affinity, and not to believe 
any assertion which is incapable of clear conception, or wh[ch is 
repugnant to common sense ; nor yet to value that as knowledge 
and matter of fact, which, upon being closely examined, provea 
to be mere play upon words. There has been more nonsense 
written abont this affinity, and more ugly diagrams drawn in 



INTRODnCTION. XIV 

UIiistrattoD^ thereof, than about any other subject connected 
with chemistry. And the reason that so much nonsense has 
been written and published, ia, simply, that chemists have been 
desirous of enveloping their ignorance in a cloak of mystery. 
There stood the plain fiict before the world, — that bodies eom- 
Utted together, and Chemiat$ knete not uiAy,but the chemists not 
liking to eay so, and not liking even to (Ainft so, persuaded 
themselves, and then tried to convince the world, that they om 
know itthy. They said that bodies combined together in virtue 
of their affinily/or one another. This was pretty. The credu- 
loua stared, and amazement gave place to belief. 

You prove, by an experiment, tnat two given bodieB are actU' 
ally capable of entering into combination ; you proTe, in the 
lame way, that under ;particiilar circumstancea, two other bodies 
are incapable of combming together. You inquire what it ia 
which in the one case cataet the combination to take place, or in 
tlw other case pww»(« the combination from taking place. You 
are told that tiie first two bodies combine because they have an 
affinity for one another, and the latter two do not combine be- 
cause they have do affinity for one another. Now, as you are 
told, on the other hand, that the existence of an a^nity between 
two bodies is proved by the act of combination, and by that 
act alone, it is plain that this relation may be expressed in 
other words, as follows : — the first two bodies combine, becaune 
tkey combine^ and the last two do not combine, because they do 
not combine. Is there any use in this sort of explanation t 
Does it give you any idea of the power which influences combin- 
ation 7 Is the doctrine of chemical affinity anything but 
twaddle ? 

I know that bodies do eondrine, but I do not know what it ia 
that makes them combine, or why it ie that, in some cases, com- 
bination ia effected with difficulty, in others with facility. 1 
cannot perceive that any point is gained by ascribing it to affi~ 
mty, which is merely a word without an idea. 1 consider it suf- 
fiment for the communicationof knowledge to say, that such and 
such substances, put together under particular circumstances, 
either do or do not combine; and I see no reason for adding the 
tham explanation of the simple &ct, that it is because the bodies 
have or kave not an affinity for each other. 

Rejecting the doctrine of affinity, in toto, it is unnecessary for 
me to give any account of the multifarious sorts of affinity into 
which the ingenuity of sophists has divided the primary doc- 
trine, or to explain the wonder-working nomenclature applied 
to it, specially to mislead, perplex, and mystify the ignorant 
Mid the unwary: — "Simple affinity — compound affinity — elec- 
tive affinity — simple elective affinity — double elective affinity — 
complex affinity—disposing affinity — quiescent affinity- — dlvell- 
ent affinity — reciprocal affinity — resultuig affinity— id genus 

Attwd joa lU— goud night ] Kood nislit 1" 



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PART 



CHEMICAL MANIPULATION. 



0,...,, Google 



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CHEMICAL MANIPULATION. 



By the tena Chkuical Manipdiation, ia meant the art of per* 
forming chemical experimentB. Aa account of this art may be 
comprieed in a description of the varioua sorta of chemical appa- 
TStne, and of the operationa in which they are put to use. I 
purpose to aive that description in the following order. 

First, I shall describe, under the head of Pulveruation, the 
le of reducing aolid bodies to small partioles, m operation 



prep»(it<iry to all otbert. 
iRhatl exi 



explain, in the second place, the operation termed 
SoLimoR, the object of which is to bring solid 8ubct«ice« into 
the state of Uquide, in which condition they are toon easily sub- 
ject«d ta the metaiDOrphmee prodacihle by chemical power, 
than they are when in the state of solids. 

I shall sfterwffi^ exhibit the sonrces of diileTent degrees of 
Hbat, and treat of the management of lamps, tiimaee*, bbA fami- 
lar apparatue for prodncmg or applying that power. 

I shall explain the contrivances by which different sorts of 
vessels are SupronrRn, either over^res, or in other desirable 
situations above the work table. 

Then 1 shall proceed to describe the typeration of Testing, 
whereby the chemist determines the net«i« of the substances 
which are subjected to experiment; 

Of PKEciriTATioN, by wMcb different nihetances existing to- 
gether in the same liqnid are »epai«ted insia one a«nher by the 
conversion of one of Miem into a solid; 

Of Filtration, by whfch troubled Uqoids are rendered clear, 
odd precipitates tve separated Awn sotntiMU; and of fTDCiooKA- 
nw, by which {wvcipitates, after collecticA <yn a filter, an puri- 
fied by wadiiiig; 

Of EvjiFoiuTioN, by which solutions are made to yield their 
solid compiHients in the fonn of dry powdera; 

Of Cbtstallibation, by which paiticolar bodies are converted 
into those geometrical figure wl»ch are termed cryst^s; 

Of lamrioH, by which the cdcining power of a red heat is 
made to act immediately upon the object of experiment, to dry, 
hum, melt, or decompose it; 



2 PDLV£BI9AT10N. 

Of BuBLiHATiOH, Bj which many solids are converted into invi' 
Bible vapours tliaj aoon again aagume the solid state; 

Of the \]fy itt THE BloivPifb in qnaiitative Bnuly^; 

Of DisTiL).-' noK, by which simple and muted substances are 
partudJy converted into invisible vs{)oura, that subteq^nently 
BBsmne the liquid state; 

Of the PaosccTioN and MxsxBsuan or GiSBs; 

Of WEromso and Mbasoeino; 

And, finally, I shall describe the place where Chemical Mani- 
pulation is put int^ practice — the Labohatory. This section will 
comprehend instniciions on several operations relative to the 
coDstnictiiw or repair of Chemical apjiftratus, such as the blow- 
ing aud cutting of glass, the boring of corks, and so forth. 



PULVERISATION. 

RtductUm ofSoltdt to Powder, Pulvenaalitm, Levigation, Tri- 
turatioTt. — Pulverisation, strictly speaking, is a mechanical opera- 
tion, as are all the operations which tend to disnge the form, with- 
out changing the nature, of a substance; as, for example, those per- 
formed by the hammer, the knife, and the pestle; bo also are all 
those which determine the quantities of bodies: — while the opera- 
tions performed by the aid of chemical powers and agents, — by 
. fire, water, acids, and alcalies, — and those which separate the con- 
stitnents of bodies, are chemical o^ierations. Nevertheless, the 
mechanical operation of pulverisation is so essential to the suc- 
cessiul performance of many purely chemical operations, that 
the right method of execmpf,' it is necessary to be femiliarly 
known. — Brittle substances are reduced to powder by means of 
ihepeatle andiaortar, — si»He by a dexterous use of the pestle round 
the ffldes of the mortar; in fact, by rubbing, and this is what is 
termed trituration, llcitf rated blows of the peatie, which con- 
stitutes puberuafion, are made use of to powder hard bodies in 
iron mortars. Ctoly a small quantity of the substance to be 
powdered should be put into the mortar at one time. Ltvigw- 
titm is generally performed by rubbing a body, sometimes with 
the addition of water, on a fiat stone, with another stone, ronnd 
on one side to suit the hand, and flat on the other, which is 
called a muller. A qialula or Hiin flexible knife, of iron, horn, 
or bone, is employed to collect the substance under operation, 
from the sides to the centre of the flat stone or mortar. Bodies 
that are not brittle arc reduced to Email particles by meana of 
Jilef, raips, knivet, and graten. 

Mortars ore made of a great many diflerent substances; as for 
example, of wood, glass, marble, porcelain, flint, agate, bran, 
and iron. In a laige laboi^twy, where a great number c^ opera- 



PtlLVERISATlOH. 




Berlin porcdain, and another of agate. The poKelain mortar 
ought to measure 3^ inches across the top. One of this size, is 
adapted to a great variety of purposes. The agate mortar may 
measure an inch and a half acr<ss the top. One of thia fdze 
costs about 6s. If the student wishes to have an agate murtar 
ui wliich to powder mmerals for analyds, it ought to measure 
two and a b^f inches across the top. The smaller agate mortar 
ia sufficiently laige for all blowpipe experiments, and for all 
coses of quahtative analyMs. The bottom of it should be trans- 
porrait. When an agat« mortar cannot be procured, the student 
should procure a small poreelain mortar in itH atead, as it is not 
convenient to powder very small quan- 
tities of a snbstance in a Inrgc moilar. 
The marginal figure represents a Berlin 
poreelain mortar of a shape very useful 
to students. It is two inches wide, and 
has a narrow spout, useful in transfer- 
ring powders into smaU vessels, a is the 
pestle, which is of one piece, and has 
a broad end. The price of this mortar 
is Ib. Large mortu^ nearly of this shape, but with smaller 
epoats, are to be Kad of the diameters given below. The pestles 
erf these are of the shape c, and of one piece. The Wedge- 
wood's mortars used bi England are very interior in quality to 
the Berlin porcelain. The pestles of Wedgewood's mortars have 
generally a wooden handle, which is a great defect, as dirt 
lodges in the joint, and sometimes the two pieces come apart. 

biameUn of Berlin Porcelain Mortars, 2, 3J, 4J, and 5J 
inches. Pricei in Glatgow, Is. — 2b, 6d. — 4s.— Ss, 

Mortars of the above form, of tlu inferior description of por- 
celain, which in Germany is called SanitatUgut, but which, 
though very cheap, is superior in quality to most English por- 
ceWn, are sold in Glasgow at the following prices; — 

3} inches diameter, pric« Is. 6d. 

4J do. do. do 2s. 

Annexed is a representation of an apothecary's mortar of Ber- 
Hn poreelMn. It is intended for the pulverisation of large quan- 
tities of such substances as are pretty readily 
reducible to powder. The sizes are mentioned 
below. These mortars have no spout. The 
sides conveige near the upper part, and the 
bottom is broad and flat. Hence, the labour 
of pulverisiiig is much eased, and the sub- 
stance not l^ble to be thrown oiit of the 
mortar. The pestle is of one piece, and has a very broad end. 
The mortars can be had either rough or glazed internally. 
Diameter)^ 6J, 7^, and 9 inches. Prices, 4b. 6d., 7s., and 9s. 
The agate mortar is employed in the trituistion of very hard 



4 PULVSHIBATIO!*. 

Eabatances, aucb tw iniiieT^B. Care is to be taken not to strike 
it strongly with the pestle; for in consequence of tlie veins 
which intersect it, it is vety liable to crack and ftll to pieces.— 
The porcelain mortar is employed in the polverisatioa of salts, 
and m the nuxtore of powders one with another. 

As mortars of agate sxo veiy expeiuiro when of a lar^ size, 
mortars of porphyry are sometimes used. These are hftble to 
the accidents of toatag crystals of feldspar, in which case they 
become oseleai, as the holes cannot be properly filled up. Ser- 
pentine mortars are often employed in Germany by apothecftries, 
m consequence of their che^nesa. Mortars of this kind are 
now imported into Britain; they are, howerer, not very hard, 
nor fully proof against the action of adds. The sorts which 
varyinaiameterfrom2iincliesto4 inches cost in Glasgow from 
dd. to 2s. each. 

In the quantitative Mialysia of extremely hard minerals, che- 



i^ 



t^at«. The pestle A is exactly ad- 
justed to the ring B, vdiich is also 
adjusted to the mortar. The Tins, 
however, is made a little conical, 
that it may readily be taken in and 
out. The mineral to be powdered 
is placed in the oavity C, and the 
pestle is insertod in its place, and 
struck by a wooden hammer. The 
pestle is then raised a little, the 
mortsj' tapped on the aides to shake 
the powder into a new position, and 
the pestle is again struck. Bepeti- 
~' lions of this man<euvre reduce the 
mineral to a fine powder. The inm, rubbed from the mortar, 
and communicated to the powder, is removed by digesting the 
latter in diluted muriatic aci4- It commonly amounts to ^ or 1 
per cent. 

As a useful appendage to your establishment of mortars, and 
even u a substitute for mortan ia^me cases, I have to recom- 
mend you to procure a imall anvU and hammer. The anvil 
should be a block of hardened steel, about two inches square, 
and half an inch thick, well polished on the upper sur&ce. The 
hammer should be also of hardened steel, vrith a square head, 
and sharp edges, and the reverse end should be flat aad sharp 
like a ctusel. Ajivils of this sort are sold nnder the name of 
mineral stahfis. The price of them is 3b. The instrument is very 
useful in blowpipe operations, and in many others, serving to 
test the brittleness or malleability of small metallic globnles, or 
to reduce very hwrd substances to fragmeait*;, and thus prepare 
them for further pulverisation. The hammer serves also to 
strike fragments tiom minerals for analyds, and it acts so much 
the better the harder it is, and the sharper its edges. 



PDLTBEISATION. ft 

The Bubstance that is to be broken apon the asvil ahoold be 
Brat wrapped in paper, to prevent the disperaion of ita fragment^ 
when separated by the stroke of the hammer. When a small 
globule of reduced metal ia to be crushed, it should be held 
down on the anvil by a sUp of thin pH>er placed orec it, and 
secured by two fingers of tne left hand. The strokes of the 
hammer, as many as may appear to be necessary to effect the 
object, are given flpon the eleration produced under the paper 
by the mctulic bead. If the metal is brittle, the powder remdns 
under the paptr upon the samo spot. If the metal is malleable, 
it spreads out to a qiangle, the edges of which stick bo firmly to 
the paper, that it can be thereby lifted from the anvil for ex- 
amination. 

Id minerol analysts, it is of great importance that the subetonoe 
operated upon be very finely powdered. The state of fineneea 
to which a powder has been reduced, is judged of principally by 
the appearance. If the body be coloured, the colour becomes paler 
as the powder is finer, and generally at last almost wholly tusap- 
peara. When the powder, &om bemg dry and granular, assumes 
the appearance of moistness, and upon being touched by the spa- 
tula, preserves the form given to it by pressure, it is in a state of 
extreme division. In many case^ the progress of the operation 
can be judged of by rubbing a little of the powder between the 
finger and thumb, which is citable of detecting a very slight 
decree of grittiness. But *.hi^ trial caunot be made without the 
loas of a little of the powder. The powder ia transferred from 
the mortar by means of spatulas of platinum, silver, horn, ivon', 
or smooth paper. A card sometimes makes an excellent spatula, 
especially if glazed. 

When extremely hard minerals are pnlverised fbr quantitative 
analyaiB, a few other precautions require to be taken than those 
above enumerated. But it is not my purpose in this work to 
allow how to manage difficult casea of quantitative analysis; bat 
chiefly to direct your attention to the requisites for qualitative 
aoalyHis. For the information thus omitted, and for the supply 
of ail similar omissions, I refer you to Rose's MotukU of Analy- 
tical Ch^mutry. 

I shall add here a few words on some operations that are in 
SMne degree related to that of which I am treating. 

SirnNO and Wasbino are performed to separate the finer par- 
ticlee of bodiee from the coarser, which may want lurtber pul- 
verisation. For the operation of $ifting, the well-known instru- 
ment called a tieve is employed. Waihinp ia used for procuring 
powders of a more uniform degree of fineness than can be done 
oy means of a sieve; but it can only be used for such substancea 
as are not acted upon by the fluid which is used; the operation 
is chiefly reaorted to, in the pulverisation of very hard minerals 
for aoalysis. The powdered substance ia mixed wiUi water, or 
OOua convenient fluid ; tile liquid is allowed to settle for a few 






6 aOLDTION. 

momenta, and a then decaiit«(l; the eoaraet powder renuiiia 
at the bottom of the reaael, and the finer pemr» over with tha 
liqoid. By repeated deoantations in this manner, various sedi- 
dMnta are Dbt«ined of difforont dc^jees of fineness ; the last, or 
that whiah'ramaias longest Buspotded in the lii^uor, beiag the 
finest. Any cylindrical elan may be used for this puipoBe, 

GaANDLATioii signifies ttie diriaion of brittle metaJs into gtaiaa, 
m Basil particles, to fit them foi different purposes. It is petr 
fomod utiiet by ponring the melted metal into water &om » 
oonenderalile height, meanwhile stiiring the water with a bescmi, 
orfayahakingltwliilein a melted state in a box, previously well 
robbed with chalk, till the tnom^t of congelation, at which 
instant it becomes converted into powder. 

Citcauwff qf morlart. — The action of wat«r in cleansing' the 
pcovelain mortar can often b« assisted by ^rinding a little fine 
sand whh the liquid iu the mortar. Sometnnes acids a» iiects> 
saiy to take ont particular titaiua. The agate mortar frequently 
receives numerous metallio streaks when uaed in blowpipe oper- 
ations. These am be rwioved by a little wet bone tatee. 



SOLUTION. 

Solution ia effected when a solid put into a fluid entirely dia. 
appears in it, leaving the liquor clear. The body which thus 
diaappears, is said to be salable^ the liquid it diswilvctfi in, is ealled 
the tahtnt or menttntmit, and the compound liquor which it pro- 
duces, is called a tolutum. Bugar and salt are soluble bodies ; for 
when they are put into w^r, they disappear entirely. Chalk ia 
an inioluble body; for when that is pat into water, it only becomes 
diffbaed, makes the fiuid turbid or muddy for a short tima, and 
then ainka to the bottom. Some bodies are c^)ahle of being dis- 
solved in one kind of liquid, but not in another kind. Camphor, 
for instance, is soluble in alcohol, but insoluble in water. On the 
other hand, sea salt dissolves in water, but not in alcohoL Hence, 
if yon dissolve camphor in alcohol, and add water to the solutwn, 
the camphor reappMrg in the solid form ; and if you add aloc^ud 
to an aqueoDs solutioii (^ salt, the tatter is instantlv thiawu to 
the bottom of the liquid. Metals are soluble, but thcij' utlutitm 
only takes place wbien they am put into aoids. The operatioii 
of «alniion is more speedy in proportion as the snbsteuee to 
be dissolved presents a greater snrfece: on this principle is 
founded the practice of pounding, cutting, and otherwise divid- 
ing the bodies intended to be duuolved- The solution of a body 
invariably produces oold ; aqd advantage has bera taken of this 
phenomenon, to produce artificial oold, much greater than ths 
most rigorous temperature ever observed in any climate. If you 



IT 



SOLUTION. 



xuai, a» tuB nan uiHauive», toe vrater oecomes coia. oaiDLiou 
much aeceterated h^ he«t and witation. But whether a a 
liquid, or heat, or agitation, shonld be employed in any pniticn 
case of solution, mxiet be determined by the natore of the m 



gnup in the hand a phial of thin glass, half filled with water, 
and giadualty add to it powdered aal ammoniac, you will fliui 
that, as the salt dissolves, the water becomes cold. Solution Is 

rticolar 

stance operated upon. In making solutions, it ii necessafy to 
use B vessel of such matefiats as sbaU not be acted upon by ita 
coatentd, and of soffident edacity to admit of any Badden expan- 
sion, or frothing, to which chemical action may give rise. 

gotution is generally performed for the purpose of placing the 
substance operated upon in a state fit for chemical action. It is 
of two kinds. The first is that in which the liquid doea not act 
chemically upon the substance which is dinolved. The second 
is that in which chemical action takes place. Solutions of the 
fitat sort reproduce the original snbstance upon being evaporated, 
or boiled to dryneM, but solutions of the second scvt give & sub- 
stance altogether different. 

The fluid most generally employed as a solvent, partly be- 
cause it furnishes solutions of the first sort, principally because 
it lias a greater solvent power than any other liquid, is water. 
In certain cases, however, alcohol, ether, oils, acids, and sicaliea, 
are emploved as solvents. The solvent powers of different 
liquids wiU be investigated in subsequent sections. 

A 8ATUBATED tolution 13 oue in widch the liquid ctmtains as 
great a quantity of the solid matter as it is capable of dissolving. 
A DILUTE tohition is a mixture of a saturated solution with pure 
water. Saturation is affected by temperature. At every parti- 
cular decree of heat, a solid requires for solution a given qnantity 
of stdvent or liquid. But in proportion as the tem^^erature rises, 
the quantity of liquid requires to be lessened. This effect takes 
place to an estent, variable according to every solid, beyond 
which elevation of temperature no longer increases its solubility. 
This is a general rule, but there are some soUds upon which 
heat has no such effect, and in which the solid and the liquid it 
is dissolved in, remain in equihbrium at every temperature ; 
while there is a third class of solids, the solubility of which 
diminishes with increase of temperature. It follows from the 
above facts, that saturated solutions of salts must boil at veiy 
many different d^peee of heat, each dependent upon the quan- 
tity of salt present, and that by ascertaming the temperature of 
a boiling suine solution, its percentage of solid matter may be 
BSoertained, admitting, of course, the degrees of solubility of the 
salts under consideration, to have been previously determined. 

The student should be povided with a variety of vessels for 
paforming the operation of solutiOD, a few of which shall now be 
described. 

Foremost in the list of useful veesels for solution, whenever 
small portions for Testing are operated upon, stand bulb tubes 
■md tett tubei, such as are represented by the figures on pi^ 8. 



8 SOLUTION, 

a b 




n 




D,g,nz»-it,G00^li: 



These Bhoold be made of Geniuui potash ^aw, or hard vhite 
elasB free from lead, or of pale ^eea glass. The bulb of a and b 
ahoold be 1 ^ or 1 i mch wide, either round or peoTHsbaped. The 
neck i inch wide and 4 inches long. The subrtance of the glaaa 
^ inch thick. The moutii a little turned out, but not so much 
■mdened but that, when the tube is held near the mouth with 
the thumb and middle finger of the right band, the fore-finger 
shall be able to close the tube by simple pressure upon ttie 
mouth. The fibres show the exact size and proportions of good 
tubes. The ooist of these tubes is Is. each. 

The quantity of liquid used in one of those tubes may be balf 
the bulb full. The tube is to be eloaed by the fbre-finger soon 
after you apply heat to the bulb. It is too late to close it when 
the liquid has begun to boU. The object of closing the tube is 
to retain a oertain quantity of air abore tie liquid. This air 
becomes eondensed at the top of the tube by the steam that is 
produced below; it keeps the tube cold enough to be held by the 
fingers, and ai^TQcnts by its pressure the temperature of the 
liquid. But if you remove the &wer for a single inatant from 
the tube, the ooofiued air escapes, not ateom rushes forth, and 
the tube becomes too hot to be tield. 

Other methods of supporting tubes over lamps will be de- 
sfjribed in the section on " Supports for Apparatus." 

Tubes similar to figure c, page 8, may be sometimes used. 
The mouths of these £ould be of just such a size as to be easily 
closed by the preemre of the fbre-finger. Straight tubes of this 
narrow kind, howover.only answer for boiling, when yery small 
quantitiesjire operated upon, as, in oonaequenoe of their want of 
capacity, the heated liquor is too apt to noil over. This acci- 
dent can in a great measure be preyentod bv holding the tube 
in ft diagonal position oyer the lamp, so that tne &axae may strike 
agmnst the liquid nearer to the sur&ce than to the bottom. 

The prrasure of the fore-finger upon the mouth of the tube is, 
however, more to be relied on thtm any other contrivtmce, for 
preventing the boiling oyer of the solution. If you observe the 
precantion pointed out in the preceding paragraph, of closing 
the tube, before the liquid begins to boil, but not tQl it is just at 
the boiling point, you will retain sufficient air in the tube, to 
enable you to hold it without being incommoded by the heat, 
'^lile you keep the liquid heated up to its boiling point- 
"* Jf the tube becomes accidentally too hot to be Tet*ined by the 
fingen^ you must remove it from the lamp, suffer the boilmg to 
cease, qool tlie upper end of the tube by die exterior application 
of wet blotting paper, and then commence the boiling again, 
with the mouth of Uio tube closed by the finger. 

Very capital boiling vessels also are tubes of the some length 
and slupe as the last figure, but of greater vridth, say fbnr-fifthe 
of an inch in diameter, lliese are indeed too laree to be held 
by the band, becanse their months cannot be closed by the En-e- 
finger, but it is easy to support such vessels over the flame Qf a 



10 SoUTTtoN. 

spirit lamp ky the Utie-holtkr, of ishich I diall give a descrip- 
tKin in a aub»equent aectiiui. The prim «f these tob«8 is 3d. to 
Cd. each. 

Other useful vemeh for eolntion, in small expefktents, can be 
made of glass tubes, beddee those already described. TTw sub- 
joined diagrams exhibit the forma which may be given to each 
vessels. Figure a represents a tube about the size of a quill. 



the glass of which is about the thickness of an addrcfls-card, 
"Hie tube is closed at one end, and widened out a little at the 
other, which is open. Figure 6 Kptesents a tube of the smne 



description, ^rith a bulb blnva st the end of it, so as to consti- 
tute a BuaU matnsa. Figure c lepreeeuta a tube of the same 



SOLUTION. 1 1 

gin, is an iuBtnuneatof great utility in performing the 

operations of dipalbn, sBlution, &c. It beara the 
sudden application of heat eiceUently; but on ao 
connt of mat Ihinneu, u very liable to be broken by 
a slight blow: it therefwe reqiiirea t* be handled 
catefully. The student abomd be provided with 



I 

R ^k who Bell the empty flwks, after ha' 
wi^^V the Florence oil 
^mH^^ extremely cheap. 

The figure in the raarein i _ ^ 

much employed by the Oerman chemists. It is made of 



several of them. Thoy are to be bad of oU-men, 
who Bell the empty flwks, after having disposed ^ 
the Florence oil tney contained. Snch flasks are 

The figure in the maivin represents a sort of flask, which Is 
uch employed by the Genu — ' — "■'" " ' ' - ■' ■ 

^|v the action of heat or of acids. The bottom ia 

HI turned a little inwards, so that it con stand 

H I alone without support, and is made thin, so 

^M I that it can be e^Kised to a naked fire. The 

^fl^^L flint glass bottles sold in this ooonti^ are 

^^K/^^^^ much inferior to these continental giaaeeB. 

^^^H^^^^ Vessels of twice the size of the figure are very 

^^^n^^^^H useftil for eBecting the solution of small por- 

^^H' ^^H tions of a substance in qualitative analysis. 

HL..,^H The price of a flask of } oz. capacity is 6d., 

^^K^^^P of I oz. 9d., of i oz. Is. The smaller sorts 

^^^^B^^^ are very thin, and fit for use in delicate ex* 

periments on weighed quantities. 

The annexed figure represents a bottle extremely well 

adapted for u»e in preparing solutions. It is of 

a good shape, very thm, and quite fiat at the 

bottom, wide in the nedc, and with a broad 

smooth mouth. It c«ne to this country with a 

sample of Ga//i/>ofi Oil. Its capacity is 3 ounces 

of water; its height 5 inches. 1 have never seen 

a vessel i>etter adapted to answer the operation 

of solution on a small scale. The flasks used in 



} be had in 
Gla^ow. '> 

In general, bottles made in this connby are too thick at the 
bottom, or, if they are ordered to be blown thin, then the necks 
are made prodigiously thick, or they are too narrow to allow 
one to pourfromthe bottle with oonyenienoe,ortheyare broken 
off with so many jagged points, that you can scarce handle them 
without cutting your fingers. Most of the inconveniences hN« 
enumerated are avoided in the flint ^ass flasks now made Eor 
sale in Glasgow. 

Vessels of the same form as the three last described, but 
of greater capacity, can be employed when luger quantities of 
Iiqttid>STe to be heated. 



12 SOLtTION. 

I Bhall here deicribe the forms of flaska recommeiided by 
Bbbielidb, aa generally suited to the different opewtiona of ansr- 
lytical chemist^, and Berving, not only for boilinj; in, but as 
Kceiven to use wHh retorts in the process of diatillation. Th«y 
are represenfed in the following figures a, b, e, d. When they 
caiOS ftom the 
glBss-honse they 
Sometimes have 
long necks, (a,) 
in which state 
they answer beet 




( distillatkinw But 
\ the long neck ia 
I an binderance in 
boiling, and con- 
sequently it is 
cut off, a« shown at o, ^ A met}t<id to be hereafter described. 
Very frequently the bo^ of the tlask is made globular, as shown 
at B. This is a good enough shape for receivers, but a bad fonn 
fw flasks that are to be used in enecting solutions ; for wheneret 
the mass which is undra operation has to be taken from the 
veeeel, a portion of the solid matter sticks in the bulb near the 
shoulder or edge where the bulb touches the neck, whence it It 
often very d^cnlt to be entirely removed. This is particu- 
larly vexatious if the operation is a guantitalive ana^st>, where 
any Ioh of matter is especially to be avoided. By tar the best 
form of flask to be used in anal vtical operations is that shown by 
D. It ^onld be of very thin and uniform glass, and have the neck 
cut off as it is here figured. When it is placed upon the sand- 
bath, in use, its month should be covered with a watch glass. A 
flask of this form stands with safety on sand, even during a strong 
boiling. And wheu tha sidution m effected, the whole contents 
of the flask can be readily washed out upon the filter, Never- 



deacribed at page 11. The price of flasks of Glerman g 
the shape of fig. a, and of 2 oz. edacity, is in Glasgow, 9d, and 
of 4 oz. capacity. Is. 3d. Flasks i^ the some size, but with the 
moudis bcn^red, so that they ean be fitted with a coric, cost Is. 
and Is, 6d. each. 

Pricet o/verv l^in PHnt Qlas» Flatkt adapted for aohitim, now- 
prepared for sa\.b in Glasgow: — 

wim HOUND bottohb: — j with flat bottoms:—- 

2 i>z. % D, page 12, ... . Cd 2 oz. fig. Ti,page, 12, .... 7d 
3oz. fig.A,p. 12, longneck, 6d 3oz. thirdflg. onp. 11, . . 8d 
6 OX. fig. A, p. 12, long neck, 8d 1 8 ok. second fig. on p. II, ■ la 

None of theae have tamed lips, but all axe thin in the neck 
as well as at the bottom. *•" 




■OLUTIOX. 13 

Seoently, porcelain ressels.fbr digestion, qt aolntioo, hare 
been made at Berlin of the annexed form. The body ia shaped 
like aa.egg, but at one end there is a wide mouth nitn a spread- 
ing lip, which answers veiy welt for pour- 
itwfrom. Two sizes are made, the smaller 
1^ inch wide, and 2^ inches high, the 
lu^r 2^ inch wide, and 2j inches high. 
They stand very well in sand, or on a 
triangle, or a perforated plate, over a lamp. 
They can be closed by a watch glass dur- 
ing the operation, and be readily cleaned 
when it is over. The porcelain of which 
they are composed resists changes of heat, 
and also the action of the solvents gener- 
ally in use. These veaaels have thotiirther 
advantages of costing only a shilling, and 
being very durable. 
Two little porcelain cups are also made at Berlin, that can 
be used in digesting small portions of matter. The lesser of 
these is represented in size 
and form oy the annexed 
upper figure. The larger 
is exactly of the same fonn, 
but of the width of figure x. 
When in use, they can be 
covered by sroall capsules of 
porcelain. They si^er heat 

A -_ Bowellth&ttheycanbemade 

^ red hot without spUtting. 
They resist also, as do all the articles of Berlin porcelain, the corro- 
sive action of acids. Theprice of these littlevesselsisthregrence. 
A third vessel of Berlin porcelain that can be used in effecting 
solutions, is a capsule, with a apoat ifnd a handle, all in one 
piece. Three sizes are made: 2 inches, 2| 
j^-"*— ^ mches, and 3i inches in. diameter. These 
c:;^;::;^ i— y vesBels can be heated either on the sandbath, 
\ _ _y or on a wire triangle over a lamp, or upon 
a hot in>n plate. 
Walcb-glasHea can often be advant^eously employed when 
the solution of small portions of matter is to be effected, par- 
- ticulart^ if they are mode 
^&om vrindow guss, as flint 
' glass is not at all snitable. 
Bnt an instrument, which, 
to a great extent, supersedes 
the use of all small capsules 
of glass or porcelain, is a 
capsule of platinum, furnished with a small flat handle or ear 
of the same metal, and sometimes with a spout. The figures 
here, and at the top of the succeeding page, represent the hill 

, .. Cooglc 








s that 
th« form and the size 
1 be lupported over the 
spirit lamp by a thin ivire triaogle. 

Plstinum vesaels, however, are about 

twenty times the price of those of porce- 

\ / Uin, even when small and thin, Never- 

\ / tbelev this onUay may he made by the 

Y J student with nltiniate profit ; for the 

X ^ ^ number of glanee saved from deBtmction 

by the common employment of platinum 

veaeels is very oTeat. Qlasees frequently break, ot suffer 

eMTOsion, when neated over a liunp, either with dry matter 

or concentrated solutions. In every such case, the student 

loeee a vessel and spoils an experiment, while these accidents 

are obviated by the employment of a vessel of platinum. 

There are certain substances which cannot be put into platinum 
vesselswithoat injuring them. 1 shall enumerate these substances 
in treating of the pnqierties c^ platinum in another section. 

Solutions of small portions of salts, 
earths, metals, &c., for testing, where the 
experiments are to be on a rough mrstem, 
may be made mi slips of window glass, of 
the width of the figure a, 6, e, li, but twioe 
the leBgthr viz., 1 inch broad, and 6 inches 
long. When in nse, the glass is held flat 
by the end c, A. The substance to be 
dissolved, in aze not lar^ than a bead 
of ^ inch diameter, is placed at e, and a 
iew drops of the solvent ia put over it, as 
at/. The end a, b, of the slip of glass is 
then held above the flame of a lamp till 
the heated liquid effects the desired solu- 
tion. More liquid can be added, if neces- 
sary, by a dropping tube, to supply the 
waste caused by evaporation. 

The other parts of this figure will be 
exphuned at the article "filtration.' 

This method of making solutions on fiat 
plates of glass is, however, to be regarded 
only as the last resource of a pmched 
operator. Any kind of glass vessel that 
has sides as well as a bottom is superior 
to a flat pldte, and as small tubes can be 
bought at a penny a ^ece, flat glass has 
harSy even the merit of cheapness to 
recommend it to adoption. 



■oimoN. 15 

The iiueTtian of a ckaige into a tube ressel, aad indeed into 
sflaakofaay cibape, requires to be executed with a proper deeree 
of can. Liquids can be Teadily inserted by tneaiu of a ^^^ 
funnel, auch as ia represented in the margin. This 
7T funnel is made by Mowing a- small bnlb of half an 
inch in diameter at the end of a tabe, opening it ob 
the upper side, and bending out the edge, and finaUy 
drawing a long narrow neck oppoaite to its month. 
This neck may be-6 or8 inches long, so aa to be able 
to reach the bottom of most teat tubes, and small fla^a; 
or, it may be made only one Inch long, and b« inserted 
lor use into a straight narrow tuba of somewhat greater 
length than the vessel into which the liquid is to be 
poured. The same funnel then serves, with the addi- 
tion of 3 or 4 narrow tubes of different lengths, to pour 
liquids into all vessels that hare long narrow necks, 
such aa tubea, retorta, &c. The emelleiit uie of ^ 
teriiig funnek can also he used for this pnrpose Those of 1^ 
inch diameter are now made in Glasgow with very narrow 
oecka, in order to answer properly the purpose of fillera. They 
are more durable thmi the thin blown Ainnela. 

Powders should be weighed upon h^hiy-glazed post paper, to 
which they adhere reiy slightly. They may be pourea thence 
into a tube or ilask through a dean dry fimneh If any adheres 
to the neck of the funnel, it must he wa^ed down by means of 
distilled water from the washing bottle, an instrument to be 
deacribed hereafter. 

Another method of inserting powders, and one that is espe- 
cially useful where narrow tubes are to be used, ia as follows: 
You take a slip of highly-giaied post paper, as wide as the 
diameter of the tube. You fold this longitudinally into a sort 
of gutter, on one end of which you pla«« the powder. You 
hold the tube in an horizontal position, and insert the gutter 
into U, the end bearing the powder first. Then you hold the 
tube yertically, mouth upwards, npon which the powder falls 
to the bottom of the tube, and you withdraw the paper. 

Whatecer the form of the vessel, solution is generally first 
attempted without heat, and if unsuccessfully, the vessel is then 
placed on hot sand, or upon a wire triangle over a spirit lamp, 
or if flftt^bottomed, upon the iron plate or the wire trellis of 
the lamp furnace that ia described in a subsequent section. 

Upon first heating a bottle, it often becomea wet externally. 
This wet ia to be wiped off before placing the bottle iipon the 
hot iron plate, otherwise the bottle is liable to crack. The hot* 
tie should he waved backwards and forwards over the flame of 
the lamp, then be wiped dry, and again waved over the flame, 
till no more moisture appears. ' After this, it may be exposed to 
the fiill heat of the flame without danger of craokiag, provided 
the bottom be not too thick. 



I , Google 



by boiling vegetable or animid Habstances in water. A c< 
Teceipt is one ounce of the solid matter to a pint of water, and 
the whole boiled down, till the solution, after filtration, measures 
half a pint. Powerful Bubstances require more water. When 
a decoction of this sort 'a boiled down to the consistence of honey, 
it gets the name of an extract. 

LixiviATioN is used for separating inch mbfltanceB aa are boIu' 
ble in water fiom such as are insoluble. Buppose, for example, 
it is required to separate the tand &om a mixture of sand and 
salt: the compound body is placed in water; the salt la dissolved 
by the water; the sand is diffused through it. The mixture is 
filtered; the salt passes through with the water; the Band re- 
mains on the filter. The apparatus used m filtration, with the 
addition of a jug, is all that is required for this operation. 

Infcsion is performed when a hot liquor is poured upon a sub- 
stance that is partly soluble and partly insoluble, in order to 
extract something from it. The making of tea is an instance of 
the performance of this operation. 

DioEBTioN. — This operation coDsista in soalcing, for a long time, 
a solid substance in a liquid kept constantly hot. 

Macebation. — The continued steeping of a solid body in a cold 
liquid. Ink is produced by macerating the materials of which 
it is composed. 

EXERCISES ON SOLUTION. 

matt qiKDtil; 
. . d aulpbiM oi ... _ . ... _..__...,. 
id obicrve tli« diSerence in tliCKilubilit]' of tb«M eompouu 

2- Alake a mtitnr* of lUrch. taoA, lugari uid ch&lk. Put thu iuta cold 
water, fitatt the niiituie, ud filter. The mid liquor will caaMio tbx 
■uj^nr. Boil the wlid miCter in freah water, in ■ porcdiia cipiuU. Tbe 
hot water wiQ diootve tbe itirch, which ma^ be waih«d vitaj. After 
filtration, add muruitie add to the sdid masa, to dinolve and TCmaic the 
chalk. The land will then remain alone. 

a Boil fam maitic in alcohol, in a g\tm tube, eloaing the month of the 
tube with the fincer before applvinf heat to the tube, to pTorlace an elevated 
temperature. The reaullinE lolution, Jaigel; diluted with alcohol, i) a 
good waih to fix pencil or cbtJk ditvinKi. 

4. Dissolve a grain of copper in lix drops of nitric acid, oaiDfr a tube of 
the form b, page 10. Ohtene the effervescence that is produi^ed j the pro 
ductJoB of red gat just abo4e the liquor, the change of the liquor to gnen, 
the heat which it produced, the peculiar smell that ia disengaged. In one 
minute the copper will be all dioolved, the liquor remainiDf; green. Blow 
ai7 into the tube by a smAller tube held in the mouth. This eipets the red 
gas, sad turns the (^reen liquor blue. ' Alternatelj shake the tulw and blow 
air into it, until the greea colour and red gas no tnore return. The smell 
l[oei away with the gas. Look into the tube, and Dot ocroit it, to see the 
colour of the liquor and gaa. Next boil the liquor over a spirit lamp. 
White fumes of nitrio acid go away. When theliquor gets thick and pastf, 
allow it to coo). It will fiwm a mass of blue crystals, proceeding '' 

fromacentre. This i. "i<-~" "f ~ in..i_i..... .1.. — ., 

melt, get drier, an<l 



APPLlCaTIOK or HBAT. 17 

The ult noiv Hfcompnaa, ml ■ ■troDE amall tf nitric icid it dimingad. 
Wh>n tbe bulb ia cold, half fill it ivilh water. Part of tbt faud mitMr 
dSnolvH, producinj; a blua aolutien of nilrtM (rf copper; part remuoa an- 
diwolnd u t. hlniik grcto powder, Thii iaanitTitc of eopptr with eirwa 
of baK, vhirk ii in«luhlF in wst«r. Add a lingle drop of nltrir arid 
and tha irbolt will dimlT*. To the nmlting lolutioD, yoa eta apply the 
diSenat tttU &r Kipper- 



APPLICATION OF HEAT. 

Thh application of heat has been eo ottea prescribed in the pre- 
ceding article, that it is Ttetxeeaiy to take the earliest opportu- 
nity of describing the means by which different high tempert^ 



tnrea can be produced and readily applied to th'e object of 
ej^riment. 1 therefore take up thia subject next in order. 

The method of applyinghest differs accordingto the intensity 
of the heat required, to the bnlk of the object to bo heated, and 
the length of time during which the heat la to be anatained. It 
can be conveniently applied by means of a amalt spirit lamp, a 
large spirit lamp, an oil lamp, a gas flame, a Bmall charcoal 
fire, a blow-pipe, or a powerful fiimace. 

SMALL SPIEIT LAMPS. 
When you wish to apply a moderate heat, to erapomte a 
solution of smell buUc, to heat the contents of a glaea tube, or to 

r'te a atnall crucible, you Tnake usp 
small spirit lamp. This consists of 
a short strong glas bottle, the neck of 
which contains a braes or tin plate tube, 
holdmg a cotton wick. The bottle 
■hould be dearly full of spirit of wine 
of a moderate strengtii, 
''■' ' ' okes;n'tooi 

e powerful than it ought 
to be. The specific gravity ahonld not 
be above 0.86^, nor under 0.84. Spirit 
of wine of the proper kind bums with- 
out smoke, so that a tube does not become soiled when heated 
in the flame of snch a lamp. This is of considcrabie importance, 
for when a tube becomes coated with soot, as it does when you 
hold it over a candle, you cannot see what takes place within it 
during an operation. The lamp should be furnished with a 
glass cap fitted to it by grinding, to prevent the evaporadon of 
tiie spirit when the lamp is not in use. When you want to put 
out the flame, you clap on this cap as an extinguisher. 

Berzelius recommends the wick holder of such a lamp to be 

made of silver or of tin plate, and not of braes, as the latter is 

acted upon by the spirit, and partly carried np and depouted as 

soot upon objects h^ted in the flmne. He also recommends the 

b3 




IS APPUCATtOM OF BBAT. 

metallic wick holder not to be fixed m'fAin the neck of the bottle 
but around it, to prerent lactate by expandon when heated. — 
The prices of glass spirit lamps, with bran wick lu^den, and of 
the abore figure, are— 

2 OS. c^Mcity, .... 2a. ed. 



Or with a pore silver wick holder, 4 oz. capadty, price fls. 

The annexed ligare represents a cheap and convenient Jamp 
for small experiments. It is made of japanned tin plate, 2^ 
inches wide, and 1 inch hieh, excluHive of the neck, which cou- 

O tains a tm tube one-fifth of an inch wide for 
the wick. It is ptoYided with a tin cover made 
to fit the neck as close as posible. 

This amall lamp servea either to bum oH or 
ipirit, except that fi)r these two liquids a dif- 
J fereot species of wick holder h required. As 
'' "J represented here, the lamp is adapted 
^ _.- oil, beinfffiirnished with a very short tube, 
and having noles both ifi the tube and in the 
horizontal piece of tin to which it is attached, 
intended to ^cDitate the pre^nire of the air upon the surface of 
the oil, so as to make it rise in the wick. When such a wide 
holder is used with spirit, there proves to be too free a commu- 
nication between the spirit in the lamp and the external air, and 
the consequence is, that as soon as the lamp has been lighted a 
little while, and the tin has got warm, the spirit takes fire at the 
month of the lamp, or at the holes in the wick holder, and hums 
there as well as at the top of the wick. The wa; to prevent 
this, is to have a wick holder of the following description, namely, 
^—^ ft tin tube, two inches long, and one-fiiUi of an 

inch wide, with an horizontal resting plate, 
three quarters of an inch in diameter, fixed 
across its centre, ailhoiit air Meg, either in 
the plate, or the tube, and with s good cork 
fixed below the plate, and adapted to the 
mouth of the lamp. This closes the lamp 
nearly air-tight, raises the flame conraderably 
above the mass of spirit below, and yet does not 
prevent the rising of as much spirit as is de. 
manded for the sustenance of the flame at the 
wick. The cover of the lamp requires, of 
couise, to be made deep in proportion to the 
length of the wick holder. It must grasp the 
necK of the lamp below the cork. A wick 
holder of this description can be used to con- 
vert any flat broad bottle int« a temporaiy 
spirit lamp. The little ink bottles sold by the 
Stationers under the name of thumb-ink*, and 
which are very cheap, con be used as spirit lamps. By cluuiging 




APPLICATION OF BRAT. 1 9 

the cork, it can be adApted to either a naiTOw-mouthed or a 
■wi<ie-in<nithed Teggel. You increase or diminiah the power of 
the Bpirit lamp, by making the wick thicker or thinner. It ia 
usefiil to have one or two spare tubea of differeat diameterB. If 
yon cannot conveniently procure them of tin plate, you can 
easily substitute a bit of glass tube pa^ed througli a cork. Tile 
price of the japanned lamps above described is Is. each. 

Another and very cheap variety of small spirit lamp, will l)e 
described presently. It is made of clay, and forms part of the 
lamp fiimace. 

LARGE SPIRIT LAMPS- 

ExPEBTHBHTs wliich require a 
p'eat degree of heat, such ns the 
Ignition of refractory substances, 
and the decomposition of minerals 
by fusion with alcaline carbon- 
ates, demand the assistance of the 
spirit lamp with circular miek or 
double current of air. This is 
one «f the moat indispensable in- 
struments of the analytical chem- 
ist, for there are many accurate 
experiments which cannot be per- 
formed without it. This lamp ia 
represented in a complete state in 
[ the adjoining figure. It is com- 
monly made of brass, but some- 
times of japanned tin plate. Its 
most important parts are as follows: — 

The wick e passes between two cylinders which arc eon- 
t£ flH| nected below by an horizontal plate, and it can 

^ I^P _ be raised or depressed by means of the toothed 
■Hj^^^H^fc wheel e, and the toothed bar g. The lower end 
^^^^^^W of the latter is connected with a cross bar o, 
HS^H upon the end of whidi a ring is fastened, on 

which ring the wick is stuck. The cross-bar and toothed rod 
work up and down in the box b. In some lamps the wheel and 
bar e 9 are omitted, the wick holder being constructed like 
those of sinumbra lamps. The box b does not form part of the 
spirit holder a a, as it does in common lamps, but 
is separated from it by the open spaces / /, or nt 
any rate by a partition on each side. The sphit 
passes from a a into b through the pipe k, whioli 
forms the only communication between the spirit 
holder and the box which holds the wick. The object of this 
(Wntrivance is to prevent the explosion which frequently takrs 
]ilace when the common spirit lamps are inflamed, and which is 
owing to the inflammation of the mixture of atmospheric air 
and vapour of alcohol which forms in the spirit holder a a. At 




APnJCAIION or HSAT. 

t is an i^ening bv which the spirit is poared 
into tlie lamp. Tois is afl^rwaras closed by a 
cork, or a icrew. A piece of glass is cemented 
' in tiie front of the lamp, at (, to afford an np- 
portunity of readily ascertaining how much 
spirit the spirit holder a contains. The lamp 
is provided with an iron chunney, !, By raising or depressing 
the wick, the flame is increased or diminished. The air is brought 
to the spirit, eitemally by the side, and intemaUy by the ctmal 
i. The wick must be cut quite level, and must never remain 
in a charred state. When a lamp is constracted in this manner, 
and according to the following scale: 

1 Foot. 

it affords heat sufficient to fuse 360 groins of carbonate of soda 
in about fifteen minutes, supposing the saJt to be contained in a 
platinum crucible of the weight of from 300 to 380 grains, and 
lai^ enough to cwitwn an equal weight of water. A lamp 
which is. incapable of effecting the fusion of at least 180 grains 
of carbonate of soda, though useful in a great many experimenta, 
is not powerfiil enough to be generally employed in the analysis 
of minerals. The experimental chemist ought to possess two 
lamps of this description; one for fusing, and another for other 
experiments. In the latter case, the rods which support the 
lamp may be strong, but for the fusing lamp, the rods must be 
maiie as thin as possible, in order that they may not carry away 
too much of the neat. 

Some improvements have recently been made upon this lamp, 
which are not shown in the above figures. The first is a hinge 
for the chimney, upon wliich it is fixed in such a manner as 
to he readily turned upon or Jrom the flame. The second is a 
hinged door which closes the mouth of the wick holder when 
the flame is extinguished- The tlkird improvement consists in 
the apphcation of a sort of dome or jacket, to protect a heated 
crucible from the free air. 1 shaU describe it in the article 
" Ignitbn." 

The cost of this kind of lamp, complete, with stand and 
rings, and well finished, is about 25s. A powerful lamp with 
feet, made in Germany for the use of apothecaries, costs 31b. 6d. 

With a lamp such as I have described, all gradea of heat can 
be obtained, from that which keeps a liquid gently digestine 
without boilin?, and which is produced by depressing the wick 
till it gives only a small blue rmg of flame, upto the heat which 
is sufficient to melt a small silver crucible. The applications of 
this lamp are therefore so extensive, that it becomes an indispen- 
sable instrument to every one purposing to undertake sJiytning 
like a course of effective experiments. In a vast number of 
oases, it prevents the necessity of employing fumseea; for it 
affords sufficient heat even for the decomposition of many 
minerab by fusion with carbonated alcalies in pretty largo pla- 
tinum crucibles, and for effecting many other results, which, 



APPLICATION OP HBAT. 



In France and Qermany, spirit of wine is very cheap, but in 
England it is veiy dear, in consequence of the excise duty. This 
is an nnfoitimate restriction upon the induatrioua pursuit of 
analytical chemistry by Englisn students. Many who have 
more zeal than money, attempt to pertbrm imperfectly with oil- 
lamps, what foreign chemists perform perfectly with spirit lamps. 
This must continue to be the caae until an alteration takes 
place in the excise laws. There is no doubt that the pn^ress 
of experimental chemistry is retarded in this country by the 
simple circumstance jast alluded to. 

In consequence of the deamess of spirit of wine, a liquor sold 
under the names of acetic naphtha and pjroxilic niirit, and 
which is a secondary product obtained in the manufcctnre of 
vinegar from wood, is frequently made use of. It answers the 
purpose of combustion very well, and is cheaper than spirit of 
wine ; but it diffuses in the apartment where it is used a very 
atroDg and (to me at least) disagreeable smell. It has also the 
property of q)eedily rotting cork, and therefore of loosening the 
wicK holders of the small lamps described above. And finally, 
when used in a large copper lamp, it soon destroys the cotton 
wick. For these reaaonti, J recommend spirit of wine in pre- 
ference to pyroxilic spirit. 

OIL LAMPS. 
Oit lamps are in general only employed when yon require a 
feeble but long-continued heat, and for this purpose the best sort 
of Itunp is of the simple kind described at page 1 8, without chim- 
ney or central air pipe. The argand lamp is, 
however, sometimes recommended as nsefiu in 
chemical experiments, and is made for sale of 
the form shown in the annexed figure, and 
provided with a copper chimney. But the 
operations are very few in which these lamps 
"^e really useful. For evaporations and diges- 
._Qns they give too much heat, and for ignitions 
by far too Uttle. For operations that require 
a strong heat, they are replaced by the large 
spirit iMnp which I have just desmbed, and 
for other operations that require less heat, hy the smaller spirit 
and oil lamps, 

I have already described a small lamp adapted for burning 
oil. I now subjoin a description of another lamp employed for 
the same purpose by Behzkliub. 

The form of oil lamp which, he says, " I have found to be 
most convenient for chemical eipeiimenta," is depicted in the* 
margin. It is broad and low, and on that account boms to the 
end without any diminution of flame proceedii^ from scantiness 




AWUCATION OF HUT. 




of oil. There IB no 
want of draught. 
The wick o 6 is 
flat and bcoad, w 
that the lamp gives 
a^oodlight. The 
viclc holder is sol- ' 
deredtoafiat plate 
which can be {aat- 
encd in the neck 



ef. A ring of leather between the sorewa closes the mouth 
tight, BO that no oil can escape when the tunp is turned about 
in various poaitioDB, or even when it foils to the ground. Such 
a lamp is very oaeAil at night, to give light at any particular 
part where a person is filtering or carryiiu; on any other opera- 
tion, in a place not sufficiently lighted by the ordinary illumina- 
tion of the apartment. 

You have to observe, in relation to an oil lamp, that when it 
deposits soot on the vessel placed above it, there is scarcely any 
heat transmitted. You must, therefore, pull up the wick only so 
&r as allows the lamp to bum without smoke. If you have 
good oil, a tamp of the sort now described will horn for hours 
' gether without needing snuffing, a circumstance of consider- 



toget 
able 



Currents of ur in an apartment, proceeding from open doors, 
or from the movements of the experimcnlco', hinder a lamp from 
burning with a stea^ and even flame. This can be remedied 
by placing a small chiinney over the flame, for the support of 
which chimney, the ring B is employed. The ring id tilled 
with holes to admit air. It has a top with a cu'cular hole 
in its centre j A, rether larger than tlie riuK e/of the lamp A. 
Below, it has three feet, f i, by which it is held steadily on the 
lamp. When this ring is placed on the lamp, the air for the 
support of the flame passes through the ring of holes, and presses 
towards the wick, between 2 h and ef. A short cylinder, either 
of metal or of glass, such as a piece of a retort neck, is placed 
over the flame, and. so as t^i rest upon the upper plate of the 
ring. The length and width of such a chimney can be varied 
according to drcumstanoes. — Thus far Berzelius. 

I find that if a cotton wide, which is to be used in an oil lamp, 
is first soaked in strong vinegar, and then dried, before insertion 
in the oil, the crusting of the wick, and the consequent necessity 
for frequent snuffing, is entirety prevented. Those who use 
■inumbra lamps for domeetio purposes will find this practice to 
be worth their attention. 

The oil called droopmgt of ticeet oil, is the kind that is best 
adapted for chemical lamps. 



ao,«-.^i h, Google 



GAS. 

A coNSiDEBAHi^ DDrober of experiments requiring only a 
modeiste degree of beat, and a good many also of those which 
Ter[uire a high, but not an intense, degree of heat, caa be exe- 
cuted by those who have command otgM, without the use of 
any other fuel. It is convenient, where it is possible, to have 
the gas pipe come from below, up to, and terminate at, the sur- 
&ce of a table, so that burners of different kinds, such as a 
ainiple jet, or a powerful argand, or a blow-pipe nozzle, can b© 
screwed on or off as required. Where it is not poeeible t« have 
the gas pipe fixed in such aposition, the next best arrangement 
is to have a flexible tube affixed to the pipe, with a temunation 
adsfited to teet steadily on the table at any required spot, and 
to receive burners of the above-mentioned varieties. I shall 
give a description of such an apparatus in a subsequent chapter, 

I should mentioQ in this place, for the information of teachers 
who may be induced to give lessons on practical chemistry to 
larre numbers of persons at once — for example, to the members 
of Mechanics' Institutions, or to other classes of students — that 
a convenient method of substituting gas for spirit-lamps has 
been pointed out by Dr Beid of Edinburgh. 

A long plank, a toot broad, and two inches thick, is supported 
hOTiEontslly at about three feet above the floor. A gag pipe is 
fixed i^n the centre of the upper side of this plank, ana runs 
its whole length. At fifteen or eighteen inch^' distance from 
each other, there are upright jets arising from this gas pipe, the 
whole of which are nuder the control of the teacher, who stands 
at one Mid of the plank, where there is a stop cock to regulate 
the issue of the gas. 



» £ g 2 g i_ 

5 T 5 5 D 



A B C D represents the npper snr&oe of the plank. P is the 
gas pipe nmning down its centre, yjjpy represent the jets oi 
gas. T is the podtiou of the teacher, who is able to see every 
tiling that is teansacted the whole length of the board. Tlie 
pupila who are to he exercised in experimenting, stand on each 
side of the board, one opposite to each gas light, as shown by the 
nainben 1, 2, 3, 4, 6. 

*When the numlier of pupils is considerable, it is neceam^ to 
use two planks instead of one. In this case, they should be 
placed so as to converge where the teat^r stands, and present 
the sh^ of the letter V. 

I shall, in a subsequent section of this wvi^ present a course 
of elementary experiments adapted to be execnted by a Urge 
dasB of students, superintended upon this system. 

Moat of the experiments that are commonly perfonned over 

..HOgIc 



24 



APPLICATION OF BKAT. 



the small oil lamp, and small ^irit lamp, can be made over the 
ees flame ; but it is not possible, by any form <^ burner yet 
introduced, to effect with gas those fasioDa and decompoations 
for which the lar^ spirit lamp is recommended. There is a 
want of intenaitjr m the heat of the ras flame, which renders it 
inadeqaate to tluB end. Consequently the lai^ spirit lamp is 
valuable even where the operator has command of gas ; and it is 
still more valuable where, as in Glasgow, it is diiEcult and ex- 
pensive to procure charcoal for furnace operations. 

LAMP FURNACE. 
I GIVE ttus n>pellation to a set of apparatus adapted to expose 
vessels of difiereut sizes and shapes, in a convenient manner to 
the heat of a small flame, produced by niiiit, oil, or gas. A 
section of the chief parts of this ^paratus is shown in the mar- 
gin, as connected for use; but the articles belonging to it alto- 
gether amount to eight, and are as follows: 
1. A eglind^, open at both end», five inches long, and four 
inches wide, with a double row of 
boles round it, each hole being 
half an inch in diameter, and half 
an inch apart from the others, and 
each row of holea half an inch di». 
tant from the end of the cylinder. 
Letter b in the above figure, 
shows a section of this cylinder, 
and the annexed outline repre- 
sents it in perspective. Hie ma- 
terial of which it is made is salt 
glazed fireatone, of about the fifth 
of an inch in tluckneas. 




is made of salt glazed firestone. It is of a lonnd form, 3 inches 
wide, 2 inches nigh to the shoulder, and 3 inches to the top of 
the wick holder. The latter is made of tin plate, in the man- 
ner of the wick holder represented at page 18, It is depicted in 
the above cut, as being slightly conical, which is the form given 
to the wick holders of small spirit lamps by the German che- 
mists, but I do not find it to be better than the cylindrical wick 
holder. This ^irit lamp is provided with a cover, made of fire 




APPUCATION OF HBAT. 25 

clay, and of the form ahown by figure a mm !?■ The inade 
of this cover is scljusted to tlie neck of the lamp by being: 
lined ffith paated pwer. The wick holder ia kq>t in the middle 
of the neck by a cork fixed upon the tnbe under the flat plate, 
but not represented in the ent. 

III. A flat ring, of the figure shown in sectioil 
by e e in the first figure, and shown by the out* 
V Ime in the margia as when seen from above. 
\ It ia made of salt-glBEed firestone, ia 6 inches in 
J diameter, aitd haa in the middle a hole 3 inches 
/ in diameter. It ia | inch thick, and has on the 
under ude a projection shewn by e c, which 
seiT«s to fix it on the cylinder 6 in the same 
manner m we fix on the lid of an ear^enware tea-pot. The 
hole in the middle of the riw ia rather wider above thui it ia 
below, the aides being cut adant that they may the better fit 
the round bottoms of naaka and capaulen. 
> IV. A iome, repreeented in section by d in the firgt figure. 
It ia made of laltf lazed firestone, ia i mchee high, 3^ inches 
wide at the bottom, and 1^ inch at the top, open at both ends, 
and I of an inch in thickness. 

Theae four artieleB are aold in a aet for one shilling and six- 
pence, complete as exhibited Mr the first cnt, with the excep- 
tion of the fiaak marked e. In circumstances, where it may 
ht^pen that this flrestone apparatus cannot be procnred, you 
may supply ita place by similar articlea made of tin plate, which 
however, are leas durable in consequence of their liability to 
suffer &om rust, and at the same time cost twice the price of t he 
fireatone. The cylinder when made of tin plate should be 
strenffthened by a strong wire soldered round each extremity. 
The lamp may be suppued by the glaaa or tin lamp formerly 
described, or 1^ a jet of gaa. The flat ring can be replaced by 
a perforated tin plate, 6 inches diameter, either round or square : 
the former ia penupa the neater shape, but in actual operations, 
the. comers of the square plates are not ueeleas; since being 
generally cooler than the rest of the plate, they serve as handles 
by which the plates can, if requisite, be lined and removed. 
'Die dome may be supplied by a truncated cone of tin plate, 
4 inches high, 4 indi» wide at the bottom, and li inch wide at 
the top, ao as to resemble a fimnel waiting its neck. 

I proceed to desoribe the other portions of the lamp furnace. 

y. A piec« qf thiek tin plaU, 6 mchee square, the price 2d. 

VI. A piece qf iron teu-e Ireliit, S inches square, the price of 
it, 4d. The size of the wire and the mesbee arc the same as 
shown by fig. A. In the event of your finding it diificult ta procure 
wire trellia of the d^f^ree of fineneaa ahown by figure A, which 
is, hovrever, now easy to be got in most large towns, you can at 
all ey&ata readily eonetruct a substitute for the trellis, by knit- 
ting iron wires of the thirtieth of an inch in thickneaa int« the . 
form ahown by the figure B. (See the figures on page 26.) 



k; 



APPLICATION or HEAT. 

Fig. A. Fig. B. 



VII. A pan of tin plaie, 6 iaeiita in ^ame^tyOoA I iaciiAeep. 
It may be round, square, at oblong, but it miut be Ibnned of 
one piec« of metal, with tiie edges tomed up, and beat together 
at tne eoraere, so as to be tiffht without solder. The pric« of 
Bucb a pan is 6d. or 8d. A ^lollow cuMole of tin plat« or cop- 
~ ~ S inebea in dismetw, and 1^ inch deep, answeta the porpoae 

er, and only cofrte a few p^ce moie. 

VIII. A Mangle of iron mfi of tbe subjraned fimn, nutde 
of wire not exceednig A of aa inch in thkknew. Thera 
shoold be several aizeg of this artick, in 

which the length of the sides of the tri- 



be just long euoueh t« reet steadily 
the flat ring (III.) when ^e trian^e is 
placed over the centre of the peiforatkMi 
in the ring. 

Vte q/* Qte Lamp Pomaoe. — Such is the Lamp FnnUKe. I 
proceed next lo describe its nses. 

a. To boil in a fta*k, Ike hottom of vihiek is nmnd, and the 
middle of akieh i* 3 incAe« in diamtter: — Put the cylinder 
amund the lamp, place on it ih« flat ring, fix the fiask in th» 
hole of the ring, and cover it wHh the dome. The c;rii^^^' 
keeps the flame of the lamp steady by protecting it &om cur- 
rents of air, and it sapports the ring, the ring supports the flask, 
the dome retuns the neat conununicated to the flask, keeps the 
cold air from it, and thereby eonaderably increases the heating 
power of the lamp. It thus uuwers in some respects the pur- 
poses of the dome of a reverbeTatmy furnace. When the Jacket 
IS of tin, it should be kept bright. — Four ounces of water con- 
tained in a Florence flask, placed oven this anall lamp, boils in 
less than five minutes. Henoe this furnace eflbrds as great a 
degree of heat as is required by a student in making solutions of 
most salts for qualiUitive analysis. A much greater qnontity of 
a liquid can be boiled within a nven time over a spirit fl^e, 
with the aid of this apparatus, ^an when the same flame is 
employed in the Mien air, and tiie vessel suspended over it by a 
retOTt holder; ana consequently, a given quantity of a liquid 
con be boiled with a less consumption of spirit with this appara- 




APPLICATION OP BXAT. 27 

tus tlititi whhoui it. There axe, therefore, two objects gained 
by Oiling this ^poratiu — tlie operatiron is qnickened, wHle oa 
expenmTe fuel is ucanomized. 

b. To boil in a fla»k, the bottom qf vhieh it routtd and tht 
middie Ie*$ than 3 i'iutAm in diarnWm'.— When the vmbcI is of 
mutller diameter than the perfbntion in the flat ring, [t ia neoeo- 
sary \a sapport it by meana of a nnall triangle of thin Inrnwira, 
(article Vlll.) placed across the h«le in the ring, or an extra 
flat ring of pottery, with a hole I j inch in diameter. 

e. To boil tn a fiatk with a flat bellom (ttuAi aa those diown 
at page II.) Instead of umng the fiat ring, yon cover the cylin- 
der with the iron trellis (VI.], or wi& the tin plate (V.) The 
former ^en a quick heat, and the latter when a moderate heat, 
kreqnired. 

4. In etmparation. When yon denre to confine the heat of 
the lamp ctuefiy to the bottom of a c^)sule, as in ev^MrotioB, 
performed to concentrate a solution for raystallisotioQ, you use 
the flat ring. For pnrposeB of this sort, you can sapply yoniself 
with extra tin plates having holes of different dianietera to soil 
c^)(niles of ^fierent aisee; oat a hole of 8 inches diamet«i will 
admit four capsules of mzea much employed in small erapora- 
tiona ; namely, the Berlin poroet^n capsules with tamed ed^ei, 
wbidi mettfure respectirely 3^, 8^, 3^, and 4 inches in oia- 
meter. 

If yon deare the capsnle to be exposed to a more eentle and 
general heat, you employ the flat tm plate (V.) which affWs 
a heat very useful in gentle evapotations, wid can be advanta- 
geously employed with the small oil lamp. 

e. To evaporate, or to dry, by a wafer bath. — In the article 
on " Evf^ration, I eiiBll describe a small water batll, adapted 
to be used with the cylinder of this Lamp Furnace. 

/. H> ew^torate by a land baUt — When an operation requires 
the application of a sand heat, aa in some distillations, tmd in 
the evaporation of solutions for crystal- 
lisation, you place upon the cylinder 
the pan (VII,) filled with sea sand, pre- 
vioudy WMhed to ftee it from dost, and 



l- aifted to free it from stones. If oppor- 
^ ' tonity offetB, the sand may be heatMl 



heated 



spirit Annexed is a figure of the I«mp 
FunuKC with a sand bath in operation, 
c is the cylinder, and a the sand bath. 
g. Toewiporate,or t»dry,hs a i:arrtntofhQtair.~~V^ii.ea.ti» 
lamp is lighted and the apparatus put tt^ether as shown at page 
24, the flttdc « being omitted, there passes front Ute umtei end of 
the dome a rapid and regnlar current of hot air, which you can 
lead in any direction by a bent tin pipe, or which you can often 



28 APPWCATION OF HBAT. 

adrantageously tue hy placing a second cylinder and flat ring 
upon tbe top of the first, retauung the dome within the second 
cylinder, and placing the Tesael that is to be heated upon the 
upper flat ring. 

A. Jgnition. — When a small crucible or porceltun cup requires 
to be mode red hot, it ^ould be fixed at the point of the spirit 
flame, supported by a \ery thin iron wire triangle (VIII.) placed 
scToas the hole in the flat ring, and surmounted by the dome. 

Other applications of the Lamp Furnace will be pointed out 
as I dwcrilie the operations that require the assistance of heat. 

FURNACES. 

When you want to ignite a laive crucible, or to evaporate a 

large bulk of liqnid, or for any o^er purpose to apply heat over 

an extenure siu&ce, it is best to employ a chanwal fire, con- 

tajnOd in s chauffer, or fiimace of iron plate. 

The CHAvrPEH. — The figure represents a farnace constructed 

^m the following scale : { 1 Foot.) 

A grate (represented by the lower 

figure on the left hand) is fixed 

near the bottom of the furnace, and 

the whole is supported on three 

short feet to permit air to enter 

below the grate. Holes may be 

y^also pierced round the lower end of 

e nimace between the feet and 

grate. The funnel-shaped Tessel is 

formed of iron plate, and serves, 

when placed over the fiimace, to 

make the fire bum fiercely. The 

handle is of wood, fixed on an iron 

fork. You should be provided 

with a round flat grating made 

_ . 1 wire, vrith meshea i ofan inch in ditmieter, which 

. D being placed upon the funiace serves to support flicks and 

capsules whkh may be exposed to the fire. You should also 

possess several round flat pieces of iron plate rather larger than 

the top of the fiimace, with holes in the middle from iX inch to 

£ inches in. diameter, adapted to receive capsules and other ve»- 

sels to be heated. — See the perforated plates, p^es 24, 28. 

When you wish to have a gand bath, place upon the above 
furnace a pan of plate iron, 12 indies square and 2 inches deep, 
half filled with ^^shed and sifted sea sand. A chimney must 

Cnp through the sand pan, or a couple of iron bars be placed 
reen the pan and the top of the furnace, otherwise the fire 
will not bum well. 

A chauffer of another form is described in " Ede's Praetiaal 
FaeU in Chemistry" Its shape is an inverted truncated cone ; 
its dimenaons, 6 inches diameter at the opper (broad) end, and 




Ik 



APPLtunoN or BULf . S9 

2 uichn diuueter at the bottom, wbera tbere is a grate; tht 
depth from the top to the g»t« ta 3 inchea. The aide* are 
pinced with numeroue hol«a half an inch wide. It h made of 
Iron plat«, and ia mpported on an iron ring, suimountlii^ three 
iioaUga. 

The eharcoal iwed for these fumaoea ihoold b« in imall pieces, 
not larg«i than a cubic inoh, and &ee from dtuL 

When mnali fomaeea »e uaed upon taMes, they abotUd be 
placed a|Kin a pretty lai^ iron pan, supported by one or tvo 
tier <rf bncka. If tlua be not attended to, the beat, or tiie Galling 
aah^s, may set the table on fire. 

hvata^B umvEMAi. mrtablb fukkaok. — Among the rarieties of 
fiimacee adi^ited for producing high degrees of neat, one of the 
best is that contrived by ImAme of Berlm. It ia prepartd of 
MroDg plate iron, and is represented in the following figures. 
ab c d JB the iron 
envelope, npon the 
upper end of which 
is a flat rim of iron 
of the width of the 
mass of fire clay 
with which the iron 
cylinder ia lined. 
g and k ore doors ; 
jT, the aah pit door, 
» provided with a 
small central door, 
which can be opmed or closed at pleasnre. * « are two round 
openings ojniosite to each other, and intended to afford passage 
6>T a tube. These openings c«n be dosed by the two little doorv 
that are represented in the section as standing open, but provided 
with clay pluga to stop up the holes when they are shut. The 
adjoining figure shows the furnace as seen 
from above. The paiallel lines in the cen- 
-. tre repreaent the grate. At e e e there ore 
> three aoa knobs which project a little way 
^ beyond the fireclay 
■^ and serve aa supports 
' r kettles, &c., that 
3 smaller than the 
Opening of the Aimaee. 
These knobs are not 
seen in thia figure, but ore shown in the figure 
above. The three flat platea ddd serve i - 
the other band to support vessels that a 
larger than the mouth of the timiace. . 
both caaes, therefore, the vessel is aupported 
without impeding the draught of the furnace. ] 
The next figure represents the dome, with its 







30 apfucation o* bbat. 

chinimey. The dame, like the Aunaoe, is lined with firecky, 
and is provided vith a door, which also is lined with fireclay. 

QWhen the furoace is to be employed in a dw- 
tillation, it is finrt raised by means of an iron 
riBB: of the form exhibited in the mtugin, and 
which is exactly adapted lo a i, the upper 
part of the furnace. Upon this ring the eand 
bath is placed. This has a very peculiar form, 
and is represented by the two figures below, whereof the one on 

the right hand is a view 

irma aboTe, and that 
on the left sperspec- 
1 tiveview, llieneck 
of this sand bath fits 
I into the ring above 
figured, so as to leave 
Bspace between them. 
There is an opening 
on the side, i, adapted to receive the neck of the retort, the body 
of which rests in the sand. There are openings on the Diargm 
of the sand bath to admit the escape of air from the Aimace, and 
thas keep up the draught, and .this can be further regulated by 
the covers for these openings, k kk k. By means of these doors 
the heat can be increased or diminished at plessure. Distillation 
by retorts placed in this sand bath, proceeds with regolarily and 
certainty, as the operator, by means of this power of regulatiDg 
the draught, added to that of properly administering the fuel, 
has the intensity of the heat compIet«dy under control. There 
should be a spedes of conchoidal cover of iron plate made to fit 
the top of this sand bath, and having a piece cut ont of one side 
t0_pemiit the egress of the retort neck. The object of putting 
. this over the sand bath is to prevent the cooling of the body of 
the retort by too tree on exposure of it to atmospheric air. ' 

Finally, tnis figure exhibits s section of a sand bath with a 
large sunace, adapted for the same fomace, and useful in evapo- 
ration, digestion, and other 
similar operations. The 
draught is regulated by the 
' openings and lids, k k, of 
which there are ibur in the 
circumference. 

The price of a furnace of this deacription in Glasgow, with the 
deep sand pot and dome, but without the flat sand pan, or the 
opening « x, is ^. The intenial diameter of the furpaoe at 
this pnce is 6 inches. 

Wind Formacg. — I shall now describe a furnace which is 
employed for fUdon, distillation, roasting of ores, and other 
operations that require a very high temperature. It is called a 
wind furnace. This apparatus is altogether indispensable for 



AFrLICATION OF HXAT. 



many important chemical operations, although not necessat; for 
the elementary experiments of a student. J rave the descrip- 
tjwi because it may be useftil to Btudents who nave acces to a 
regular laboratoiy. 



m 

m 

. i 

i 
J J 


*? 



Wherever it is possible bo to do, it is advisable to make an 
opening in the floor where a wind fnmace is to Be built, and so 
to contriTe the buildinK that the ash-pit of the furnace shall be 
in the cellar whence w draught is to come. The inner body 
of the furnace may be either round or square. In crucible oper- 
atioUB, fuel is burnt to waste in a four-cornered furnace ; but on 
the other hand, this form is preferable to the cylindrical for dis- 
tillation and roasting. In the figures, therefore, the four-sided 
furnace ia depicted. The cross section of the interior of this 
furnace is a square of which each side measures 18 inches. At 
e is the grate, consisting of Beveral bam of cast iron bound ti^e- 
ther and turning upon a hinge. The opposite ude of the grate, to 
that which is connected with the hinge, rests upon a bar p. This 
bnr is moveable ^nd can be withdrawn by pulling the knob out- 
ride the furnace. In that case the grate rails down, hangs per- 
pendicularly by the hinge, and lets the cools foil into the ash-pit. 
Below the grat«, a caniJ, d, of the same width as the upper part 
of the fiumce, descends about two feet and terminates in the 



33 APPLICATION or HEAT. 

•ellor. Abore^ the ftimaee ia closed hj an iron plata, h, tiaed 
with Areday, and fastened to an. iron chaui, by the help of 
wliicb, and a pnlley, r, it can be pulled open when it is necessaiy 

to tlurow in fuel, or to stir the fire. There ia a maall hole, n, in 
this plate, which can he covered with a moreahle iron plate. The 
tuHi of it is toaffbrd anopportunity of occasionally oteerving the 
fire. From the body of the furnace, the hot gases paea into the 
chimney, c, by the canal 6; the croas section rf tha chimney, 
like that of the furnace, is a aqoate. The proportions oheervcd 
in the abore diagram are taken from a funiace which was em- 
ployed in the preparation of potassium by the ignition of car- 
Donate oFpotaaii with charcoal, and which gave ovet the pot«»- 
dum in 20 or 30 minutes. The chimney of this furnace was 
npwvds of 60 feet high. This description is gives in MiUeher- 
ficA'« LArbuiA der Chemie. 

The opening, b, between the furnace and the chimney, is 
oommonfy made rather wide, and can be diminished more or 
leas, according to the operation, or the dlSbrence in the fuel 
eoiployed, by the insertion of pieces of fire brick. 

The chimney is provided with a damper for the regulation of 
the draught. 

When the furnace is to be employed to effect a fusion, the 
opening i is closed with a brick. Another kick is placed upon 
the gnt^, and the crucible upon the brick- 
When a -Bubstance is to be heated widi access of atmospheric 
air, as in eupettation, you employ a piece of apparatus termed a 
muffle, which has the shape faured 
in the margin, and is made of fire- 
clay. This ia placed npon the bars 
in such a position that ita mouth 
opens into the cavity ». The suh- 
Btancea which are to be heated in 
the presence of air are placed in 
small cmisaleB npoa the Hoot b m the muffle. The muffle is' 
kept rea hot, and the tur, entering at the opening >, passes Into 
the muffle at b, and escapee by the openings a a a into the chim- 
ney. The aetim of the tur ujion the heated substances is pro- 
moted by agitating them. 

When the furnace is to be used in distillation at high tempeN 
atures, as in the preparatbn of zinc or potaerium, the retort or 
battle is placed upon the bars, o o, and the opening i is dosed 
by a brick, in which there is a hole for the neck of the retort. 

In all cases it is preferable that the adi pit of this furnace 
should be in the cellar, because the heat of the falling' cindei's is 
then not difiiifled in the room where the operator la at work. 
Besides, it is often necesgaiy to diminish or to extinguish the fire 
suddenly. This is done by simply trithdravring the bar p. Such 
an arrai^fement is pecnbarly desirable with a Aomaoe, which, 
like ttus, is employed in the preparation of large quantities. It 
adds to the safety and certaiaty <^ tho>operati<»s. 



APPMCATION OF BBAT. 33 

" 'B^An •FoHNACE. — The hishest iegne of heat ia produced in « 
fanifSSidto the middle of i^ikh air ii forcibly blown from many 
diilS^en't'pHpts at once, fiacb a furnace is oest formed of two 
iron cj^JflteTv, placed one within the other, as shown in the fol- 
lowing: cut, wher^ e e e repreaent the outer cylinder, and the 
inner is shown Imed with, g, a thick mass of fireclay. Both 
cvlindetB are provided with a bottom, and are fixed together at 
tne t«p, air-tight, and in auch a manner as to leave an equal 
«>ace between their bottoms and sides. This is exhibited in the 
i^ure. The smaller cylinder and ita lining of fireclay, is pierced 



near the middle of the sides with eight holes, all pointing 
towards the centre of the furnace. The crucible to be beate^ 
is placed upon stones in the middle of the furnace. The air is 
blown in at the opening a, which is connected with the bellows ; 
H is thus compreeeed in the space b, and thence driven through 
tlie holes jnto the middle of the furnace. The heat ihns 
produced is very intense. In a furnace, proportioned as above, 
and measuring 27 inches from c to c, haff a pound of feldspar 
OWi be completely melted in half an hour. Iron and other sub- 
Stances of difficult fusion melt in it with ease. The fuel used 
for this furnace requires to be very uniform in size, to be all, for 
example, of the biUk of a cubic inch. This uniformitv is gained 
by breaking the fuel to nearly the size required, and then sifting 
it through two sieves, one of which retams all the pieces that 
are too large, and the other lets through all that are too small. 
If coke is naed, it must be of a aort that gives very little ashes. 
Tlie crucibles that answer best are the Hessian ; but neither these, 
nor those of plumbago withstand entirely the melting power of 
this fbmace. 

All furnaces must he placed under a snitable Tent, so that 
snoke and fumes may be carried away by the draught, and no 
mischief he produced by ejected sparics or hot cindera. 



84 SUPFOKTB VOK APPA&ATtrS. 

!□ djfFerent locftlidee, diffwent modes of prodDoing; and apply- 
ing heat are preferred &oin aocideiital differencea in cost and con- 
venieoce. In most parts of Oeroumy, for exan^le, both spirit of 
wine and charcoal are obe«p, «nd eool ^ is net in lue. In 
Scotland, on the contrary, gaa is chesp, tipait dear, and charcoal 
often impossible to be procured- Henoe in different localities, 
ehenuBts are compelled to ehooee different desoriptioos of fuel in 
virtae of the necessities of their positioii. £ven in the «ame 
town, in Scotland, differences anse acddentally. A student is 
Glasgow, for example, hsA, in a chemical iBboraton-, compete 
command of gas and of coke fdmaces. Bat in his lodgings, if he 
wish t« pursue there the study of qu^itative analvsis, he is com- 
pelled in most cases to use spirit done. For taese reasons, I 
hare made it a role, in choosing examples by wbieh to illustrate 
practically rariona &cts and chemical principlee, to t^e such as 
tqtpeared to me to present iq>on the whole fewest difficulties to 
students, not proviood with re^rular laboratoiT aomounodations. 
I have accordingly gtoerally recommended tne xtae of the niirit 
lamp, as being rea£ly procured and readily nonaged — ana for 
very high temperatmres I have recommended tbe argand spirit 
lamp, where it is applicable, and in other cases, Ae blowpipe. 
The use of the latter mstrument I shall exphon in a separate 
section, to which I earnestly request the reader's attention. 



SUPPORTS FOR APPARATUS. 

WuEN voa be^ to think of holding a vessel above, or in, the 
flame <^ a spirit lamp, you begin also to think of the means of 
doing so without burning your fingers. It is by tbe use <£ dif- 
ferent sorts of supports or holders that this object b gained. We 
modifv these supports according to the nze and form of the ves- 
sd to be supported, according to the degree of steadiness required, 
and to the temperature to which the vessel ia to be exposed. 

SUPPORTS FOR SMALL GLASS VESSEI£. 

If the instrument to be supported over a lamp is a glass tube, 
or a. small flask, and the time during which it needs to be held 
is very short, the readiest way, as 1 have said at page 9, is to 
hold the open end of the vessel with the thumb and middle 
finger of the right hand, closing its month with tiho fore-finger 
»f tbe same hand. 

But if the operation b to last some time, or if the gases that 
may be produced are to be allowed to escape, and in their pas- 




avnoKta ran apfabatus. S5 

M^ forth, to warm the 
month of the tabe, then it 
beoomeB neceseary to pro- 
tect the fingers from tba 
ht«t by the interposition 
of ii slip of woollen cloth, 
or of blotting paper, folded 
iereral times fiat, and of 
which the ends are twisted 
together, ag shown in the 
cat, into a sort of handle 
1 br which the tube can tw 
^heid. 

Or j^on may twiat a wire nmnd the tube, and hold the end of 
the wire ia yonr hand. It is prudent to adopt this plan when 
an expksKoi ctp^le of anattering the glaaa 
ia to be ^prehmded. 

Or, finally, joa may take a long flat piece 
if cork, and adapting one end of it to the 
Amonth of the tabe, yon may hold the other 
^endby yonrfingeraad thtimb. Thismethod 
aniwera very well in caaee of subUmatioa 
in anall tnbea, where it is sometimes desir- 
able to have the whole of the inside of the 
tubs visible at once. 
If the object in view ia to ei^oee a watch glass, or a small cap- 
sule, for a short time to the heat product by the flune of 
a spirit lamp, yoa may em- 
ploy the instnunent figured 
m the margin. It consistB 
of a pieco of iron wire 6 
inches long, and as thick as 
the straight wire c, bent into 
the fbnn of a cirele o, and 
having both ends inserted 

hill MiMi^^jM^M^Mm "* "'*" *' ^ '^^ "^ ^^^ of 1 or 

Ij inch in diameter. 
A modification of this simple apparatus, and which answers 
Tery well for supporting amaU cups and crucibles in the flame of 
a spirit lamp, consists 
j=«. of an iron wire, bent 
=S='=a=P==CJ) into a ring at each 
' ^*^ end ; one of them 
about two-thirdsof an 
inch, and the other 1^ inch in diameter; with a straight portimi 
seven inches long between them. Upon this straight portion 
yon place, previous lo the bending of one of the rings, two long 
bottle corks, which form, when poshed together, a h^dle to pro- 
tect the hand from the hot metaL 





I , Google 



■DPP0KT8 row Afr^Rtm. 



Ketorta and flasks can be supported on the 
table, iu &n upright pooitioii, hy meaiu of 
ringsof straw, or Dy rings of tin plate, either 
mapif japanned, or twisted loond with 
straw, string, or wonted. 
A supporter for retorts, flasks, and basins over a lamp mar be 
constructed of stoat iron wire as follows: You take three pieoca 

iof iron wire, one-eighth of an inch thick, andaboiit 
fi>nrt«en inches long, and bend each piece into the 
form of the adjoining upper figure. You th^ 
bind tiiem to^euer, by two and two, at the angka, 
with this w]ie; by this means von produce a 
irame, the upper surfiu» of which is a trian^e, 
like the lower adjoining figure. The riass reoel 
to be heated is placed upon this trian^e, and tlw 
spirit lamp is p1ac«d below it, between the 1ms 
ofthestaiM. This kind of support can he read^ 
" prepared and is both economical and portable. 
For this and other supporta, that are construct^ in sttcb a 
manner that the resting-place of the vessel to be heated is at a 
fixed height above the table, it is neceeeaiy to be provided with 
the means of raising or depressing the lamp, which is to be 
placed below the vessel to afford the required heat. The simplrat 
contiivance of this sort, consists of a series of blocks of wood, 
four inches square, and varying in thickness as follows: — 1, 2, 
1, 4 ii i inch. The price of such a set of six blocks is Is. 6d. 





»-i h, Google 



SUPPORTB FOR &PPABATUS. 



BETORT HOLDER, OB TRIANGLE SUPPORT. 

When you wuh to snppoH a flaak or a tetort for a consder- 
bWb time over a lamp, vou must, to caaes where the cyhnder 
(page 2i) is not available, employ h piece of apparatus generally 
termed a retort ttand. This is represented on the precedinK 
page. It conaiatg of a brass or iron rod, a, one-third of an incE 
thick, and eighteen inches lonr, screwed into the end of a piece 
of boaid, ti, five inches wide, and nine inches Ions; or dse screwed 
into a female screw, e, sunk into the board. The rod must lie 
furnished with a horicontal arm, hsring a ring or a triangle at 
one end, d, and a coil or worm at the other. This arm mnst 
be made of iron or brass wire about one-eighth of an inch 
.titick. The triangle should measure three inchu each side. You 
fiom the worm by fixing the large rod and the end of the wire 
in a rice, and then coiling the wire four or five times round the 
large rod. Such an arm mores loosely up and down the rod, 
but becomes fixed when a weight is placed on the triangle. This 
triangle can be made to support any sort of apparatus, howeTer 
Bmall. Yon have only to lay upon it various sized triangles or 
t(«llis work (p. 26.) of fine iron wire. 

The fbllowmg figures represent two ways of bending wire into 

Fig. 1. Fig. 2. triangles finr this purpose. 

The second method is the 

beat. Some of these trian- 

sles should be made of 

iron wire, not more than 

the thLdeth of an inch to 

thickness. They serve to 

support crucibles to the 

■ flame without carrying off 

much of the heat. 

It is convenient to have, to addition to the laiye retort stand 

described above, one or two others of the same kmd, but of the 

fiillowing dimensions : — 

Upright rod, 9 inches long, ^ inch diameter. 
Foot {of beech), 7 toches long, 2j inches wide. 
Triangle, 2 indies each side, wire Aj inch thick. 
This is the sort often referred to to this work as the triauglo 
Eupport for small vessels. 

When great weights have to be supported, it is perhaps safer 
to provide the triaagles with screw-nuts, to fasten tiiem more 
securely gainst the upright rod, than can be done by the simple 

Eressore of the coil. Bat m most cases, it is best to support 
eavy vessels by means of Sefstroem's holder represented at p. 39. 
Triangles are piefeiable to rings for the support of retorts, 
flasks, and capsules, to consequence of their not so completely 
catting qjf the heat from the "uper part of the vessels they su^i 




38 BirpPORTS FOR APPHRATUa. 

port. A thick ring ia a perfect bBirier to the upward progress . 
of the flame of a lamp. 

GAY LUSSACfS RETORT HOLDER. 
The fbUowing descriptiait applies to a retort-holder eonlrived 
by Gav Ldegac. Ita object u to Bopport the retort, by grasping 
its neckj instead of BUBtainin^ its body, and so to acquire the 
power of placing and of retaining the veMel in any desirable 
position without interfering with the action of the flame upon 




the contents of the retort, a 6 is a board, and e d a round stick 
ecrewedintooue endofit. ThisserreetompportaBortofwoodeR 
finger and thumb, e/, represented in the second figure, as seen 
from above. A is ibe hole through which the stick cdie passed, 
and g the screw by which the parallelopepidon i m is fixabk at 
an^ required 




nut in. It follows from this urangmeat, that the ibrk or 
finger and thumb e/caa be turned on its axis, and be fixed by 
the strew m in any given position. In the npper figure the 
entire apparatus is seen in profile. At o, one-tturd of its length 
&om the end, a hole is bored throagh both limbs, that in the 
npper limb being made smooth, while the one in the lower limb 
is provided with a female screw, and made rather smaller in 
diameter. Hence when the wooden screw o is inserted through 
both holes, it moves freely in the upper hole, but fixes In the 
lower. When it is screwed up, therefore, its head forces the 
two limbs of the fork together, and secures any object that b 



BDFFOKTS FOR 

placed betteten them. The end of the appantua e p ia armed 
' with two groored corks let into the wood, ana serving to equalize 
the preemire exerted by the screw o npon the necks of retorts, 
and thus prevent thcar fisctnre. It is clear that, by raising or 
depreemng the fork /, oi by tnimng it either on its axia A; ^ or 
round about the rod c (^ we con command eveiy deaiiable posi- 
tion and inclination. 

If this instmm«it is intended to hold large retorts, or for use 
on a lecture table, the length ofef should not be lees than 12 
or IS inches. If it ia to be used with small apparatus, it need 
be only 8 inches. Hie opright rod for the one should be f inch 
thick 8od 18 inches long, fbr the other, ^ inch thick and 9 inohea 
long. Nest holders of this deacriptton are gireu in Edb's CAe- 
mieel LtAoralorie*. 

BEFSTROEIfS RETORT HOLDER, 
Another instrument of this kind has been contrived b^ the 
Swedish chemist Skfstbobii, which differs &om the preceding in 




the constroction of the arm only, and not in the npright rod or 
foot. The paiallelopepidon i m of the former figure remains 
also the same in this inetrument, in 
the figure of which it ia marked i n, 
— . BsdoeBlikewisej, the screw for fixing 
-J it on the rod c it But instead of the 
short peg k / in the fiirmer figure, 
there ia in SBreiaoBii'a holder, a long 
round peg Ik l, which can be pushed 
backwards and forwards in the hole, 
k J, or be fixed at any part of it bv 
thescrewm. The block etisaparal- 
lelopepidon of wood, through the two 
ends of which pass two strong steel 
wires, c » d and gt d, laatened above 



n 



40 SVPPOKTS POK APPARATITV. 

in a block of wood by meanBof thennts c c, uid bedt below, so 
that the one holds a small ring, and the other is bent into a hook 
to catch the ring. The block e t moTee freely apon these wires. 
At a 6 a piece of coi^ is cemented, and another atrt. These are 
grooved on the sides opposed to each other, so as to form a re- 
ceptacle for the neck of a retort. The pressure which fixes the 
retort in its position is commonicated by the screw o. This ap- 
paiatuB answers very well lor the support of large and heavy 
vessels. It is prepared for sale in Gla^ow, at the price of 6s. 
The instrnment nven for this snm, is handsomely and substan- 
tially made, and 1 can i«cotnmend it as a nsefnl piece of appa- 
ratus for such operationB as distillation, where it is sometimes 
necessary to cmmect tether several vessels into a mass, the 
weight of which requires a pretty solid sapport. 

A ^mple and powerftil arm, qualified to hold heayr vesseH 

may be made on the prindple of the common vice. It should 

be 6 inches long, formed as 

shown in the figure, and of 

plane-tree wood. The ori- 

) nee a is intended to grasp 

/ the neck of a retort. It is 

rned or closed, and sccur- 
when necessary, by the 
screw. The hole in which the screw works in the upper limb 
is Ixaei adant, so as to permit the screw to remam upright 
whoi the jaws of the vwe are open. The nut of the screw 
presses npon a cross peap, which is fixed across the upper part of 
the hole in the upper limb. A little circle in the figure shows 
its position. The opening of the vice is provided for by the 
hinge b. The butt-end of the instrument is bored, c, for the 
insertion of the support, either perpendicularly or transversely, 
according as you destine the vice to hold long objects horizon- 
tally or perpendicularly. The fixing of the vice upon the upright 
support is effected eitner by the interposition of a bored COTk, 
or Dy a scre^, as are the branches of the retort holders of Out 
LussAo and Sefstrobh. 

It is scarcely necessary t« add, that this vice is adapted to 
hold thin or small objects, when placed between its lips at the 
extreme end. It is used by Bbbzbuus to support a water bottle 
in the washing of precipitates. 

METALLIC TUBE HOLDER. 

A DraADVANTAQ! attending the use of these wooden retort hold- 
ers, particularly when Toade of a small size, is, that the wooden 
screws, being of small mass, soon lote their thrauU, and wHl then 
no longer hold a vessel with safety. To remedy this evil, I have 
contrived a metalUc holder in wnich there are no screws, but 
which has, nevertheless, every dearable movement, and which 




41 

ie at once efieotire, dmable, and c)i«ap. It is a modification 
of an apparatus employed by Professor Orabam. Tlie iustra- 
ment is sold in Olaasow for eight- 
pence, or mounted with a foot and 

rod, &)r one sMUing. 

a b represents a piece of strong 
tin plate, aboat lOi mchea long and 
iiflif an inch wide,T)ent flat in the 
middle at a, and a little rounded at 
each end b. c is a double coil of tin 
plat«, half an inch wide, adjusted 
to run eadly, . 
J but not loosely, 
' ' up and down a 
ft. The object 
in making a 

double cou, te to give auffident 
substance for the fingera to catch 
hold of nadily. 

When the coil c is moved towards 
the end a, the finger and thomb ft 
open by the spring of the metal. 
If, then, any object is placed in tlie 
hollow b, snch as a glass tube, a 
blowpipe, or the neck of a small 
flask or retort, and the coil e is 
brought back towards the end 6, 
the pressure it exerts there, fixes 
the object with sufficient fiimnesa 
to be held steadily over a lamp. 
Thus the coil c acta the part of the 
screw oin the apparatus previously 
described. When the vessel to be 
supported is large or heavy, or of a 
corneal shape, the grasping power 
of the claw 6 is much improved by 
the insertion of a bit of woollen 
cloth or of thin sheet Indian rubber 
between the clasp and the vesseL 

The instrument in this state can 
be used instead of the contrivances 
described at page 36, to support 
tubes or amall fiaeksover the flame 
of a lamp. 



There remains to be described the sahetHate in this apparatus 
for the parallelopepidon i m in the former instroment (page 38) 
which serves the purpose of holding the fork on the upright 



43 SUPPORTS FOK APPAKATITS. 

rod, and of taming it on 
its axis. In the annexed 
figure, a and b are two 
small cylinders of tin 

Slate, represented in 
leir full siie. They 
are each an inch long. 
c The larger is two~thiras 
of an inch wide, snd the 
latt«T half an inch wide, 
or it is exactly so lai^ 
aa to enable the end a of 
the former instrmnent 
to turn round in it. The 
smaller cylinder is sol' 
dered perpendicular to 
the larger, and the larger 
is filled with a cork, having a hole in the centre by which it 
slides up and down, or turns round about, on the upright rod 
d d. The smaller i^linder is also filled with a cork, or rather 
with two corks, which hare between them a qiace just large 
enough to admit the end a of the fork a b, which must be pushed 
into the smaller cylinder tilt it comes into contact with the 
cylindero. This divided cork is shown at c. It must he cemented 
with wax to the thin slip a, but must, with the tin slip, turn 
freek in the cylinder i. 

This apparatua is represented in a connected state in the fol- 
lowing figure, where d d ia the upright rod, a the tin cylinder 
that gives the up-and-down 
and round-about motions, b 
the cylinder which enables 
the arm of the ftnger and 
thumb to turn on its axis, c 
the clasp or finger and thnmh, 
and e a flask held by it in 
a vertical position. 

The power which in this 
' apparatus replaces the three 
— screwsof QiY Lusssc'a holder, 
is the Jrietion of the corks in the tin cylinders, on which I find 
that greater reliance can be placed than upon the wooden 
screws, while it is a power much more under the control of the 
operator. Two hands are required to mani^ the screw, when 
the apparatus is loaded, while cme is suf&cient to twist round 
the cork. 

The rod and foot ad^tcd to support this tube holder are those 
of the small retort stand depicted at page 86; or, what answers 
better, a foot of the same kind with a rod of wood instead of 
the brass rod. The acid vapours produced in the course of ex- 
perimenting, soon corrode the brass rod so much as to prevent 




ntPPORTS FOB APPAKATUS. 49 

the cotk of the tnbe holder from mimmg up tmd dovn with 
Boffident &cility. This is not the case with a wooden rod, whidi 
akonld he about 9 inches long, and two-fifths of an inch in dia- 
meter. The cork moves easiest when the rod is leased with 
tallow. The cork which ia fixed upon e, and wokb within i, 
should also be greased. 

I subjoin a fignre of the tube holder in a complete state, 
grasping a glass tube. This apparatus is able to support any 
glass T^sel, the neck of which does not exceed en incn in dia- 
meter, and the bod; of which is not larger than is sufficient to 
oimtain 3 or 4 ounces of liquid. In cases where the apright 
tod is too short for the purpose in view, the entire apparatus can 
be raised above the table by means of the blocks deacribed at 
page 36. 




The following cut shows the method of supporting a blow- 
pipe by this holder. 




SDFPOKTS rOE APPAKATUS. 




To hold up at varying heights from the table, lamps, receivers, 
and other apparatus, it is convenient to possess a loot », with 
wooden sapports mich as are Tepre«eiit«d by ^ b c, all provided 
with Htalks ad^ted to the hollow tube of the foot b. TTiese 
are then fixable at any given height by the screw e. — The flat 
plate A is intended to hold a lamp, but it can also be used to 
BUpport a round bottomed vessel, if provided with a straw ring. 
It IS better, however, to support round bottomed vessels, re- 
ceivers, basins, &c,, between the three pegs of c, which hold 
them more securely. — The crook b is intended to support tubes. 

It often h^peus in the adjustment of complicated sets of 
apparatus, as for example, of that requisite in the preparation 
of solutions of gases, that some one particular piece of the ap- 
paratus requires to be made to incline a little on one side, m 
order to bung it info a good position in respect to the a^acent 
pieces. This can generally be effected by tilting one dde of 
the vessel that is to be inclined, or one side of the foot of the 
retort holder on which the vessel rests. To be able to effect 
this tilting when needful, you should bo provided with two 
pieces of board, each 4 inches sfluaro, and wedge-shaped; one 
of them an inch thick on one side, dimimshins to a quarter of 
an inch on the opposite side, and the second piece, a quarter of 
on inch on the thickest side, leathering off to nothins. 

Various other means of supporting vessels, or of adjusting 
them to one another, yet remam to be noticed; but they are of 
lesi general utility than the foregoing, or they relate to opera- 
tions which fell to be described in subsequent sections, and 
which cannot be introduced here without anticipation. 

Of all the supports here mentioned, the most useful to a 
student are the small trionrie and rod (page 37) which costs 
lOd., and the tube-holder (page 41) which costs Is. These, 
with the lamp furnace (p^ 24), are sufficient for many opera< 
tions. The neitt most usefil supports are the set of blocks ai 
Is. 6d. (pt^ 36) and the large S^/itroemt holder at Ss, 



TESTING. 

A T««t, or a St-agent, la a sabstance which has ihe propert; 
of producing a particnlar phenomenon when brought into con> 
tact with some other substance, whereby the presence of that 
other substance is made manifest. The phenomenon produced 
by the bringing of an unknown substance into contact with a 
substance of known properties, b caUed re-actum, and the known 
substance that produces the phenomenon, a recent. Thus in- 
fiimon of galls re-acta npon solutions that contain iron, and 
produces a black colour. Infusion of galls, therefore, is a r«- 
agent that serres to indicate tlie presence of iron, or, briefly, it 
is a Tat for iron — a witness that testifies to the presence of 
iron. A drop of any acid let fall into a blue solution of litmus 
changes its colour to red. Litmus, therefore, is a test Ibr acids. 

Generally speaking, tests are applied to use in the state of 
liqliids. Any unknown substance that is to be examined is 
brought into solution by a suitable liquid, and the substances 
that are to re-act upon it, in order to produce phenomena such 
as shall lead to its recognition, are also brought into solution. 
The subsequent and ^stematic mixture of these solutions, and 
tlie examination of the results, constitute what is called Liquid 
Ufling. In some cases, however, both solid and gaseous snb- 
Honoes are employed as tests. 

The two phenomena of most universal production in liquid 
testing, are lAange of colour ani/brmatUmi^tolid matter. Both 
of these phenomena are owing to the production in the mixed 
solutions of new compounds possessed of new properties. The 
reason why in some cases there is a production of sohd matter, 
and in other cases no snch production, ia, that sometimes the 
oompounda which are produced are tohihie in the resulting liquid, 
and sometimes are intoliMe. Hence this production of solid 
matter, or as it is called preeij^tation, depends not merely upon 
the nature of the substance that is produced, but npon uie sol- 
vent powers of the liquid in which it originates. Accordingly 
the same compound, produced in one liquid, dissolves, and in 
another, precipitates. It requires a general acquaintance with 
tha solvent powers of dilFerent liquids, and with the properties 
of a wide range of chemical substances to enable one to interpret 
aridit the indications afforded by the operation of testing. 

This information is to be sought for among the characters of 
chemical bodies, and among the Instructions for Chemical Ana- 
lysis, presented in another part of this work. I have here only 
to treat of the proper application qftht ttttt, and to describe the 
^iparatoB, and explain the terms, which relate to this operation. 
I uiall commence oy explaining what is meant by neatralitatitm, 
and by showing the Telations of acids and alcaliea to colonrod 
test papers. 



46 

NKUTRiLisATioN. — Actton of Actdg on Vegetable Cohurt. 
fMake these esperimcnts in. a glass, such as is shown in the 
margiD, using a, stirrer of the 
annexed size with each glBss.^ 
/\ ' Mix a little tincture of cab- 

bage with a glass of wat«r, a6 
as to form a Seat blue liquor. 
Drop into the mixture a little 
sulphuric acid. The colour will 
then turn red. Every other 
acid produces the same change. 
Make a blue mixture of wa- 
ter and tincture of litmus, and 
add a few drops of any acid to 
it. The colour will turn red. 

Put a drop of any acid into a 
glass of water, and dip into the 
mixture a slip of blue litmus 
paper. The colour of the paper 
will be chan^ to red. 
Action qfAicaUtt on Vegetable Cohan. — Into a mix- 
ture of water and tincture of cabbage pour a few drops 
of Uquid ammonia, or of a solution of potash. The blue 
colour of the li([uor will change to green. All aicalies 
produce this chiin^. 

Make a yellow Gquor by mixing tincture of turmeric 
with water. Add a little lig^uid ammonia or solu^n 
of potash to this liquor. The colour will become brown. 
If you mix water with any alcali, and then dip into 
it a slip of turmeric paper, its yellow colour will he 
changed to brown. 
Counter Actwtia. — If you add an alcaline liquor to the tinc- 
ture of cabbage which has been reddened by an acid, the hquor 
first regaina its blue colour, and finally becomes green. If you 
add an acid to the tincture of cabbage, which has been rendered 
green by an alcali, the liquor becomes first blue and finally red. 
The reddened litmus paper reguna its blue colour in an alca- 
Une solution, and the browned turmeric paper regains its yeUow 
colour in an acid solution. 

Try the effect produced on litmus paper and turmeric paper 
by diluted nitric acid, and dilute solution of caustic potash, 
luen mix the two diluted liquids together, adding the one \a 
the other gradually, and trying from time to time the action of 
the mixture on the coloured test papers. You will find a point 
at which the mixture affects the colour neither of the litmus 
nor of the turmeric. 

When a liquid effects no change in the colonr of turmeric 
and litmus, it is said to be neutral. When it tnms blue paper 
red, it is said to be atAd. When it turns yellow paper brown, 
it is said to be alcaline. When you render an acid Uquid alca- 



line by adding an exeett of an alcaline solution to it, yon are 
said to gvpertaturate the liquid. If you then render die auper- 
SBturated solution neutral, by adding a certain quantity of acid, 
you perform what is called neulralUatUm. 

In trying the neutrality of a liquid, you may either dip the 
end of the test paper into the liquid, or draw a line acron the 
slip of t«Bt paper with the point of a clean glass rod dipped 
into the liquid for trial. The latter method is the cleaner of 
the two. 

The preparation of these coloured liqnida and of the tat 
paperg will be fliUy described in the article on vegetaMe oohurt, 
section Hydhookn, where also will be given an acconnt of the 
peculiarities of their action with different chemical substances. 
Each test paper is bound up into a book of the follon-ing size, S 
leaf from wluch is used for every different experiment. Thick 
cotton thread dyed with the coloaTed tests can also be conye- 
nient)y used in testing. 




TasTiNo. — Generally speaking, a liquid to be teeted cont^ns 
either an acid, an olcali, or a s^t of some metal. It should be 
put into Bnitable glasses, and the tests added with suitable pre- 
cautions. Each test, upon being added to the solution of the 
Bait which is to be analysed, either efiects no change, or changes 
its colour, or produces a precipitate, and the precipitate is either 
white or coloured. The coiutituents of salts are acted upon 
differently by different testa, and are consequently arranged in 
Tables for Testing, in dijferent sections, under the names of the 
different t«sls. It is irom a comparison of the effects produced 
by a variety of tests applied to a given saline solution, that an 
opinion is formed as to tue nature of the salt which the solution 
contains. 

There are commonly two sets of tests used in testing. The 
object of the one set is to detect the bate or metallic part of the 
salt; that of the other set to detect its acid. 

It is necessary to use a very sm^ quantity of the liqnid to 
be tested; if it is scarce, three or four drops will be sufficient; 
if it is plentifo], as much as Ms half an inch of the g]Bm may 
he t^en. When the solution is concentrated, a smaller quan- 
tity answers than will fiiifil the object when the solution is 
dimte. The tests must be added in very small quantities. When 
a test is delicate in its indication^ you may dip the end of a 
dean glaas rod into the liquid test, and then stur the liquid in 



48 TISTtNO. 

the t€«t glsM with the wetted end of the rod. When tt rod b 
dipped into oil of vitriol, and then into a clear aolutioa oontain- 
ing a salt of barium, ron immediately obserre the fwmatkm of 
a white precipitate of sulphate of barytee. If the test to be 
applied is not delicate in its indicationB, a more conaiderable 
quantity must be ^plied. Occamonally, it ia necessary to add 
a conaiderable quantity of the teet, in o^ler to re-diasolTe the 
enbetauce precipitated by a Bmall quantity. It is always im- 
proper to add a teat liquid in large quantity at first; the proper 
method is to drop it in gradually. 

Slirr^t are neceeeary to be proTtded. Their use is to mix 
the test with the solution by agitation or stirring. They shonld 
be made of strong gk<a tabe, or of round rods, proportioned in 
lenaih to the elasses they are to be used with, and &om one- 
e^hth to one-uiid of an inch in diameter, according to their 
length, and to the probable stifineas of the mass of prec^iitate 
they may have to stir. Very useful sizes are 3 inches Itmg and 
i inch thick, 6 inches long and J inch thick, 9 inches long and 
I inch thick. The ends of the tubes must be closed neatly be- 
fore the blowp^. One end should be somewhat pointed, the 
other round and blnnt. The shape is shown at page 46. They 
must always be made of soft aim, otherwise they scratch and 
spoil the test glaseee with whida they are used. 

Narrow slips of wmdow glass cannot be substituted fbi glass 
rods as ftirrers, for their numerous loughnesseB and sharp ^ges 
make it tJike difGcult and dangerous to clean them. 1 cannot 
conceive whyDrRsin advises etoAente (BudimenU qfChemitCry, 
p. 89) to use such troublesome and inefficient rubbish, instead 
of round stirrers. A r^ard to economy can be no reason, be- 
cause the price of the heat smooth gloss rod ii seldom much 
inore than a penny per foot. 

With one of these stirrers the solution under process of test- 
ing is agitated, after each addition of a drop or two of the test. 
If no precipitate appeais ailer several additions of the test, the 
solution is allowed to repose. Precipitates do not appear in some 
cases, ewecially where the solution is very dilute, and where 
the precipitate assumes a cryatalline form, until some time haa 
elapsed. Consequently the effect of the test cannot be judged 
of m an instant. Modifications in the production and propeitiea 
of precipitates are often produced by heat and light, by the 
oxygen and carbonic acid of atmospheric air, and by evapora- 
tion and crystallisation; all of which actingpowers must in cer- 
tain cases be allowed time for operatiwi. Whenever this occurs, 
it is proper, as a means of nreventing mistake, to affix a bit of 
gum paper to each glass which is set aside, stating the name of 
the solution that it contains, and with what re-agent it is 
mixed. The precautions necessary to be taken, to free the in- 
dications of each particular re-agent from amb^uity, will be de- 
scribed in subsequent sections. 



; Coo;jli: 



49 

IsKi OcAHii. — Very difivrent are the (ortat that hare been 

pecownended as beet suited to contain tbe email portion of a 

•olutica which is to be mil^ected to the action of a le- 

n^ent. Smatl cjliDdera of ^laae, one inch wide and 
three inchei lM>g, mmmted on a short italk and foot^ 
have been much used for this purpose. But this ibnn 
of test glssE is objectionable, as being too capacious at 
the bottom, and therefOTe not adapted to the testing 



of small quantities. Olamea of this shape, but of 8 
or 10 inches in height, and 2^ inches ui width, are 
still adrantagEonsly used by tecturere for performing 
class expeiments on precqiilation, where the dianges 
ere intended to be seen b; a distant or nnmerooB audience. 



^ 



Uehby Rosb, in his Amtlgiieal Cliemiitry, recommends as the 
moBt uaefiil Teasels for testing, straight tubes of white glass, 
such as the one ^ctnred, c, on page 8. He notices also that 
Goniesl wine glasses can be used for testing, but be decides iu 
faTOur of tbs tubes. His reason for the preference is, that in 
such vessels the liquid can, if necessary, be heated ovar the 
fiame of a spirit lamp, which is not the case with glasses that 
stand Dpon a foot, whUe the heating is in many cases of qualt- 
tatire analysis a practice of great wtility. The best length for 
such tubes is six inches, the width two-thirds of 
an inch. A single tube of this kind can be sup- 
ported by a large perforated cork. But as in 
k general a great number of tubes are employed in 
■ testing asolution, it isproper, according to Rose, to 
I be provided with a Hmall fi^me which can hold 
' nineteen of such tubes in two rows, the glasses 
in the upper row being rather smaller ttum those 
in the under row, and the largest being of the size above-men- 
tioned, namely, six inches long, and two thirds of an inch wide 
Such a frame is figured below. 



»-i h, Google 



50 

It is, perhaps, more convenient, where tabes of this Icind are 

nsed, to support them, not in a aingle frame that holds k> largte. 
a number, but in aeTeral saull ironies of 4, 5, or 8 holes each. 
This I recammend particularly^ where studeuta are to be exer- 
cised in Bystematic testing according to methods laid down in 
Tables of'^Tests. Foi example, where Leading or Indicating Tests 
are ammged in sets of 4, 5, or 8, as they are in another part of 
this work, it is advisable to hare the test tnbes also in seta of 4, 
5, and 8 to correspond. Such a ^stem will be found to save 
considerable time where a number of students are to work on 
the same class of subjects. And as the arrangement of the tubes 
in the frame serves to indicate the order in which the testa are 
added, there is a security against mistaking the results of the 
operations. For example, if the first test in the table of tests ia 
carbonate of soda, end if S or 6 tests have been added to as 
many different tubes, the first tube in the frame, and never 
any other, should exhibit the result prodnced by the carbonate 
of soda. It is a good plan to label the frame in front of the 
holes with the names of the tests that aie to be used with the 

A tube frame of the sort here referred to, is represented in 
the following cut, where a and d represent a slip of wood (plane- 
tree answers best) li inch wide, and G or 8 inches long, accord- 
ing to the number o? holes to be made in it Ibr the tubes, b is 



';^- O O O O O O -^^ 

the foot, one-third of an inch thick, one and a. half inch broad, 
and half an inch longer than the upper board a. c are two 
small turned pillars which support the perforated board, one 
and a half incn above the foot. The holes are made a little 
wider than the tubes, and are a qnarter of an inch aipait. Ex- 



cradv for uae. The price of mch a frame ia Bd. 

The next figure repreaentB a tabe &une adapted to fonn part 
of the portable laborotoiy of a travelling mineralogist, ft ia 




formed of tin plate, and japan- 
ned. The platform x x is 
perfonrted for the reception of 
6 tubes of half inch width. The 
holes are one-eighth of an inch 
apart. The jdatform is one 
inch wide and 4^ inches long. 
The holes in the loweT platform 
are a little nnaller than those 
in the npper, m that, though 
the ends of the tuhee enter 
them, the tubes cannot pass through. The apparatus has there- 
fore no need of a base. The supports at the ends are 2 inches 
high, 1 inch wide at the fop, and widen out to 1^ inch at the 
bottinn. The sides and platforms are fastened together by 4 
hina;ea at x x x tc. When not in use, the frame can be shut flat, 
as mown at 2, in ^irtuch form it packs into small space. The 
tabes are carried in a little box. 

There is, however, an inconvenience attending the use of 
tube frames of this description, which is not dwelt upon in 
chemical books, but which proves to be annoying in practice. 
This inconvenience arises from the circumstance Uiat the tubes, 
standing always ready for use, with their open mouths upper- 
most, are commonly, when required for testing, found to be full 
of dust, and to require cleaning. After many attempts to find 
a remedv for this evil, I succeeded by means of a tube frame , 
of the following 



»-i h, Google 




£2 TEETIKO. 

Q Tepresenta* board IM inches loiii;, 3^ Eneiies wide, and ^ incli 
thick, biaa board, 0^ utchM long, I J inch wide, and one-eighth 
_ inch thick, SDnMNrted ot«t the fint board 
by two tiun^ pillars c c, three inchei 
high. The poBition of the Bm&ll board 
ia-Qot over tne centre of the large board, 
but on one side, aa shown by the annexed 
figure, which is an end view of the appar- 
atos. The small board is perforated with 
Sholea fdj, eachseven-tfinthgof an inch 
in diameter, and three-tenths of an inch 
apart. Exactlynnder each of these holes, 
there is in the large board a cavity, six- 
tenths of an inch wide at the top, and 
three-tenths deep. An inch distant from 
each cavity, proceeding towards the op- 
r poste e^ of the laige board, and at huf 
an inch distance from the edge of the 
board there is fixed an upright peg, as shown in botn figures, 
and narked e in that above. In ail there are 8 P<^ ^ach 3 
inches long and three-eighths of an inch in diameter. The whole 
apparatus is constructed of plane-tree wood. 

Eight test tube of the laigest size, namely, 6 inches long and 
i inui wide, ere nsed witii this test stand. When not in uae^ 
nie tabea, previously cleaned, are inTertsd over the pegs, ae 
shown at/in both ^guiefl. When required for testing, they are 
-turned over aaatg^ and supported in the holes d. 

Ag^st the foot of the l^egs, on the inner side, and extending 
the whole length of the row, is nailed a ieathcr-edged slip itf 
food, ^ inch wide, and | inch high at the eide where it touches 
thepegB. The use of this ridge is to keep open the mouth of the 
tubes, BO that when after use they are washed and placed upon 
the pegs, the water may drain out and the tubes become diy. 
The pomtion of this ridge, and the manner in which it elevates 
the tubes a little above the foot board, and tilts them a little on 
one side, is represented in the figure above, where a cross sec- 
tion of the feather-edged slip of wood appears on the lett side of 
the peg. This ridge is omitted in the front view of the appar- 
atus, where every peg is represented as iiimished with 
a separate support &r eadn tube, whereas it should 
have shown a single slip running along the front of 
the entire range of pegs. 

This apparatus fiuly answers its intended purpose, 
and greaUy facilitates the use of tubes as teat glaaaes. 
The price at which it is sold in Qla^w is Is. 6d., or 
fitted with tubes, from 3s, to 4s. 
. AnotherGerman chemist, Wackbnbodbb, recommends 
» teat glasses of a very long conical shape, like the figure 
in the margin, or like champaign or ale glasses. Of 
thia form of vessel he describes two mzea as moat uae&l: the 



TBBTIKO. 53 

smaller 1 inch wide at the mouth, 2A inches deep within, and 
4 inches long including the foot; the lai^er 1| indi wide at the 
mouth, 3^ inches deep within, and S^ inches long, inclusive of 
the foot. He admits the necessity of wanning the solutions 
in some cases of testing, but states that it is better to transfer a 
solution that requires heathig, into a small flask, than to use 
tubes in all cases of testing. 

Glasses of the long narrow form last described, may be i4iplica- 
ble in two cases of testing; — 1. When the solutions are small 
in quantity, bnt concentrated. 2. When the precipitant is to 
be added in large quantity to re-dissolve a precipitate. The 
acute angle of the base makes them useful in the flret case. The 
large capacity of the principal glass makes it handy in the 
second case. But there is iu general testing, a case of frequent 
occurrence which these glasses do not seem well adapted to 
answer: it is where, in consequence of the extreme dilution of 
the solution, the colour or the precipitate produced by the test 
is too slight to be readily seen except in a prettj^ large ma»» of 
the mixture. Now this mata yon cannot nave in such narrow 
glasses. Unless you fill them, you con have no body of liquor 
to look through; and though you may sometimes discover a 
tint by looking dovm into the liquor, 
such a method of observing is not a 
' good one. This defect is obviated in 
the glass fiaured in the margin, which 
resembles the test glasses used in the 
laborato^of Professor Clark of Aber- 
deen. The Jieu;ht of this glass is 3J 
inches. The width of the mouth is two 
inches, and the perpendicular depth of 
the cone is two inches. The width 
therefore in proportion to the depth is 
greater than that of wine-glasses or any- 
ordinary test^^lasses. It is in fact made 
so, iu order to get that broad inatg of 
liquor to took through, which most 
readily shows the shght changes of 
colour produced by re-agents in very 
dilute solutions. The capacity of this 
glass ia one ounce. The length of the stalk nearly 1^ inch. 
The width of the foot 2 inches. It is provided with a spout f<« 
the convenience of pouring hquids into a small flask, when it Is 
necessary to warm them. 

I have yet toenumeratcsuchof the qualities of a good conical 
test glass as are independent of the considerations noticed above. 
It should be of very clear and colourless glass, worked smooth, 
and not misshapen, streaked, or blebby. The stalk should be 
thin and without ornament, and the wdee of the glass thin 
where the apex of the cone joins the stem. I^ on the contrary, 
the glass is tliick at this point, and the transition clumsy, it 



54 fSSTIKO. 

will be hnpoB^le to test «mail qu&ntitiesnit wilii anyreftBon- 
able chance of Keeiitg the pesults. The pomt of the cone within 
should be biiibII, round and smooth. It must not run dovn 
into a capilloiy point, Otherwise it cannot bo eaaily cleaned, nor 
must it ri»e up into a hump, nor yet be i^iTead out into a Sat 
plain; allof which defeota are more commMi in had glasses them 
unobservant people im^ine. 

' Test glasses of this Idnd are the-moM usefiil, the men ddi- 
catety they are farmed ; but the cmptoymsnt of well made 
glassee in a laboratory meets with a serions obstruction in the 
astonishii^ clunraaefle of some iperBons. I hare Been students 
of chemistry handle test glasses with km care than a cannan 
doeS'B dram elmm. Some of them appeeMd to feel pteunre in 
applying the lever power of their hAa*^ fists to the two ends of 
the glaw, and twisting it in two-at the shank. They did thja 
nnder pretence of wiping thsm. Experimenters uf this ewt 
ought to be detdgnated in every laboratory as the ''awkward 
sqaad.' I was once told by a nofessor, that his- practical stu- 
dents had broken six dozen of test glasse» in a smgle season. 
He told me at the same time that he nerer had hod so httle reason 
to be gratified by the progreee m science of hie class. This 
proves very clearly that test glasses are never brokai in large 
quantities hut by stupid people. It would be proper to difmias 
students of this kind from a laboratory on the same ground 
that iocuiabte patients are -dismissed frota an ho^ital — to moke 
room for others that are not incapable of improvement. 

For the enidanee of euoh as do not intend to join the >'awk- 
ward squad," 1 may asy, that in wiping a test glass with a cloth, 
both hands are to be at mice applied to the cone or to the foot, 
and neter applied one to each end of the giass. While yon 
wipe the interior of the glass, your left 
hfuid rfionld hold the outer part of the 
cone. WhRe you wipe one side of the 
toot, your left hand shoold hold the 
opposite side, &c. 

Another form of the conical teat glas» 
is represented in its full ^e and ^o- 
portions in the adjoining section. The 
re-actions that take place in this glass con 
be readily seen, though not so well as in 
tiie glasa previously described. It is of a 
handy sac, and is veiy easily cleaned by 
the finger or thumb covered with a 
cloth. It K very strong, and not easily 
twisted off the jiank. In the fUtration 
of small quantities, it can support a 
paper filter without a funnel. It packs 
■ m small compass if wanted fiir a port- 
able laboratory; and it can be made to sell at a low price. 
- Each of these test glasses shwld be provided n-ith a roand 

.. Cooglc 




Miner, OB described Bt page 4a, made ofglaMrod, | of a 
thick, and 3 inchea Long. ' 



The best method of mixkig fluids in teat tubes is, generally 
Hi>eakiiig, th&t of clodng the tube with the foTefinger and th^ 
-giving it a shake. A cleaoer bnt lew eflectnol mode of agitatiMi 
conaiats in Bturinv with a glaae rod. 

When extremelv small portions of a liquid an to be tested, it 
-is BometimeB Qsefiii to employ fiat plates of window glass. The 
noicDOwn liquid is applied to the cilan in diopa by means of a 
glass rod, and the test is added to it m the same manner. Watcb 
^laaaeg, however, answer better than flat glass for minute test- 
ing, and they Hnswef better in proportkm as they are smaller 
and more concave. The roaaon is, that slight precipitateB pro- 
4nc«d on a flat sur&ce spread out so as to become invisibk. 
This greatly limits the use of flat glass. The evil can be pai-- 
tially, but only partially, remedied by the employment of plates 
of coloured glags— dark green, blue, or brown, A great, ana, as 1 
conceive, an exaggerated degree of importance has, nevertheless, 
iieen recently ascribed to the use of flat glass in testing, by Dr 
Keid of Edinburgh. In a few exp^iments of demon&tratum^ 
where the teacher has liberty to choose the most striking re-ac- 
tioos, and cam work with solntions in a state of concentration, 
the fiat-^lasa may, indeed, exhibit sufficiently good resnlts. But 
in expenments of researdi, where the operator has Bften to em- 
ploy very dilute solDtiona, and where the changes prodnced by 
the tests are sometimes so very dig^t as to be scarcely visible in 
the beat conical glasses, it is a &rce to qieak of testing on flat 
glass. 

Re-aomtb.— It isneceeaary, for exptoiments of research, where 
particular nicety ia required, to be fomiahed with re-agents in the 
veiy greatest possible degree of purity ; but, for many ordinary 
purposes, the different BobsCBnces-may be madenseorin the de- 
gree of purity at which they are sold by respectable dmsgiatB, 

Solntiona of aalta must be prepared by diasolving the soud snlh 
stances in distilled water. 

Yon ought never to keepBlai^quantitrof a test in solation, 
and never prepare a solution which is liable to spontaneous de- 
Goropositiou, until the moment when yon are going to employ it. 
In general, your saline solutions should be nearly concentrated ; 
that is to say, the water should oontain neariy as much of the 
salt as it is capable of disaolving. If at any time you require a 
dUute solution, for accurate neutTaliaation or other purpose, you 
mix a little of the concentrated solution with distilled water m a 
separate ^laas. The proper strength of teat aolutiona, intended 
fbrtheprodnctiOB of particular phenomena, ia generally stated 
in thia work. 



56 TXSTIMfi. 

Your test solutions mnst alwsys be transparent and free from 
deposit. In preparing them, you put the salt and water into 
a glaaa, and stir them until the water leaves no portion of the 
salt undissolved, or warm the mixture in a small flask placed on 
the hot plate or trellis of the lamp furnace. You then pour the 
solution tlirough a paper filter held in a funnel (see article Fil- 
tration,) and receive it in a bottle which must be previously 
placed below the neck of the funnel. 

Many crystaUised salts can be partially freed from their impu- 
ritiea, hy re-crystallisation. You dissolve the crystals in distilled 
water, niter the solution through paper, and evaporate it in a 
porcelain basin, placed over the lamp furnace, until its sarfaoe 
exhibits a species of film. You then set the solution aside on a 
cushion to crystallise, and when it is cold, you separate the crys- 
tals from tile mother-hquor, whldi,'if small in quantity, and not 
veiy valuable, is thrown away ; but if of considerable bulk, is 
again evaporated, and set aside to produce a second crop of crys- 
tals. These, however, are nearly in all cases, leas pure than the 
ciystals first produced. 



Bottles fob Rb-aoentb. — Liquids of all kinds must be pie- 
aerved in glass bottles provided with glass stoppers ; the use of 
corks is inadmissable. The bottles and stoppers must fit well to 
each other, otherwise something may get into or get out of the 
bottle, and in either case spoil the re-agent. Thus, sulphur' 
■' ittract water from i' ' ' .■ - . 

e ommoniacal gas. 
ties should be of a ., 
The neck should not join the bod' 



acid mav attract water fixna the atmosphere, or hquid ammonia 

~^ exhale ommoniacal gas. 

The bottles should be of a cylindrical form, short and broad. 
_i_ _i. .._iji jjpj j^jjj jj^g body ahmptly, producing angles 
of this sort, J_, hut should be shaped accord- 
uig to the annexed figure, otherwise the liquid 
they cont^ does not pour ontwell. The rim 
round the neck should also be thin, flat aiid 
uniform, otherwise it is impossible to pour or 
drop out the liquid without letting some of it 
■run down on the outside. Bottles containing 
volatile acids generally acquire an external 
coating- of crystaUine ammoniacal salt, which 
makes them unpleasant to handle, particularly 
when this coating is mixed with a deposition 
of dust and soot. It is easy to prevent this by 

firoviding each bottle with a glass cover — a 
ittle beU glass, or a short botde sufGciently 
wide to go over the neck and stopper, and to 
rest on the shoulder of the bottle. Such a 
cover is exhibited in the cut. Bottles are 
sometimes made with covers of this kind adjusted to them by 
finding. These, however, do not answer the purpose, becausd 
uie rim of the t ottle is removed hy the grinding, and the botlli 

.. Cooglc 



TESTINO. 5T 

is no longer adapted fbr pouring from. If is, beudes, unneces- 
sarr that theee covers should fit wr t)^t. 
The aize of test bottles mnM be reflated by particular cii^ 
. cnmstances. A set for a student who works alone, and on amiUI 
-quantities, and a Bet for use in a laboratory, where many persons 
are actively engnged, ought necessarily to be of very different 
magnitnde. AU that it seensneedM to say nnder this head, is, 
that bottles smaller or larger may be taken for each re-agent, 
according to its more or less frequent use. Dittilled water, being 
used in lareer quantities than any other liquid, may be kept in 
large veaaelB. Green wine bottles may salt the purpose of a stu- 
dent. iSpiHf o/wint for feeding tamps may be kept in a siiuilar 
bottle. Oil of vitriol, nitric acid, mnriatie add, liquid ammonia, 
and caustic potash in solution, may be provided with the largest 
size glass-stoppered bottles, which for a student's use may be of 
4 ounces capacity. Bottles for these five liquids may have the 
name painted in enamel ; snch bottles cost Ss. each. Next to 
these, the testa used in greatest quantity ore those which head 
the columns in the tables of indicating tests. These may be put 
into bottles of two or three ounces capacity ; while other tests, 
of lees frequent use, may be contained in soifident quantity in 
ounce bottles. 



TuiNsvisiNo OF Tests. — The method of pouring from a bottle 
a this. Yon turn up the bottle and wet the stopper. You draw 
with the stopper a wet line irom the orifice tJ the bottle to the 

extremity of its rim- Against the --'- ■ " ■^- ' '— - — 

hold the stopper in a perpendicular 



extremity of its rim- Against the point of this wet line von 
hold the stopper in a perpendicular poation over the veseel in 
which the test is required. The bottle is then raised to a hori- 



zontal position, and the test runs along the wet line, and down 
tlio stopper into its destined ixtcipient. 

But it is often necessary to use so small a quantity of the test, 
that it is nearly impossible to transvase it in this manner. You 
may succeed sometimes in applying a single drop by pouring, 
but you cannot always do so, and it ia better to avoid accidents 
which can occur, and whidi in some cases prove troublesome. 
For this purpose you employ a little instrument of glass named 
a tucker or a dropping tube. It consists of a glass tube,, having a 
bulb in the middle, and one end drawn out to a point. Tnis 
instrument should be twice as lat^ as the figure. You put the 



narrow point into the liquid, apply your mouth to the upper 
end, and suck the liquid into the bulb ; you uien close the onnce 
of the tube wiUi your tcmgue, remove tne point <ff the tube into 



^ motlieT veesel, and then, by opening the upper end 
' of the tube, permit the liquid to drop out. You muat 
take particuW core not to suck the liquor into your 
mouth, becaofie, if it happen to be oil of vitriol or cau- 
stic potash, you may find the taste to be unpleatant. 



Tubes of this kind are commonly mode by the 
^asB blowetB too narrow in the beak — too capillaTy, 
The effect of this is to prodoce a desree of Mctipn 



which makee it tionbleoome to eet the liquid into, 
and out oi, the tube. 1 find it oetter in most casoH 
to employ in the removal of tests, and other small 
qnontitieiB of fluid, a tube of the fi>rm andiize of tbe 
figure in tbe maivin. 

A narrower tube acts too much by capillary at- 
traction, and does not answer the purpose so welL 
The point should be merely a little contracted, and 
not i&awn out into a capillary tube. 

In using such a tube m testing, it is seldom neces- 
sary to suck vrith the mouth. On dipping the tube 
into the test a portion enters, more or less of it ac- 
cording to the depth of the dip. As much as may 
be required is allowed to enter, and is retuned by 
applying the finger to the top of the tube — and just 
as much as may be wished m allowed to drop into 
the solution under examination, by a partial or com- 
plete removal of the finger. 

A modification of thiB methijd of applying tesU by 
dropping tubes, may be advantageously employed 
where a large number of students in a class are fur- 
nished with solutions for analysis, and are all to 
apply the same teats to their sohitions. 

Two ounce bottles should be provided with large 
and good corks, perforated and 
fitted with pieces of straight glass 
tnbe of tius width: 



and so long as to rise half an inch 
above the cork, and to descend 
.nearly to the bottom of the bot- 
tles. The lower end of the tubes 
may be a little contracted. The 
tests are to be pnt into these bot- 
tles, and the tubes used to remove 
them as required. The cork 
must stand so high above the 




bottle as to f>e eosilv' canght by the thumb and middle finger of 
the riffht hand, while the forefinger is left at liberty to close or 
open ftie upper end ofthe tube, as may be required. Theteatsare 
under complete control in this apparatus, so that any qiiantity 
which an esperiment may demand can be administered with foci- 
lity. When a very small quantity ofthe re-agent is required, you 
lift the tube without closing tts upper end. It then acts like a rod 
and t^es up only a drop or two. When you wont a larger quan- 
tity, you lift the tube out of the liquid, close the upper end by 
your forefinger, pluace the closed tube into the liquid, and re- 
move your"fmger. The air in the bottle then presses the liquid 
up the tube conaiderably higher than the level in the bottle. 
. Of course these bottles cannot be used for the conservation of 
solutions that spoil on eTposnre to atmospheric air. They are 
recommended for no such purpose, but for the saving of time 
in cases where students in large elasiei may be engaged in che- 
mical analysis. The operation of atmoq>heric air upon the solu- 
tions can nevertheless be partially hindered by closmg the upper 
end of the tubes with amaU corks, when they are not in use. 

The number of bottles to.be fitted up in this manner for the 
use of a class, must be regulated by the number of tests required 
for the purpose in view. Where testing, according to " Tables of 
Tests,' is practised, there must be a bottle for every re-agent 
which is embraced in the Tables. There will, therefore, be a 
correspondence between the number of test bottles and the 
number of t«flt glasses to be provided, and the seme motive 
which has induced me to recommend the frames for test tubes 
o be made with exactly bo 



me also to recommend the 

5 reparation of a &ame »■ 
apted to hold the requisite 
number of test bottles. No- 
thing answers better fbr this 
purpose than an imitation of ' 
the domestic cruet stand, 
which may be made of a 
piece of board an inch thick, 

pierced with the proper number of holes, of a size adapted to 
hold the bottles, and bottomed with a thin slip of wood, to keep 
the bottles frota fellii^ through. A wooden rod, half an iach 
thidc, and 8 inches long, screwed into the middle of the lK«rd, 
serves as a handle. A glance at a test stand of this sort, previous 
to the commencement of a lesson, shows the teacher whether 
the tests which he purposes to use are all at hand, ready to be 
applied when requisite. 




I,, Google 



FRBCIPITATICN. 



PRECIPITATION. 

WtiEN two limpid solutions are mingled together, and chemical 
action la excited, the whole mixture often becomes tuiUd, and 
B. Bolid powder, in a state of extreme division, fells to the bottom 
of the Tes9eL This powder is called a fyrecipilate, the ^eot emr 
ployed expreaslj to produce it, is called a precipitant, and the 
operation which caus«« its prodnction is c^od precipitatitm. 

Precipitation is extensively employed in analytical chemistry. 
In qualitative analysis it is used to demonstrate the presence of 
certain bodies in solution ; and in qoantitative analysis it is em- 
ployed to separate the bodies contained in a solntioa fiom one 
another. 

The TEBsels best adapted for precipitation in qnalitatiTe analy- 
sis bsve been already described. (Page 49 — 55.) 

In quantitative imalysiB, where the precipitates are often of 
considerable bulk, the best veaaels ibr precipitation are plain 
cylindrical glasses, such as the confectioners glass. Yon may 
1 2 3 also use veagels like those figured 

in the margin. They should be of 
varions sizes. It is useful to have 
a few with the edges ground 
smooth on a stone. These can be 
dosed air-tight by the application 

XII I \ of a piece of ground pSate-glaaa, 
A J \ which is very necessary in certain 

operations, where the exclusion of 
atmospheric air is indispensable to the success of the operation. 
The confectioners' glass above spoken of, is a simple glass 
cylinder, free from any kind of ornament. Common tumblew 
frequently answer for precipitation, but these 
vessels, which ai« taller than tumblers and of 
thinner glass, are preferable. The name 
here given is that by which they are known 
in the glass houses. Tumblers are generally 
too thick at the bottom, and on this account 
are liable to break when suddenly heated. 
The annexed cut exhibits the form of the 
confectioners' glass, but is drawn too wide in 
proportion to its usual height. The stndent 
Aionld be provided with giamea of this shape, 
cqiable of^ holding from a (fuart down to sn 
omice. Those which contain two ounces are 
very useful vessels, as also are those which are capable of hold- 
ing half a pint. Plain cylinders of this sort are also useful in 
experimenting with gases, and under the head of "Manage- 
ment of Qoses," I shall describe a cheap set of small cylinders, 
equally adapted for use in precipitation. 

Of the three jnrs figured in outline above, the first, marked ], 




PRECIPITATION. 61 

is dueflj used on the lectara table id consequence of ttie ele- 
gance of its shape. It has no qoality which facilitates precipita- 
tion, and, inde^, its shank ana foot ore objectionable, as also is 
aU manner of fluting or ornamenting. The second jar (2) is of 
the shape that fedlilates testing on small quantitioi, but which 
hinders precipitatioa, or rather prevents the depositioD of m^- 
pitatM. The third figure (3) represents a form of vessel, better 
adapted than any of the otWrs for promoting the separation of 
prec^tates from the liquid in whicn they are produced. This 
Tariety of the jar is commonly called Phillips's precipitating glass. 
Anotoer representation of this jar is given under the head of 
" nLTUTioH," page 71. 

Precmitatioa is sometimes promoted by the presence of alcsli 
or acid m excess. This depends upon the properties of the par- 
ticular anbatoncea which are operated upon. It is in general 
promoted by agitation, and stiQ more by heat. Precipitation 
effected in hot solutions gives a coarser powder than that effected 
in- cold solutions, and one which, consequently, is leas liable to 
go throng the filtering paper with the liquid, When the applj- 
CBtiMi of heat is aWlutely nece»ary, the operation is sometimes 
best performed in a porcdain or platinum capsule, or in a Flor- 
ence flask. Occasionally, the solution is first heated, and then 
mixed with the precipitant. In other cases, the solution is 
warmed after the precipitant is added : this is done to make the 
preapitate fall down properly, and become fit for filtration. 
BoeK, in his " Manual of ATtalytical Chemittry' describes parti- 
cularly the cases in which the one or the other of the above 
methods is to be followed. The pres^ice of vegetable matter in 
metallic solutions often hinder the formation of precipitates 
which would otherwise be produced. For precise information 
on this point, I refer you to Rose's book, cited above. 

If you have a sube^nce in solution, and wish to precipitate it 
entirely, you may proceed as follows : — Add a small quantity of 
the precipitant, mix it well with the solution by stirring it with a 
glass rod, and then allow the whole to settle. As soon as the 
upper put of the solution has J>ecome clear, add a single drop of 
the preci^tant. If thia causes a troublii^, add a little more of 
it. Stir the whole well together, allow it to settle ^ain, and 
then test it afresh with another drop of the precipitant. Proceed 
thus until the addition of a single drop of the precipitant causes 
no opalescence in the supernatant liuuid. Towarua tlLe end of 
the <n>eration, the precipitant should be in a dilute state, pro- 
vided it be of importance that no excess of it should he added to 
the tolutiiKi. It is extremely difficult to hit the exact point of 
neutr^isation — to add precisely enough of the precipitant, with- 
out adding too much. In general, precipitation is roost com- 
pletely emcted when a slight excess of the precipitant is added 
to the solution ; though the effect sometimes produced by adding 
an exceae of the precipitant is the re-solution of the precipitate. 
When, however, the precipitant is che^ does no barm to the 



63 PKICiriTATlON. 

precipitate, and is not iajurioiu to the resnlting Mlatioii, it is 
advisable, rather to effect the precipitation by adding an exoei^ 
than to lose time by delicately attempting to effect an «xact 
neutialisatlon. 

To provide against the neceaaty of tnnriemng a solution from 
a jar in which it mw happen to be held into another veaeel for 
the mere purpose of heating it, hv which transferring a chanoe 
of losing a portion is introduced, the Genoan chemists use a ves- 
sel that is adapted not merelj' for holding a. cold solution, but 
also for heatmg it in. The form is represented 
in the margin. It is a cylinder of the propor- 
) tions of the confectioners' glass, but made of 
ver^ thin glass, both sides and bottom, and 
having the upper edge curved outwards. The 
thinness of the glass enables it to stand con- 
siderable and very sudden changes of heat 
withoot cracking. The form of the mouth 
qualifies it for pouring without loss. When a 
solution is to he warmed, the glass is placed 
either upon the sand bath, or the hot iron- 
plate of the lamp furnace. 
Glasses of this description (Beaker glattu), made of hard white 
glass, are now imported from Bohemia, and may be purchased 
in Glasgow of the following dimensions. 
The measurement is t^en across the centre of each ve»el : — 
So. 1—3 by Ik bchH I No. 6-^ br 31 iuchco 

a-3i „ 2 — ^-.^ „ 4 — 

a—t „ 3i 8—8 „ M 

4—6 „ 9t 9-9 „ G 

5—6* „ a I 

The price of the DCM of 9 Jin No. I to 9, ii 16<. 

6 Jan.- No. I to 5, ia bt. 
3 J4II No. 1 to 3, ia :2b. 6d. 

'Wlien English glass makers can be persuaded to make ves- 
sels of this kmd, or rather when the Bntish government pleases 
to permit the manu&cture of chemicftl vessels ia Britain, they 
may become cheaper. The freight of these vessels from Bohe- 
mia, and the enormously high English custom house duties consti- 



tliat the nature of that material vrill not ulow it to he blown 
sufficiently thin. 

Bebzbuvs usee for precipitation, as well glasses of this sort, as 
of a sort neariy the same as this, bat blown wider at the bottom 
than alove, so as, in some degree, to resemble the precipitating 

i'ars recommended by Mr Phillips. Jars of this Aspe are much 
ligher in price than the jars which are widest at the upper part; 
because, as they do not ne«i (pack one within another), they 
cost more for carriage, break^, warehouse-room, &c, than jais 
of the common kind. It is tBis circumstance, probably, which 
prevents their general adoption. 



FILTRATIOM. 63 

Since page 60 waa printed, I have i«eeiyed the plain eylindei's 
. idladed to at the foot of that page. Thesizesandpricw of these 
are « A^wb: — 

Ns. 1—3 bv 11 incbe*, price Sd. 

a-3„ II ■ 6d. 

S— » „ 3 7i. 

4—6 - 31 8d. 

The 1 cylinaen in a neat, price 3a. 
These cylijidera are not only usefhl to students, but are well 
odqited for many analytical operations that are practised in the 
laboratories of manufacturing chemists. 

EXERCISES AND CLASS EXPERIMENTS. 

Chiuccal MlLlctl! TiBO limpid liqaori coniieTted by mixlitrt into a 
toUdmati. — I. If* utnratcd lolutioD of cliloridc of calciain be mjied witK 

liqaidi, tbt rault ii the fonnitioB of in opaqus ud ilmiat lolid raui. 
MbIdiI dMMDpoulian of th« ultg tikes pliua — chloride of potiaium and 
carbonate of lime Mia ibrmed; and the latter, being a bulky aolid, abaarba 
the vhJide of the water of aolutioa, and thua prodncel a de|[ne of aoliditf. 

S. Drop aulphuric tcjd into aiaturated aolution of chloride of caleinm; 
in thi> case alao an opaque maaa ia produced. The chloride ii deoompcMd, 
and eulphste of lime, a highly insoluble aalti ii formed. 

8. Pour a aatnratBd aolution of cauatic potaih into a aaturated adutiou of 
anlphate of n]^;ii(«a (Epaom lalt). A naaily aolid maaa it again ^rodueed. 
The aulphuric acid le>*ea the magimia (irluch then Bombinea-with water 
and ia precipitated in the form of a white powder) in order to combine with 
the polub> 

4. If a little nitric acid be added to the product of jmweu I> the »lid 
mast will be converted into a tranapareat liquid; the inaoluble carbonate of 
lime being converted into the aoluble nitrate of lime. 

G. The precipitate! afforded by the foregoing operatiotu, ahosld be aepa- 
rated from the liquidi in which they art formed, by the methods to be da- 
tailed in the fudlowing articles on "riLTUTioij" arid "iDULCoaaTioN," 



FILTRATION. 



When & solution has teen prepared for esamination, it ought 
to be perfectly clear. If it appears inuddy or troubled, it must 
be submitted to fiUratUm, tbat ia to say, it muat be passed 
through a paper filter, by which meaiia it is sepanttad ^m the 
solid meters wtiich make it appear opaque. 

In like manner, when a predpjtate is to be separated from a 
solution, we resort to the aame procesa of filtration. In short, 
this operation ia the one which occuis in chemical analyias 
oftener than any other, and the one xxgoji the proper execution 
of which, depends a good deal of the success of the analyst. I 
need scarcely, therefore, make an apology for describing this 



! . * 



64 

operotioii at leiip|tli, or fbr pointing' ont with pi«<^ion the 
various sources (K[ error, and the means by whicn they am be 
obviated. 

The operation of filtration consists, generally speaking, in 
ponring- B troubled liquor into a filter or cone of porous paper, 
so arranged as to let the liquor pas? in a clear state, and to retain all 
the solid matter. The things which we have to consider, there- 
fore, are these: — 1. The way to fold the paper into a proper 
form. 2. The shape of the funnel adapted to hold the filter. 
3. The means of supporting the funnel with its filter. 4. The 
way to pour the whole mixture into the filter, and to collect all 
the clear liqwor which runs through it, and all the soUd pre- 
cipitate, without loss. S. The quality of the paper fit to be 
made use of foe filters. 

HOW TO FOLD FILTERS. 

To form & filter, yon are to proceed as 
fi)llow9. Take a piece of filtering paper 2J 
inches square; fold it in hal^ so as to 
bring the comers c d upon the comers 
a b; then fi>U it again, so as to hring the 
four comers together at a; cut off the 
corners, so as to form a quadrant, in the 
manner shown by the dotted lines in the 
under figure a o; and, finally, open the 
first fold, by separating the quadrant b 
from the other three quadrants, so as to 
produce, o, an inverted hollow cone. 
The letter o points out the position of 
the centre of ttie paper in all tlie figures. 

PROPER SHAPE OF FUNNEIS. 
Procure a glass funnel, of the form of the annexed figure, 
and one and a lialf inch in diameter. This is large enough to 
hold mauy [o^cipitates which occur in 

?[ualitatiTe analytical experiments. But 
ai^r funnels are also necessary,and are to 
heofthesame fi>rm. They must always be 
made of glass. The paper filter, folded in . 
the manner described above, is exactly 
formed to fit a funnel of this shape. The 
filter, when placed within the funnel, must 
not come within an eighth of an inch of 
the top, otherwise the liquid which may 
be poured into it is liable to run over, or, 
at tne least, to evaporate and leave a por- 
tion of salt on the very edge of the paper, whence it cannot 
easily be washed back. There should be no loose places be- 
tween the paper and the glass, no wrinkles in the paper, nor 
any fold or orifice to give passage sidcwise to water that is put 



V 



upon any wlid matter trtiich the filter may contain. English 
fanoek are generally made narrower and longer than this figure, 
and such flinnela are objectionable. But it is possible to remedy 
in Bome degree the defect in their shape, hy folding the double 
part of the filter after it is brought into the form o, one fold 
over the other^ until the filter forms a narrower cone than one 
of which the Hides make an angle of 60", int« whicli form the 
filter is thrown by simply foldina; the paper twice across. Fun- 
nels of a proper form, and of all neceeeary sizes, are now how- 
ever kept for sale in Glasgow, at moderate prices. The best 
way to test the proper shape of a funnel is t« cut a card intc an 
eauQateral triangle, and examine whether the aides of it fit the 
ndes of the funnel into which it is inserted. When a funnel is 
of the proper form, its perpendicular section represents an equi- 
lateral triangle. Consequently, a card cut to this shape, with 
sides equal in lenffth to tne diamet«r of the mouth of the funnel, 
should turn round in the funnel and touch it on all sides dike. 
The neck of the funnel should descend 'from the wex of the 
cone, nearly of a cylindrical form. The most useful sizes of 
funnels for analytical experiments, are the tix following, the 
four smallest of which are beat adapted for qualitative analysis, 
and the others mostly employed in quantitative analysiB. The 
funnel marked No. 1, is made with a very narrow neck, that it 
may serve the purpose of a filler for small vessels (page 16): — 
Silt* of Fnnneli. CiuuelcT of the mouth. 



Equilateral' triangles of card, having sides of theee lengiths, 
should exactiv nt the respective funnels. No intermediate 
sizes of funnels are nece»»ary, nor, for reasons that will appear 
in the sequel, sAouU be admiltetl into a laboratory. 

HOW TO eUPPOET FUNNELS. 

The simplest method of supporting the funnel i 
to place the neck of it tbrou^ a hole made in th 
middle of a piece of thin board, laid on the top of i 
the glass cyflnder which is intended to receive 1' 
filtered liquor. 

The hole in such a board must be conical, ._ 
larger on one side of the board than on the other 
side, in order to suit the shape of the funnel. The 
board should be ^ inch thick. The hole may be 
I inch wide below, and If inch wide on the upper 
side. The triangular card serves to measure the pro- 
per angle of this hole, as well as of the sides oftbc 
nmnel. Thin polished circular mahogany boards, 
with holes in the centre, imported from Germany, 



♦ 



66 



FILTBATIOM. 



are now to be hoA in Qlaagow, of various diameten, as ore afao 
circular plates of slaas perforated in a similar manner, and grotiiid 

smooth on the edges. 

When the acceea of atmoapheric air ia to be aroided, aa in the 
filtration of solutions that contain lime, alcohol, &c^ the funnel 
must be covered with a plate of glaM, and if the air is to be 
utterly excluded, the edge of the funnel and the aur&oe of the 
glass plate must be ground m as to fit air tight. 

Another method of support- 
ing a funnel, is by means of a 
ring of wood fastened to an up- 
right stand, and capable of being 
raised or lowered at pleasore, 
like the ann of the biangle re- 
tort stand formerly described. 




ed in the margin. The ring, oi 
orifice, in the arm a is cut coni- 
caUy, BO that the inner sides of 
the aole exactly fit the sides of 
the funnel, and consequently 
hold it firmly. The screw b 
serrea to raise or depress the 
funnel according to occasion. 
This is the fumiel holder em- 



ployed by B 
^Vhon the upright rod of this filtering apparatus is made 



square instead of round, it i 



poauble 

A, 



.^ 



fasten the arm which 
holds the fdnnel, by a 
small wooden wedge 
instead of a screw. 
This improrement is, 
'« I beUeve, due to Pro- 
fesoi Qraham. The 
instrument can then 
made at a lower 
price, and thus con- 
structed, it ia, in foot, 
now sold in Glasgow, 
complete, for eight- 
pence, lite apparatus 
fumishedfbruusraaall 



_^,fea 
— '* 1.™ 



nels abore-menti<Hied. 
Thefignre in the mar- 
gin ebovn the method 
ofu^git. aisthe fen- 
nel which contains the 
filter; i i, the arm to 




-RUmATIOK. 67 

bold thefonnd; e c, the sqnanupriglit Tod to iupport it ; d <^ tile 
wedge to fasten Uie arm to the nid. Whenever tne arm is Kqnir- 
ed to be moTed hi^ier or lower than the pomt st which it may 
happen to be fixed, it can be instantly loosened from the rod by 
- pushing the wedge d d a Ettlo Dpwanls. The riiape of the arm ra 
mat seen in the following figure, where F ahowg the place for 
the fiuinel, the two concentric drclea around which refveeent 
the upper and nnder edges 
'Of the orifice, and where r 
. ahowB the place for the rod 
e c, and «, the place for the 
wedge d d. I Save recently 
improved this funnel holder 
by making the arm, F r (r, 
of glaxed tarthenviare instead of wood. The arm is abont four 
inches in length, and the hole F is one inch wide on the nnder 
toAe. It holob swly any of the ftmnels enumerated at page (m. 
It is easilv kept clean. It can be used with filters of a small 
size to Ji/Cer viithovt a funnel, since the cwiical sides of the ori- 
fice not only hold the paper securely, but are not liable, if kept 
clean, to communicate any imparity to it. Finally, the cost of 
the ^puatuB, conrasting of China arm, with wooden rod and 
foot, is only one ehiUin^. 

I expect in a short tmie to receive fWim Berlin, some of the 
arm fonued of porcefain. 

THE ROUTINE OF FILTRATION. 

SIf yoo pour a turbid liquid into a dry filter, the first portion of 
uid which passes through has generally to be re-filtered, being 
en slightly turbid. But when uie fibres of the paper are swelled 
by moisture, the liquor passes through in a transparrait state. 
It is a good plan ta provde agmnst tli^ necessity of twice filter- 
ing by moistening the filter with distilled water before you 
b^in to pour in the solution. This enables you t« fix the filter 
neatly in the tunnel, and by preparing the paper, hindeta the 
passing through of any turbid hquor. Moreover, it prevents 
the precipitate from being partially fixed in the pores of the 
ptq>er, wtuch sometimes happens when a turbid liquor is poured 
inb> a dry filter. This method should ther^re be followed 
Invariably. The- small quantity of water necessary for the 
purpose of wetting the filter can be conveniently supplied by 
the washing bottle. The manipulation is as foHows. Von 
arrange the funnel holder, the fiinnel, and the glass that is 
to receive the filtered liquor. You fold the filter, open it, and 
catch hold of it near the top with the tip of the thumb and fore 
finger of the leil hand, appQed at the angle between a and o, in 
the small figure on page 64, in such a manner as to press the 
loose outside fold of the paper against the cone. You place 
the filter m the funnel, and ret^n it in its proper dtnation, by 
prceeing it slightly wUh the tip of the forefinger. Yon then 

.. Cooglc 



68 nLtiukTioK. 

take ttte wtwhinK bottle in jour right hand, blow aix into it with 
your mouth, and direct the alight jet of water which igsuea&CHn 
the tube, orei the whoJe suriace of the filtet. The latter, when 
thuB wetted, wta steadily in its place. 

When the filtering ^paratua is placed together in the mail' 
!i shown hy the wood-cuts, and Uie filter naa been properly 



prepwed, the liquor to be filtered is to be decanted into the 
paper, with the help of a rod, as deacribed in the fiillowing ar- 
ticle on "DecuitatioD.' The liquor should never be permitted 



o rise quite to the top of the paper filter, otherwise it will 
escape between the paper and the glass, and then run down into 
the clear liquor, contaminate it, and oblige you to perform the 
whole operation over again. The fuUer you keep the filter, 
however, the quicker the filtration proceeds. Keep it therefore 
nearly full, but do not let it run over. 

It is proper, in quantitative experiments, to let the point of 
the funnel touch the inner tide of the vessel in which the filt«red 
liquid is collected. The method is repiceented in the cut ex- 
hibiting Berzelius's apparatus. This prevents the aplashing 
which occurs when the point of the funnel is fixed in the centre 
of the vessel, and at a distance above the collected fluid, as it is 
represented in the last cut. It is poaaible when this preoau' 
tion is not observed, for part of the liquid to splasit out of the 
vessel. The jar which receives the filtered liquid can be pro- 
tected &om dirt by a plate of window glass, having a bit cut 
out at one aide to allow room for the neck of the funnel. In 
using a joT with straight sides to receive the filtered Uquor, the 

Ct of the funnel is to be brought close to the side of the jar. 
:y drop which &1Ib from the funnel is then attracted, duridg 
its f^ towards the side of the glass, which it touches before 
reaching the mass of liquid below, and consequently produces 
no splashing by its plunge. 

If the Boud substave to be separated by filtration, needs to 
be weighed, it is necessary to ascertain bdbrehand the we^ht 
of the filt(X. To this end, the paper after being cut to the 
proper size, is folded small, put into a counterpoised crucible or 
glass tube, and exposed to the heat of a sand or water bath till 
it ceases to lose weight. Its weight is then determined, and 
marked upon it with black chalk. But if the powder that is . 
tOi4>e weighed needs to be ignited aAer filtration, then the paper 
may be burnt with it, and the Ahes of the paper weighed with 
tiie powder. In this case it Is only neccesory to know now much 
ashes is left by a burnt papei' filter of the same size and weight 
in order to be able to deduct &om the weight of the igmted 

Kwder, the amount of the ashes of the filter. This subject will 
recurred to at the end of this arGcle. 

If you wish to filter broth, or any mixture containing animal 
matters, first run it through muslin, or a linen cloth, to clear It 
from the heaviest part of the solids it cont^ns, and filter it 
tlmtugh paper afterwards. 

l:,<,,i,.-^i I,, Google 



Strong acida and concentrated alcoUne liquon cannot be iU- 
tered throiigh paper. In general they can be best separated 
from impurities by decantfttion, (See " Caustic Potaah.") They 
can however be filtered throngn a funnel filled with pounded 
glaas or clean sand, a few larger lumps of glaas being put into 
the neck of the fiinnel. Alcoholic solutions should be filtered 
under a bell glass, that the eTaporation of the alcohol may be 
hindered. Should a bell glaaa not be attainable, the neck of 
tlie funnel must be stuck into the mouth of a flask, leaviiw only 
a Email vacancy for air to escape; and the mouth of theninnel 
must be closed by a ground glass plate. 

DECANTATION. 
1 wish to remove a liquid from a solid which hss 
r when yon want to pour a liquid from a wide 
mouthed vessel into a narrow mouthed 
yvessel, or from a solution flask into a 
f filter, yon may proceed as follows ; — Ap- 
ply a Uttle tallow to the edaie of the large 
vessel, dip a glass rod into the liquid, hold 
the middle of the wetted glass rod against 
the tallow and then by inclining the large 
vessel, make the liqmd nm gently down 
the rod into a vessel placea below the 
point of the rod to receive it. The tallow 
prevents the liquor from mim ing down the 
outside of the lai^ veeael. You must per- 
form this operation without losing a single 
drop of the liquid. To prevent a loss by tplaihing, the lower 
point of the rod may be made to touch the inner side of the 
Teasel into which the liquid is to be poured. The act of pouring 
from a cylinder is greatly facilitated when the edge of the glass 
is bent outwards, like that of the Beaker glasses depicted at 
pages 62 and 66. In decanting into a filter, it is a rule to let 
the stream run against the inner side of it, and not directly down 
the middle into tno apex of the cone. When the first quantity 
of liquor put into a filter has run through, and more is to be 
poured in, it is particularly necessary to take care that the 
stream does not fall into the centre of the filter, as it would be 
almost certain to cause a qilashing sufficient to throw drops of 
the liquor entirely out of the funnel. This is not so much to be 
feared when the accumulating precipitate has formed a round 
mass at the bottom of the filter. 

When the vessel which contains a liquor to be filtered, hap- 
pens to be veiy*full, it is nearly imposmble to pour from it into 
the filter without spilling a portion. It is proper to avoid this 
loss, by transvasiog some ot the liquor by means of a spoon of 
platinum or porcelain, which can be afterwards washed from it 
Dy the " wasning bottle" described in the next section. 
If the sediment from which you desire to decant a solution, be 




M liabt as to mix readily with the liquid when the vewet is 
ffentlv moved, it la necewoiy to draw off the liquid without mov- 
iDg tne veaseL The following figure exhibits an inBtnimeDt 



=F 



which is veiy useful in such a cose. The pari b may be three 
or feur inches long and nearly an inch widp, the part a four 
inches lonK> and the dcsoenoing part c, eufficientlv long to 
reach the bottom of the veaael from which the liquid ia to be 
withdrawn. In applying the instrument, you d^ the point c 
into the liquid, and then, by applying the mouth to the upper 
end ^ you Hack the liquid into the reaervoir b. When the liquid 
is smaU in quantity, the sucker, or dropping tube (page S8) may 
be used to remove it. 

HOW TO FOLD ElBBED FILTERS. 

When you widi to filter a liquid rapidly, to 
. free it from impnrities, it is sometimes proper 
to employ a ibided or ribbed filter, like the 
aonosed ^nre. To form this filter, you pro- 
ceed as follows : — Take a square piece of paper, 
fold it into two, by doubting the comers o d 
upon the comers a 6, as directed at pag« 64 ; 
then make the folds ^own by the annexed diagram, and let them 
all bend on the same ride of the paper. To produce 1 to 6, fold 
< a • I s 10 upon 2; to produce 1 to 8, 

fold 10 upon 6; to produce 1 to 
9, fold the Ime 1 t^i 10, upon the 
line 1 to 8 ; to produce 1 to 6, fold 
^ 2 upon 8; to produce 1 to 4, fold 
2 upon 6; to produce 1 to 3, fold 
2 upon 4; to produce 1 to 7, fold 
10 upon 4. You have now 7 folds, all on one wde of the 
fopet, namely, folds 3 to 9. N«st iqake a fold between each qfthe 
above foldi, so as to risQ on the other side of the paper. B^^in 
by folding 1 to 10 upon 1 to 8, and turn back 1 to 10 upon 1 to 
9. Yon i*ill thus produce the reversed fold 1 to 11. Proceed 
in the same way to make a reversed fold between each of the 
other folds. When the paper is folded np, it looks like a chUd's 
fan. Cut off the projecting parts, so that the paper may look 
like a circle if opened out. Gently separate the two sidea of the 
filter, and form it into a little cup. Put your finger into the 
cup, and pitoh out the bottom till it is round. Cpon examining 
the opened filter at the parts marked 10 and 2, yon wilt find that 




riLTBATtOK. 71 

tiiere an two folds bending the same way. Tliiedefeet you cor- 
rect by mttking a nnall additionsl revened fold in the porta 
which lie between 10 and 11, and 12 and 2. In mbbing down 
the folds, do not rub the paper near the centre 1, otherwise you 
will produce a hole. The fiinnel best adapted to contain a folded 
filter, is higher and narrower than the funnel figured at page 64. 
I cannot recommend this ribbed filter to be employed in any 
case where a precipitate is to be washed, for the mi^tiplidty of 
its folds produce so many receptaclee in which the aohd matter 
can hide, that it is nearly imponible to cleanse a precipitate 
contained in such a filter entirely from the mother liqiior. The 
ribbed filter was an improvement upon the method used formerly 
and still recommended by some persons, of promoting rapid fil* 
tration by making ridges in the funnel, or by potting glass rods 
or straws between the fdnnel and the filter ; but coutrivancM 
of this sort are seldom of anv nse, and are often prejudicial. 
The best way to secure rapid filtration is to procure good filter- 
ing paper, 

HOW TO FILTER WITHOUT A FUNNEL. 

As it is often deurable in qualitative analysis to filter through 

Tery small filters, and as funnels of a proper size are in many 

places not eaoly procnred, several methods have been contrived 

of filtering without funnels. One such method consistB in placing 

the paper filter in the mouth of a teat glass 

a narrow enough to hold it steadily, such as the 
test glass described at page 54, or in the mouth 
of a small precipitating glass of Phillips's pat- 
tern. The latter answers best, in consequence 
of the greater space afforded for the reception 
-of the filtered Uquor. Paper filters of sofB- 
cient capacity to hold any weight of water not 
exceeding two ounces can be used with safoty 
in this manner. — Another contrivance of the 
same sort is the China fojuiel holder already 
described. Paper cones &«m 1 to 2 inches in diameter can be 
held by it witnout a funnel. The filter described in a nibse- 

aueut page, as " No. 2,' is gripped by this Amnel holder, near 
le upper edge of the paper, in such a manner as to prevent any 
of the liquor which passes tlirough the filterfrom lodging on the 
upper Burfiice of the china arm. But when a larger filter than 
No. 2 is used, some of the hquor that passes through the upper 
part of the filter runs upon the china arm, and thence into the 
vessel below. Hence it is neceasary to keep the china arm scru- 
pulously clean. In consequence, however, of this spreading of the 
filtered liquor over the support, this method of filtering without 
a fonnel cannot be used in quantitative analysis. 

A third method of filtering without a funnel is provided by 
the filtering ring of Professor Clark oi Aberdeen, which is repre- 
sented by c in the following figure. 



TILTRATION. 




This is formed of glasB rod, preciady of the size here depicted, 
and provided with three anna of the length denoted by x k x. 
The end of each arm U furnished with a little peg or knob as 
shown at a, A smaller size of this ring is represented by 6. 
It should be made of thinner rod than the larger ring, but its 
arms should extend, like those of the larger ring, as fei aatmder 

as the points x x x. 

In use, these nngs ate dMosed in the 
: manner shown by the annexM cut, where 
X K X represents a filtering ring placed on 
the tOTi of a test glass, and o a p^>er filter 
fixed m the ring. The pegs or loioba a at 
the end of the arms x s x serre to keep the 
ring from slipping off the glass. — A filter, 
placed in a ring of this sort, can be filled t« 
the brim without loeine; its shape or suffer- 
ing the liquor to ran down nnflltered, pro- 
vided the paper is of good qnality. 

»„«„ ^.~. gs could probably be made of white porcelain 

or cast glass. They should be flat, | inch thick, the inner side 
of the ring conical having the side inclined at an angle of 60°. 
They would then grip the paper cones firmly. The apertures 
dionld be ^ inch, and 1 inch acrow below. These are the most 
useful sizes. The bodv of the ring might be J of an inch thick, 
and the outer part a little rounded. It shoold have two flat 
arms, fixed to opposite sidee of the ring. I give these propor- 
tions from wooden models of such rinra, which I have tried. 

Filters held to these rings allow flie liquor to pass through 
them with rapidity so long as they are kept pretty fiiU, but 




These filter ri 



MLTUnoN, 73 

they do not filter with rftptdity to the end of the operation; 
on the contrary, a small quantity of the liquor remaiuB long in 
the filter, and keeps the predpitste wet for some time after it 
would be dry, were a funnel nsed to hold the filter. The rings 
cannot be uacd, thereibre, when a precipitate requires to be 
washed clean. They are chiefly oseftil wnen a liqaor is to be 
quickly cleared Irom solid matter of no nse, and where it an- 
swers tlie purpose in view, if the Rceater part of the liquor is 
readily got in a clear state, Blthough a portion be loet. Thus, 
'n exercising a class of students in qnoUta- 
ive analyaiB, wherein the filtration (^ small 
quantities of liquor occurs prettr frequent- 
ly, as in the preparation of solutions, the 
separation of precipitates, and otherwise, 
these rings, supported upon conical test 
glasses, answer a good eni£ 

A still simpler method of filtration ean 
he occamonally employed in rough experi- 
ments. Suppose a solid substance to have 
been found oy previous experiments to 
be soluble in nitnc acid, but that it is de- 
sirable to know &rther whether its solu- 
tion in that acid is precipitaUe by one or 
two particular teats. You dissolve the sub- 
stance, e, in nitric add, /, on a slip of glass, 
ab e d,ae directed at page 14. When th.e 
solution is effected, you ^laco on the glass a 
triangular slip of nltenng paper, g, with 
one side parallel to the solution and very 
near it. You then hold the end,a6,ofthe 
glass uppermost, and so cause the solu- 
Xitta,/, to flow over the filter down to A, 
the other end of the slip of glass. It is 
thus rendered clear, and can now be di- 
rected by a glass rod to two or more sepa- 
rate p<nnts, to be tested with different re- 



CulTiNO OP FiLTBES. — Wherever filtration has to be often per- 
formed, it is convenient to have papers ready cut in sizes to suit 
the ftmaels in most frequent use. This convenience is more 
especially felt when a number of persons are working ti^ether 
— ^for example, a class of practical (medical) students. If the 
filtering paper is kept in whole sheets, and not in sizes, there is, 
in the latter case, no end to the loss of time, and waste of p^ier, 
which is the infalHbte result of permitting or causing the stu- 
dents to cut filters one by one from whole sheets of paper. 

I have recommended ^age 6fi) that funnels be kept of obtain 
regular sizes. It is equally expedient that there should be kept 
a supply of filtering p<^r cut mto pieces adapted for these par- 




TILTBATIOir, 



ticnlai foimeU. I will add here s tabular view of the taxea of 
sqimrea of paper adapted for such funnels as are found to be of 
moet frequent use to peivouB engaged in chemical analysis. 



No. of the 


Diameter of 
theftmneb. 


Square of paper to 
measure at each ride. 


6 


It inch 
11 

3 

31 

4 


2) Inches 
7i 



These squares of paper on beii^ folded twice, and IiaTing the 
comers removed by scissors or otherwise, (page 64) so as to 
leave a circular disc, produce cones that exactly fit fonnels, 
the sides of which diverge at an angle of 60°, and that in all 
cases fill the fannels whose rizcs are given in the table, except- 
ing B space of ^ of an inch at the top. 

1 have, at page 64, described the method of folding filters, 
but I have yet to describe a contrivance by means of which the 
filters, when twice folded, can be cut into uniform qusdranta with 




fiicility. The above figure repreeenta the nzes of four quadranta 
of tin plate, which can be nsed to goide the sdssors in cutting 
off the comera of the paper when folded. They are lulapted 
in size to the four amallegt filters described in the above table. 
Every tin qnadiant is kept in a little box with the square of 
paper to wUch it is adapted. 
A still better method than this of cittting filtcn has been 

„Go.,glc 



riLTRATIQN. 75 

recently mggeated by Dr Mohr of Coblents, whoae paper (^n- 
tiakn der Pharmacie^ Januar, 1837,} has come into my Danda at 
the moment when this sheet is ^ing to prem. His plan ia to 
employ a quadrant of tin plate, having a rim i or ^ mch high 
along both its straight aides. With this he uaea a second quad- 
rant of such a size that when placed upon the first, and close to 
the straight rims, the outer circular edges of both become par- 
allel to one anotiter. The filters to be cot, first folded mto 
squares, as I have already directed, are put, in tluckneeees of 
five OT six, between the two tin quadrants, and are cut close to 
the circular edge by sheaia. 

CiEctn-iR FiLTEM. — Since the above article was written, I have 
succeeded, after many ineffectnal attempts, in finding a method 
of cutting filtering paper into circular discs, adapted for filters 
to fit the prescribed (page 6fi,) sizes of funnels. The cutting 
maohinenr is simple, but powerful and expensive, and not 
adapted for private use. It consists of an armuig press, worked 
by a lever of considerable power, and provided with a sharp 
circular steel knife for eacn size of filter. It is not there- 
fore a machine for laboratory use, but the cutting is effected so 
easily and cheaply, that, where tlie machinery is at command, 
round filters can easily he prepared, and will now become an 
article of commerce, and be sold at moderate prices. 

In using these filters, they have only to be twice folded across, 
as recommended for the square papers at page 64, when, upon 
being opened up, they present at once a oone of 60° adapted to 
the size and form of a filtering iiinneL 

Proper Pafes fob Filtbrino. — From what is sud above, it is 
easy to see what are the properties of a good filtering paper. 
It should be porotM, that the liquid may run through. It should 
be fmooth on itg rur/ace, tJwt the precipitate may not get into its 

Kres, OT become fixed over a large sumce instead of oeing ed- 
ited at the bottom of the cone. It should contain no aoluble 
matter, else it will contaminate the solutions. It should be thin 
in gviilance, otherwise it will give too much charcoal when 
burnt, and may in some cases act as a reducing power upon 
ignited precipitates. It should give no athes except the small 
portion which is the common product of calcined vegetable mat- 
ter, and which should never be much more than ^ per cent. 

A filtering paper that filters slowly, says BGnzsLnrs, should 
never be used; ftiin filtering and washing precipitates withsuch 
a paper, you lose so much time, that you cannot make the same 
progress m your researches which yon would do otherwise. It 
IS beat, he odds, to bespeak filtering paper for your own use at 
a paper miU. (A Scotch paper maker would hardly thank you 
for such an order.) It should be prepared from a pulp with 
long fibres, and in the winter time, in order that it may freeze 
whUe still wet, whereupon the water betwixt the fibres of the 



76 FILTRATION. 

paper becomea ice, and expsadiug, forces open the pores of the 
paper in all directions. A paper made in this Dunner filters 
much qnicker than one of the same materials prepared in 
nimmer, and deprired of its water by immediate eTaporation. 

Two varieties of filtering paper are recommended by Berzoliua. 
One variety of the thickness of common printing paper, the 
other aa tlun as fine letter paper, or as thin as it is possible to 
be made without hcdes. Iiic fint kind is intended to be used 
for laive filters, and for experiments on unwei^hed quantities. 
The thm kind to be used in quantitative analysis. 

Let ns now see which of these characters are answered by the 
papers that are to be found in the stationers' warehouses, or 
that can be procured from the paper mills, of England and 
Scotland. 

Po»t Letter Paper. — This can be eot free from size, that ia 
to say, in a bibulous state, but it filters very slowly in conse- 
quence of the close texture produced by the very finely ground 
rags of which it is composed, and by the hard pressing, and 
nqiid d/ying, which attend the act of making it. 

Printing Paper. — 1 have never been able to get any of this 
kind of paper unsized. In the manufacture of printing paper, 
as practised in this country, the size is mixed with the pulp 
before the paper is mode, whereas the printing paper made 
abroad is without size, and our post papers are sized after they 
are made. 

PItUe Paper. — All the TarieUcs that I have tried are stuffed 
with plaster of Paris. 1 think it probable that the pulp of which 

flate paper ia made, if nnmixed with sulphate of lime, and nn- 
leached by chloride of time,-made into demy of ISIb weight to 
the i-eam, would make good filtering paper. 

Red Blotting Paper. — The red coloured blotting paper csimot 
be used in consequence of the colouring matter it conttuns. 
Laid White Blotting Paper.— The wjijte kind of blotting 

Kper constitutes the best filtering paper which is commonly to 
procured. It has, however, several defects. It is always 
made with wire marks, and when wet is frequently either rotten 
or it exhibits numerous holes at these wire marks. It is bleached 
with chloride of lime, and frequently is not well washed frum it. 
It scunetimes contains plaster of Paris. It is often much too 
thick, ond too firm in its texture to answer the pui^)03e of filtra- 
tion. However, a thin and tolerably pure article can sometimes 
be procured, which aupplies good filters— but of the white blot- 
ting paper which is usnallv to be found in the shops, not above 
one ream in twenty is of tnis good kind. 

Apotheearie* Filtering Paper. — Two sorts of paper of very 
thick substance, and roo^h surface, formed partly of woollen 
materials, are made for apothecaries' use. One sort is pale 
brown, the other and the roughest is blue. They filter with 
remarkable rapidity, and would be useful in clearing neutral 
solutions from dust or powder of no value; but as both sortsare 



unfit to gather predpitates upon, and as, in rousequence of con- 
taining wool, thev act chemically with solutions containing 
caustic alcalies or &ee nitric acid, it is not advisable to use them 
in analytical experiments. 

Tea Paper. — A coarse cheap paper used by grocere, having a 
browniBh white colour, and known to stationers' by the name 
of smati lioTid, is aometimcB suSciently porous to be used as fil- 
tering paper. It is &ee from lime, and from bleaching liquor. 
It filters, nowever, but slowly; and the sur&ce presents nume- 
rous small bits of straw and wood, which readily come off, and 
mix with the precipitate. 

StBtduh Fitteriitg Paper. — Bcrzeliua recommends S pmer 
that is mode at Grykgbo in Dalame., Sweden, as being made ex- 
pressly for filtering, and as answering the purpose completely. 
It is made, he says, with water so pure as to act upon no foreign 
substance, and waich contains no earths. Acids and water ex- 
tract nothing from this paper, and when burnt it yields no other 
ashes than such as are peculiar to pure linen, and of these not 
above f per cent, of its weight. The makers of this paper, he 
odds, Iwve such fecilities for the manufiicture of good ffltering 
paper as are not easily to be equalled elsewhere, and that in 
consequence of these advantages they have recently prepared a 
quantity of this paper as an article of commerce. He neglects 
to add to this relation, the name of the manufacturer of this 
paper; in consequence of which neglect, it is as impossible for 
the English chemist to procure a supply, as it would be were tlie 
paper mill at which it is made situated in Uto^o. 

1 have, however, procured some paper from Berlin, said to bo 
Swedish, and I find it to be of very exceUenf quality. The sample 
which I received presented O.STfi grain of ashes in the 100.0 
grains of paper. The size of it is that of English small folio 
post. The colour U yellowish white. The surface has a peoo- 
liar soft hairy feel. It filters vrith very great rapidity — a filter 
in a frmnel 2^ inches in diameter, sometimes gives a continuous 
stream of water, but other sheets are closer and filter slower. 

The eqiensiveness of this paper in Germany, the cost of bring- 
ing it here, and the absurd duty of ninepence per pound weight 
levied upon it at our custom-house, added together, make the 
paper too dear for use in this country. It cannot be sold in 
Glasgow under Ss. 6d, the quire. 

Filtrir Seiden-Papter. — A pwer sold in Germany under this 
name, and described there as "fine filtering paper," is of the size 
of English royal printing paper, and in texture resembles our 
tissue paper, being as thin and as full of holes. It contains above 
3 per cent, of ashes, among which is found the colouring matter 
of the paper, oxide of cobalt. It filters twenty times slower 
than the Swedish paper. 

Filtrir Drtiek-Fapier. — This is a variety of printing paper used 

in Germany for filtration. It is made with wire marks and has 

a strong bluish tinge, from the oxide of cobalt which it contains. 

a3 



78 FILTRAIrON. 

It fiIt«T8 r^idly, but it contains 6.88fi or nearly 7 per cent, of 
Mhes. The German paper makers appear to colour their paper 
biDO with Hmalt, inst^d of bleaching it vitii chloride of lime, sa 
is done by onr paper makers. 

From my examination of the last two papen, which Jpmcnied 
from one of the first manufacturers of chemical ^paratos in 
Bkklin, I am led to believe that the German chemist*, with the 
exception of those who procure the Stredish paper, are worse 
provided with good filtering paper than we are in this oonntry. 
The average quality of our thin wire matked white blotting 
paper of commerce ib superior to both these German papers. 

EnglUh Wove Blotting Paper. — Among the varieties of paper 
which have come to liand, while I liave been engaged in the 
search for good filtering paper, is an article that beais a consi- 
derable resemblance to the Swedish filtering paper. It is of the 
size of demy printing paper, was sent to me under the name of 
tchile blotting paper, but, unlike all other sorts of white blotting 
■paper (hat I have seen, it is not wire marked, but tooee and of 
very uniform sur&ce. The colour is whiter than that of the 
Swedish paper, it is of firmer texture, and far less esey to break 
when wet than the Swedish paper, which in that state is parti- 
cularly rotten. It is thicker (heavier) ttion the Swedish paper 
in the proportion of 1Q04 to 154S. It filters slower than some 
sheets of the Swedish paper, but quicker than other sheets: gw- 
nerally speaking, however, it filters slower than the Swedish 

?aper, though quicker than any other paper tliat I have tried. 
osubly, if of the same weight as the Swedish paper, it would iU- 
Kt as wpidly. When igml«d, it gives 0.42 in 100,00, or less 
tbiHiahBlf per cent, of whes. This is less than the ashes of the 
Swedish paper, which in a comparative experiment gave 0.fi79 
per cent. 

This is, therefore, the best paper that I have yet examined, 
except the Swedlsli, and as it con be sold in Glasgow at less than 
afourth-partof the price of the Swedish paper, namely at Is. 9d. 

r!r quire of demy, wliile the Swedish is 6s. 6d. per quire of pott, 
have chosm this p^er, as the material for the commercial cir- 
cular filters. Consequently, the following circular filters are 
now made in Glasgow of this filtering paper, for sale, in packets 
of 100, at the fiillowing prices : — 



2 

6 
6 


Diuneteroftbe 
Funnel. 


rnccoflhe 

Funnel. 


DitB»teri>fthe 

F[ller. 


Pooe of lUO 

Filten. 


21 


6d 
6d 
61 
6il 
»d 
It 


5 incfau 

aj — 
3i — 

4 

6 

7 


8d 
4d 
6d 

1.1 
ed 
to.1 



XDCLCOBATION. '9 

AflHES OF FiLTBM. — The a^es giren by one of these filters is 
equal to the 23Bth part of ite weight, or equal to the vmght 
of the fitter nrultipUed by 0.0042. In BnalyBie, therefore, 
vou dry and wdgh the filter before use (p. 68) and when it is 
uimt with a precipitflte you deduct from the weight of the ig- 
nited precipitate one-239th of the weight of the filter as the 
weight of tne ashes of the filter. Thus, when a filter weighs 
IB,04 grains, you deduct from the joint weight of the precipitate 
and the ashes of the filter 0.08 grain, (19.04 multiplied by 0.0042) 
as the weight of the ashes of the filter. 



WASHING OF PRECIPITATES. 

EDULCORATION. 

Atter haring precipitated a snbatance, it is generally necessary 
to effect a complete separation of the precipitate from the solu- 
tion. You must allow the precipitate to subside. It sometimes 
fidls down very slowly; sometimes very quickly; in general, 

the subeiding is iacUitated by gently wanning the solution. The 
Beaker glasses (page 62), answer excellently lor tliis purpose. In 
the case where alnioina or peroiide of iron lias been precipitated 
by an esceaa of ammonia, and where a salt of lime is present in 
the dilution, the presence of atmospheric air must be cat off as 
completely as possible. This is effected by using a precipitating 
jar, of which the mouth has been ground smooth on a stone, so 
that it can be closed air tight by the application of a fiat plate . 
of ground plate glass, rubbed with a little tallow. The nm of 
the tunnel in which the sabeequent filtration is to be effected, 
should also be ground flat like the mouth of the jar. While a 
precipitate is subsiding, you prepare a filtering apparatus, like 
that depicted at page 66; and when the supernatant solution is 
clear, you decant it into the filter, taking the precaution of not 
disturbing the predpifate- When the clear liquor has nearly 
all passed through the filter, you stir up the residue with the 
precipitate, and bring the whole upon the filter, washing out 
the vessel with a little distilled water, and pouring the washings 
over the precipitate. When the precipitate adheres to the glass, 
so that it cannot be removed bv the glass rod, you must rub it 
off with the point of a clean feather, or with the end of your 
forefinger, which must previously be washed verj' clean, and 
the precipitate on which must be carefully washed off by means 
of the washing bottle, or edulcorator, an instrument contnved by 
Bbriklics, and of which I shall speak presently. 

When the liquor has all run through the filter, and left the 
precipitate in a comparatively dry state, it is still necessary to 
n«e ue latter foua the portion of the solution with which, be- 



80 XDULCORATIOK. 

ing a very spon^ mass, it must necesearily remuo impreniated. 

You effect this by washing it with distilled water, by (fie help 

of the edulcorator, or washing bottle. 

The edulcorator is a bottle the mooth of which is closed by a 
cork, through which ashortpieceofstrongglass 
tube is passed; butsoBsnotto project far beyond 
the cerk. The size said shape of this coi^ and 
tnbe are figured in the margin. Another and 
an improved form of the tube ia represented 
below. The price of such a tube is 2d. The 




price of a washing bottle complete, rariee ac- 
cording to its capacity. A 3 oz. bottle costs la 
— I oz. Is. 3d.-^ oz. Is. <>d. These ore the 
Gla^ow inices of articles of German manu- 
factwre. The cork must fit the bottle very 
tight, and the external orifice of the glass tube 
must be very small, never exceeding the ^ of 
an inch in diameter. It is handy to have two 
such flasks, one with a wider tube than the other, to give a 
larger stream of water when required. The orifice of such a 
tube can be widened by grinding it upon a sandstone, or rubbing 
it with a file which has been anointed with camphorised tur- 
pentine, or it can be narrowed by holding it in the ilame of 
the spirit lamp, or before the blowpipe. The bottle should be 
rather mare than half &1I of distuled water. If you hold the 
edulcorator vrith the cork down- 
words, and then put the point of 
the tube info your mouth, and 
• blow air into the bottle, the water, 
upon yomr removing the point from 
your mouth, will, for a few mo- 
ments, be expelled from the edul- 
corator with considerable force. It 
passes out in a fine stream, which 
can be directed upon the precipi- 
tate in the filter so as to stu it up 
and wash it with great ease and 
effect. Tovrards the end of the 
edulcoration, the jet of water 
should be directed towards the edges of the filter, and not upon 
the precipitate itself, by which means the precipitate is waatied 
down to the bottom of the filter, and brought into a small com- 
pass. Precipitates of a gelatinous consistence require much 
washing. Tne jet' of water is sometimes destitute of sufBdent 
force to stir them up. in this case you may stir them with a 

.oogic 




ei 

small rfasa rod with a round end; but you must be exceedingly 
careful not U) force the rod through the filter, otherwise the 
filtration will have to be repeated. It is to be observed thd^t 
after every addition of water, no more is to he added till the 
first cpiantily is completely run through, otherwise you do not 
effect a washing of the jirecipitate, but only a continued dilution 
of the solution among it. 

A prejudice appears to exist among British chembts, against 
the use of this most convenient little apparatus — aridng, 1 be- 
lieve, from a rash statement made b^ Mr Children, who af- 
firmed that the water issuing from it must "squirt in the 
operator's face." A Tery clumsy operator must ne he, who 
allows it to squirt in his face. 1 have no doubt, however, that 
the bottle "squirted" in Mr Children's face, or ho would not 
have thought of putting the grievance into his boofe. 

It often happens that precipitates require to be washed with 
hot water, in which case the edulcorator is particularly useful. 
A A flask, with a tiiin bottom, such as a Florence 

flask, or a gas bottle, is provided with a tube and 
cork, and is fastened to a wooden handle by the 
help of a steel wire. The figure distinctly bIiows 
how this can be managed. Hot water is poured 
I into the flask, and is kept hot over a small oil 
1 lamp, used with the trellis and cylinder (page 
I 24). In using this water, it is uimeceBsary to 
1 blow into the flask, since the steam produced by 
the hot water forces out the jet with suflident 
rapidity, especially if the flask be gently shaken. 
Too violent a current is not desirable, as a ten- 
dency to flashing is apt to cause a loss of the substance under 
operation. A similar vessel can be used when a precipitate is 
to be washed with a saline solution. 

The edulooration must be continued until the precipitate is 
completely freed frwrn the solution in which it was produced. 
This is the case when the liquid which drops from the neck of 
the funnel consists of pure water alone. To find when this is 
the case, yon take a drop of hqoid from the neck of the fuimel 
upon a bright piece of platinum foU, and evaporate the hquid to 
dryness over the ^irit lamp. If it leaves no residue, it is pure 
water; if it leaves a stain, it still contains fixed matters, ana the 
edulcoration must be continued. If a polished piece of platinum 
t hand, a mmilar trial can be made on a slip of clean 



through the filter contains sulphuric acid, muriatic acid, barytes, 
silver, or any other substance for which you possess a re-agent 
that acts as a very delicate precipitant, you may collect a drop 
or two of the liquid at the neck of the funnel, and test it with 
the appropriate re-agent. In this case yon continue the edul- 
coration until the washings give no precipitate with the re-agcnt. 




s 



It is scarcely neceaaarv to inibnn you that the neck of the 
funnel must never be allowed to dip into the filtered solution, 
for the liquor which runa from it can then never be collected 
for testing. 

Wlien the solution has passed the filter, and before the cdul' 
ooration of the precipitate commences, you change the cylinder 
which collects tne filtering liquid, so that the wash water is col- 
lected apart from the orkiuial concentrated solution. In a qua- 
litative analysis, the warn water is generally of reiy little value 
and may be thrown away — being frequently too dilute for test- 
ing, and generall v contaming too little solid matter to render it 
worth the trouble of concentration by evt^ration, excepting 
always the cases where you are working upon scarce or valuable 
substances. But in a quantitative analysis, the wash water is of 
great importance, and must be carefully concentrated by evapo- 
ration, and then be added to the original solution. 

Some precipitates can be washed by the following method, 
more readily than by filtration. It is a process, however, which 
is only adopted when no great accuracy is required, when the 
"recipitate is alone valuable, and the solution of no consequence. 
'he solution and precipitate are allowed to settle in a deep jar. 
The clear liquor is then decanted. The jar ig filled with water, 
wJiich is stirred up with the precipitate. It is again allowed to 
settle, again decanted, and so on repeatedly, till the solid matter 
is sufficiently washed. 

The washing of precipitates takes up so much time, that it is 
advisable, in aU possible cases, to adopt means either for shorten- 
ing the operation, or for carrying it on without one's continued 
personal attention. The following method is often of utility in 
tliis respect. Its principle is that of 
''""'^*^ making a column of pure water continu- 

ally pass through the powder that is to 
be washed. The level of the water in the 
funnel is made to remain continually the 
same, by a contrivance which supplies 
fresh water from above as rapidly as the 
diluted solution passes out tnrough the 
neck of the funnel below, A flask is 
filled with water, and is closed by a 
cork, having a glass tube of a pectiliar 
shape shown in the margin e, passed 
through it. Thlq tube must have ex- 
actly the form and size of the figure, 
with li inch added to the tube e. 
When the flask is turned upside down, 
-- the water runs out only till the air 
within it is expanded to a certaui degree, 
\ ( /^ the capillarity of the Ijube a hindering the 
\^~y passage of any water thence into the air. 
But if the tubea is plunged into a liquid, 



ESCLCOHAITOir. 83 

its cBpillai7 power ceasea, and the waier from the flask then 
flows through the tube a, into the liquid into which the tube 
W8H plunged. Very soon, however, the air in the flask becomea 
BO much expanded, that the pleasure of the atmosphere at dy 
forces down the water in that tube, and finallv a bubble of air 
passes from the tube d, through the neck 6, ana ascends into ibe 
flask. This forces down a corresponding quantity of water, and 
every successive bubble of aii that passes in by the same passu^ 
has the same effect. All this water, of course, flows, out at toe 
point a, and if that point is dipped into a liquid contained in a 
funnel, the level of the water in the latter 
is kept at the same point, as for example 
at the lino e. ' It is the size of the open- 
ing b, as compared with the depth to 
which a is plunged in the liquid, which 
3 regulates the level of the water in the 
funnel. The annexed figure exhibits 
this apparatus complete, a ii the water- 
flask containing the water, and having 
^ the pipe aicdin its mouth. Below it,ia 
seen the funnel, and at the bottom, the 
Beaker glass, b, for the reception of the 
filtered solution. The wooden part of 
tlus apparatus, of Qerman manumcture, 
and Is^ size, costs in Glasgow 7s. 6d. 
The tube fitted into the bottle a, costa 
y Is. 3d. It is however nnnccessaiy that 
ie frame should support all the vessels. 
The bottle a may lie supported by Sef- 
Btroem's bolder (page 39) which is required for other espeii- 
ments, and the funnel by the usual fonnel holder (page 66.) 

If it be necesaaiy to use hot water with this apparatus, the 
hot water is put into the flask, and the latter is covered with 
a wooden cap well stuffed with cotton wool, to hinder the escape 
of heat by radiation. 

The annexed figure shows another method of washing preci- 
"' ' ■ ' ilf-Bupplying stream of pure water. The 

apparatus consists of a flask three- 
fourths full of distilled water, closed 
air tight by a cork through which 
two tubes pass. One of these ef, is 
straight, open at both ends, and 
having the lower end cut off aslant, 
to let air pass out more easily. The 
other tube, abed, also open at both 
-^ ends, is a ^hon with straght legs 
■y of the some length. The outer leg 
/ of this ^phon is dipped into the 
Lquid of the funnel tnat contains 
the substance intended to be washed. 
It is apparant from the construction 




tates 

J 


bym 


eons of a s< 

1 

















84 ITAPORATIOIT. 

of thia apparatus, that the tube abed, mnet act like a sypbMi 
with QoeqnBl le^^B, the working difference of ttie legs baing eqoal 
to the space from y* to a ; bo that if the waterinthefuiuielahaiUd 
not escape bo r^idly from the neck below, as it ia replaced by 
the tube above, yet it cannot rise in the fiumel higho' than the 
level of the line /, since at that point the syphon becomes men- 
legved, and tb^ carriw otoc no water till the level again 
nnks in the funnel. 

Solution or Pkbcipitatks. — It iafveqnendy neoessuy to re- 
dissolve the solid compounds produced by precipitation, in order 
to snbject them to the action of additioDal testa. The precipi- 
t«tee are gently dried on the fiher till they acquire the consis* 
tency of soft dough, a»d are then remoTed from the paper, and 
put into the lic[uid in which it is intended to dissolve them. But 
when the precipitate is very small in bulk, or sticks very closely 
to the filter, or is much ^read over the sur&ce of the pwer, it is 
often advisable not to attempt to separate it from the filter, but 
to expose it, paper and all, to the action of the solvent. It very 
seldom happeru that the constituents of the paper can do any 
mischief. When the liquid has dieaolved the precipitate, you 
filter the solution through a new filter, and thus separate the 
original filter from the solution produced by the precipitate. 
Another method of separatina; a precipitate from a filter is as 
fbUoWB : — Yon take the Amnelwhich contains the iilter and pre- 
cipitate, still in a moist state, and fix it over the vessel which 
is to contain the solution produced by dissolving the precipitate. 
You then take tbeliquid which is to be employed as the solvent, 
and after making it boiling hot, if necessary, you pour it over 
the precipitate in the funnel. In passing through the filter it 
dissolves the precipitate, and separates it frwn the pi^er vnt 
neatly. In this manner peroxide of inm, which has oem preci- 
pitated by ammonia, may be dissolved by hot muriatic acid. 



EVAPORATION. 

When a liquid is exposed to heat, it is converted into vapour or 
gas, which, if the vessel containing the liquid be open, flies aw(^. 
The liquid thus heated is said to evaporate, and tne operation of 
heating the liquid is called evttporalion. If the liquid which 
is evaporated, holds in si^ution a substance of a fixed nature, 
this substance, after the evaporation of the liquid, remains behind 
in a solid state. The operation of evaporation is often employed 
by chemists on this very account. If you possess a mixture of 
BUt and sand, and wish to obtain the salt in a separate state, 
you lixiviate the mass, filter the liquid contwning the salt from 



tbauuouibls sand, and BiterwardB expose it to evapoTKtion. Yob 
tbna obtain a product of clean dry salt, totally free £n)iit sand. 

Vmsels por Ev&pobatioh. — The vesBeb in which ev^ontfon 
is perfonned ought not only to be able to reatat heat, but ako the 
GOROBlTe action of acida and olcalka, which often act in a very 
powerful manner, when present in conc«nti»ted solutions. They 
ought, moreover, to be of such a form as to expose a large sur- 
face of liquor to the atmosphere. Capsules of porcelain, or 
of silver or platinum (page 13) are most g«nerallv employed. 
The p<Mt:elain made at Berlin is much superior to that made by 
Wedgewood, both as respects its power of bearing sudden changes 
of temperature, and of withstanding the 



ical finida. Silver ie properly adapted fcr the evaporation of 
alcaline liquors, and platinum for the evaporation of acid liquors. 
Watch glasses, broken pieces of Florence 'flasks, and crucibles of 
porcdain and platinum, can be nsed for the same operation, and 
even flat plated of glass are useful when single drops of a solu- 
tion are to be evaporated. The vessels used for evaporation 
shonld always be thin at the bottom, in order that they may 
bear, without breaking, the sudden application of heat. 

The porcelwn evaporating basins made at Berlin, are of four 
different forms, and of many different sizes, as I shall mention. 
All these varieties are now imported 
L into this country, and are sold in Olas- 
J gow at the prices named below. The 
' firat of these varieties in fcrm is figured 
in the margin. It Is a round basin 
_ about three times as wide as it b deep, 

1 furnished with a spont. The sizes and prices are as fol- 
lows : — 



Nm. 




Nm. 


DUrattcn. 


Piictf. 


00 


Hi inchH. fd 


6 


6 ioches. 


3> 4d 




Si M 




1i 


3i Od 




^ lOd 


a 


Bi 


4)0d 


2 


3J la Od 


9 


10 


6< Od 


a 


4 It 3d 


10 




9«(!d 




41 !■ 6d 


II 


13 


lOied 



The second variety of th^e basins consists of a semi-globular 
basin without spout. The dzes of this form are as follows — 

No. 000— 1 JDcli diameter. 3d 

t—Sl — a Od 

2— 6j— Si 6d 

The third variety is a basin about three times as wide as it is 
deep, without spont, but with the entire edge turned outwards m 
the manner of the soluUon jar figured Of page 62, so that it is 
easy topouialiquidfromanypartoftbeedge. The entire sut&c« 



86 KVAPOBATJON. 

of these barins is glazed, except a small central part of the oi 



1— 3J — lod 

S~i _ la od 

3—11 — ■ 1« BJ 



The four eizes from 00 t« 2 are all admted to fit the per&irated 
plate of the lamp furnace, p^e 25, §. 111. They are aold in a 
nest for 3s. 

The fourth variety of Berlin basins is nearl v of the aemi-glo- 
^ bular ibnn, hut it is provided, not only with 

, i ^""^"^ * spout, but also with a handle, all in oim 

^-^^^V"—^ piete of porcelain. The form is exhilMtcd 
^ ' in the margin. The sizes are as followsi— * 

No- 1—2 inchra diametFr lOd 

2— ai Is Od 

3—^4 il 3d 

A few additional vessels of Berlin porcelain, will be described 
in a subsequent section. The Teasels are now on the way from 
Germany, out I have not yet seen samples of then). 

There is a cheaper material than the Berlin porcelain used in 
Qermany, in the construction of evaporating basins. It is called 
in that countn' Sanitaetggut, Though inferior to Berlin porce- 
lain, it is stjll superior to many varieties of earthenware eva- 
porating ba^ns made in England. A quantity of tbo Sanitaet^ 
gut has been imported into Glasgow, where nests of six basins, 
from 2j inches to 6 inches in diameter, are sold for 2s. 6d, 

It is not easy to supply information respecting the prices of 
vessels of platinum, as they vary greatly. The following, how- 
ever, are the prices of several smul articles of that metal on sale 
in Glasgow in the summer of 1837.— 1. Hemispherical cup, A 
inch dituneter, with handle, 2a. This also serves the purpose <a 
what is sometimes called a blowpipe spoon. 2. A cup of the 
same kind | inch diameter, Ss. 3. Capsule of the size exhibited 
at page 14, with both spout anil handle, 10s. 6d. 4. The same 
article, 1 inch diameter, 7s- 6d. 

PaocEn OF EvAPOBATioN. From this accoout of the veMeli fin- 
evaporation, I proceed to a description of the operation. — The 
solution which is to be evaporated must Arst be tranavased into 
the evaporating basin from any other vessel in which it may 
happen to be contained, with due observance of the precantioDS 
wlw!h I have pointed out in the article on Decantation, page 69. 
The evaporating basin is then to be placed in the sitoation where 
it is to receive the heat necessary for vaporizing the fluid of the 
solution — for example, it is to be placed upon a sand bath over 



BTAPOIUTiON. $7 

the Ikige fhrnaee, (pase 30} sr the lamp furnace, (page 27) or iu 
the po^rated plate of the lamp furnace, (page 27) or upon the 
tcumgle support over a lamp (page 37). 

T1^ reMel in which a solution is er^rareted, should, during 
the operatioii, be eorered; portly to prevent the conttunination 
of the product by dost, and partly to prevent a loaa of matter 
by ebullition or spirting. When the evaporation is slow, and 
no spirting is produced, two slasa rods may be laid acroae the 
^peule, and a double fold of blotting paper be laid upon them. 
. This paper should be chan^d aa oBen aa it becomes so soft, or 
•0 much corroded by acid steams, as to be liable to fall into the 
solution. A different method of protecting the cajwule, consists 
in putting a larger capsule upon it, and filling the upper capiule 
with hot sand, to keep it from ODndennng the iteam which rises 
&om the solution. Small capsules, or a crucible, may be covered 
by the platinum capsule (page 14), placed upon them in such a 
manner as to allow a apace for the escape of the vapour. In all 
cases, the cover must dip downwards, in order that the fluid, 
which is throvm upwards, or condensed upon it, may retnm to 
that below. If the convex side of the cover were uppermost, 
particles of matter existing in drops of the solution could be con- 
veyed to the outside of the vessel and be lost. 

The contents .of a capsule should be frequently stirred dur- 
ing evaporation, by means of a glass rod. Lumps of saline mat- 
ter, tuid hard diy crusts, should be broken down with great care. 

When a solution is to be evaporated to dryness, much caution 
is necessary in conducting the operation at the period when the 
mixture becomes thick. A very gentle heat must then be 
applied, and the mixture of solution and solid matter must he 
stirred continualiy. If this care is not taken, part of the con- 
tents of the vessel are invariably thrown out by the sputtering 
of the pasty mass. All hard lumps which appear must be 
broken down, and the powder be well mixed with the moist 
substance. If the lumps are t«o hard to be broken by a glass 
rod, a small pestle may be employed for that purpose ; care 
being taken, in an analysis, to wash &om the pe^e the matter 
which may adhere to it, and to preserve the solution to add to 
that formed by the subsequent solution of the evaporated mass. 

When lai^e quantities of liquid are to be evaporated at a boil- 
ing temperature, as, for example, when a mineral water Is to be 
concentrated fbr analysiB, the evaporation may be etfeoted in a 
Florence flask, or still better, in tue thin solution jara pictured 
on 'page 62. These can be very properly heated over the lamp 

It sometanes happens in analytical experiments, that a heavy 
powder lies at the bottom of a solution which is to under^ eva- 
poration. When heat is applied to the evaporating vessel m such 
a ease, it often accumulates at the bottom, so as to produce a 
series of explosions, which scatter the solution out of the vessel. 
This accident is best avoided by putting the solution into a cru- 

, .. Cooglc 



EVAPORATION. 

cible, OF any otiier deep vessel, 
fixing it aalmit on a triangle aap- 
port, and placing the lamp in such 
a position beneath, as to make the 
jtwne strike M;ainat the side or the 
Dpper edge of the solution, rather 

than against ita bottom. The evaporation then proceeds quietly 

and rapidly. 

EvAFOiLATioN IN Cldeb Vebseu. — The vcssel containing the 
solution which is to bo evaporated, is placed under the receiver 
of an air pump, in company with another veceel containiiw a 
substance which eagerly attracts moisture, such as strong oil of 
vitriol, fuaed chloride of calcium, or calcined potash. The air is 
sometimes exhausted, and sometimes not. The evaporation pro- 
ceeds with greatest rapidity when the receiver is exhausted. 

Evaporation in the Largb Way. — In general, when a liquor is 
to be boiled, the heat is applied below the vessel containing 
it ; but in chemical manutactoriea, where it is necessary to eva- 
porate very lai^e quantities of liquor at a small expense, it is 
common to employ stone boilers contrived in such a manner 
that the heat may be apphed to the surface of the liquor. These 
boilers are lai^e oblong chambers, with a brick arch built over 
them, a fire place at one end, and a chimney at the other, proper 
openings being also providedfor inserting or examining the sub- 
ject of operation. The fire being lighted, the flame plays along 
the surface of the liquor, which by this means is evaporated^ 
Boilers or furnaces of this kind are sometimes made of sufficient 
capacity to contain ten thousand gallons. 



i,Goo;jli: 



KTAPORATION. S9 

i Wi^TEH Bath. — A Teaael heated in boiling water, or in the 
ahma aridngfrom boiliog water, never becomes heated above the 
boiUng point of water. Hence, a water balh, e, vessel so contrived 
aa to bold wftter, always boiling, and to afford means of apply- 
ing its heat to odier bodies, is Sand to be of great use in cnem- 
kiS laboratories, in cases where a moderate and regular degree 
of heat is required t« be long sustained. In the drying of pre- 
cipitates ; in evaporating for crystallisation, such solutions as 
si^er decomposition when heated above a certain moderate 
temperature, such as the red prussiate of potash. ; in the prepar- 
ation of vegetable extracts ; and in experiment with organic 
sabatancee of varions kinds, the water bath becomes very service- 
able. A familiar eiainple of the uae of the wat«r bath is pre- . 
sented in the conunon carpenters' gloe pot. The most conve- 
nient water bath for a l^ge laboratory consists in a copper 
boiler, built into a furnace, and covered with a flat top p^mr- 
ated with holes of different size. Flat plates of copper are pro- 
vided to close these holes when necessary, and cnidbles, 
flaedce, and capsules, are inserted into them to be heated. A 
doubled bit of paper is put between the flask and the edge of 
the hole on one ade, to prevent the crashing of the vessel in the 
event of contraction of the metal by coolij^, taking place acci- 
dentally 

I For use in the small way, 

' ' ' ' — '' — ' ■ *■ ■' — ' the most convenient tvater bath 

yet contrived, is an apparatus 
composed of two pieces of Ber- 
lin porcelain, thelorm of which 
is exhibited in the section 
drawn in the mai^. Three 
sizes of this apparatus are now 
to be had in ulaagow: — 
No. 00— «1 inebe* diunelcr Sa 

0—5 4* 

J-Bj 61 6d 

The water to constitute the bath is boiled in the under vessel, 
which is supported for that purpose over A gas light or spirit 
lamp, by means of the lamp cylinder, page 24. The substance 
to be evaporated or dried is put into the upper vessel. The whole 
apparatus is glazed, and of the same nature as the Berlin porce- 
lain capsules. 

The annexed figure lepresents a miniature 
water bath. The wide glass tube contalna.water 
supposed to be boiling over a lamp. The long 
narrow tube contains die substance under experi- 
ment, which in this position is subjected to the 
heat of boiling water as long as the heat and the 
supply of water is kept up. 

b3 

i.,< ,■,,-< 1 1, Google 




90 

DftTiNO OF Pbfclpitates. — AtteT filtration and edulcoration, it 
is often □eceaaarj' to dry the precipitate which remains on the 
filter. The latter is carefully drawn out of the funnel, and 
placed upon Beveral folds of blotting paper, and the whole is then 
1^ in the upper capsule of the water bath. In common experi- 
ments, the filter and ita conteDts can be rapidly dried by bein^ 
placed upon a warm brick, which readily abeorbs the moisture. 
In careM experiments, the use of the water bath cannot be re- 
- placed by that of the sand bath, because the sand often becomes 
too hot without it being perceived, and is liable to do mischief. 

DftYiNO OP Glass Vessels. — While speaking of different me- 
thods of driving away water by evaporation, I may notice the 
way in which moisture can be expelled from flasks, retorts, long 
glass tubes, and the like. To do this, you worm the vessel that 
is to be dried. You insert a long glass tube till the end nearly 
reaches the bottom of the vessel. You then blow air with your 
mouth into the other end of the inserted tube. The heat 
vaporiEes the water, and the current of air thus produced, 
immediately carries off the vapour. It is still better to suck the 
air throngh the tube than to blow it through. 

Sait Bath, — A saturated solution of common salt boils at 228" 
Fahrenheit. This temperature can, therefore, be conveniently 
applied, on the same principle 
as the heat of boiling water is 
applied, to the heating or eva- 
porating of liquids which cannot 
be placed over the naked fire 
without danger of burning, ex- 
ploding, or boiling over, or of 
' occasioning the destruction of 
the vessel in whiuh the opera- 



bles the porcelain water bath, 
described above. It consists of a copper kettle for containing 
the solution of salt, which is supported oyer a charcoal fire, and 
provided with an upper vessel to hold the solution that is to be 
evaporated. When the solution of salt a is at a particular state 
of concentration, it gives all the heat it receives from the iirc to 
the vessel placed within it e, where the evaporation then pro- 
ceeds. The kettle a is provided with a stop cock e, which per- 
mita the solution of salt to be brought into occasional cc"""*''"" 
with the atmosphere. 



»-i h, Google 



CRTBTALLISATIOK . 



CRYSTALLISATION. 

Whbh fluid anbetanees are saflfered to paae with sdequaU slow- 
neas'to the solid state, the attractive forces frequenuy arrange 
the ultimate partielea of the substancee in such a nwaner as to 
fbrm regular geometrical Bolids, to which has been givell the 
lume of erytlcU. 

Perfect mobilitj among the corpngclce is CMential to crystal- 
liaation. The chemist produeea it either by igneoue iiision, by 
vapotiaation, or by solution in a liquid. When the temperature la 
slowly lowered in the two fonner caaes, or the liquid slowly ex- 
tracted by evaporation in the last, the attractive forces resume 
the ascendency, and arrange the particles in synmietrical forms. 
The fonnatiou of crystals bv solution is effocted in vessels such 
as have been descTii>ed in the articles on "Solution" and "Eva- 
poratioii,' particularly in the porcelain evaporating basins, de- 
scribed at page 8G. Bodies that crystallise &tnn watery solutions, 
frequently retain a small portion of water, which remains coo- 
fined in the crystals in a state of solidity, and does not reappear 
till the crystalline nature of those bodies is destroved. This 
. water is cfdied water of erytlallieation. The mode of obtaining 

Sitals of certain bodies, differs according to their particular 
itades. If it be desired to obtain crystals of a salt that is more 
soluble in hot water than in cold, all that there is to do, is to put 
into hot water as much of that salt as it will diffiolve, to make, in 
short, a hot saturated solution, and then to allow it to cool gradu- 
ally, the slower the better. As the heat which contributed to the 
fluidity of the salt iilcs off, crystals wiU be deposited at tile bot- 
tom of the vessel. Bolts that are soluble in equal parts of hot 
and cold water, can only be crystallised by driving off the water 
of aolntion in vapour. But this must be done veiy alofvly; for 
rapid evaporation leaves a salt, not in a crystallised stale, but in 
that of a solid irr^ular mass. By the operation of crystallisation, 
salts which differ In their degree of solubility, or whose solution 



1 the 

same liquid, and one of them be much more soluble in h at than 
in cold water, and the other be equally soluble at any tempera- 
tnre, then, ou evaporating the solution sufficiently, the latter 
salt will crystallise while the liquor is hot, whereas the other 
will not shoot into crystals until the liquor is cold; thus, by 
alternate evaporation and cooling, the two salts may be obtained 
nncombined, though perhaps with a little intermixture of each 
other. 

The only general mle that can be giv<ni, for the purpose of 
directing you how to crystallise bodies, is this: Slowly evaporate 
the solntion, until a pellicle, or thin skin, is formed on the sur- 
&ce of it; than set it in a cool place, where it vrill be free from 



93 CRTSTALLiaATION. 

dost, and can rem^ undiaturbed. This rule will not, by aiiv 
means, apply to all aalts, nor is tbeie any other rule that will. 
Nothing but experience, and a knowledge of the habitudes of 
the various crystalliHable substanMS, can be of much svul. 
- Many saline solutions, when set by to cryHtallise, throw onf 
ntmiiicationH of dry salt, which creep over the edge of the basin, 
•nd, if not interrupted, extend over the entire outer sur&ce of 
the basin, and along the contiguous table. This is prevented by 
rubbing a little tallow round the edge of the bamn, or by nrin g 
a porcelain cspeule with a burnished gold edge. When a hot 
HOlution is to be cooled slowly, the vessel should be placed on a 
enshion, and covered with a few folds of cloth. When a cold 
solution is to be exposed to spontaneous evaporation, a prooess 
which produces large and regular crystala, the vessel should be 
placed in a dry situation, and be left uncovered, or only be 
covered with a piece of paper to keep out the dust. When crys- 
tallisations are performed on the small scale, flat plates of glaas, 
watch glasaea, and the platinum capsule (page 13), are uaefnl; 
but in general, deeper vessels are preferable. A solution set by 
to crystallise, should be contained in a vessel so shaped that the 
liquid may be about twice as wide ss it is deep. Consequently, 
very shallow or very narrow vessels are not so well adapted for 
this operation as those are which have the form of basins. Rough 
snifaces and porous substances promote crystallisation. 

Crystallisation is a process very frequently resorted to by the 
chenust, in some cases for the purpose of producing bodies of 
regular form, from which to infer the nature of an unknown 
substance submitted to experiment, but more frequently as a 
means of separating a crystallisable compound frvm various im- 
purities not susceptible of crystallisation. In nearly all cases 
where a chemical substance is required in a state of purity, to 
be used, for example, as a re-agent, or to be employed in quui- 
tilative analysis, or in the preparation of substances for such usee, 
it is almost the general plan of the chemist to begin the prepara- 
tiiHt of that pure eubetance with a salt, previously purified by 
several succ«flsive crystallisations, from solutions eficcted in dis- 
tilled water. Thus, pure potash and soda are prepared from pure 
ciystalsof the carbonate or nitrate of those alcalies, pare barytes 
from ciystals of the nitrate of harytes, pure muriatic add from 
purified crystals of chloride of sodium, pure nitric acid from 
pnrified ctyatals of nitrate of potash, and so on. 

Solutions prepared in other liquids than water, oflen yield 

S'stals that contain other compounds than those submitted M 
ution — crystals in which a certain quantity of the solvent as- 
sumes the solid state, precisely in the same manner as water doe« 
in Budi crystals as are said to contain water of crystallisatjon. 
Thus, sulphate of potash, dissolved in oil of vitriol, produces crys- 
tals which in a dry state consist of sulphate of potash, and oil of 
vitriol. Many salts, dissolved in ilcohol, produce, as Professor 



CETSTALLISATION. 93 

GuEiH has diown, dry crystals, wbich contain a certain pro- 
portion of alcohol. 

Wlien a aolution is slowly evaporated, the ciystals obtained 
are large and frequently grouped together, bo aa to form hollowa 
of a considerable aize. These hollows retain a portion of the 
mother liquor, which consequeutly contaminates the crystals. 
To prevent this retention of motner liquor by a crystallising 
Halt, it is only necessa^ to stir the solution whue it cryataUisGS, 
and thus prevent the formation of large crystals- This method 
is practised in the manufacture of r^ned sugar, saltpetre, and 
variouie other substances. 

When crystallisation ia to be effected on the small scale, for 
the purpose of determining the form assumed by a salt on ciys- 
tallisation, flat platea of window glasa anawer the pun>oee toler- 
ably well. A slip such aa that described at page 14, a held flat 
by one end; a drop of the solution, an inch brMid, is placed near 
the other end, and ia warmed over a lamp. When tne edges of 
the drop begin to look white and dry, you remove the flame and 
let the drop cool; whereupon crystals soon appear, affording by 
their forma, though generally incomplete, indicationa of the 
nature of the aalt submitted to examination. For example, 
dropa of solutions of nitre and common salt, of alum and sulphate 
of soda, tried in this way, afford results not easily confounded 
with one another, by one accustomed to observe crystals. 

The formation of crystals by fusion occurs with such sub- 
stances as sulphur, leai£ and bismuth. It seldom succeeds ex- 
cept when tried with large quantities of the snbatancea. See 
" Sulphur." 

The operation of crystallising by vaporisation, will be explained 
in the article on " Sublimaticai.'' 



EXERCISES AND CLASS EXPERIMENTS. 

1. Dissolve a quantity of ealtpetre in water with the aid of bent. 
Setthesolationandein adeepbuin to cr^atallise. Pick oot the 
beat cryrtald, and preserve them as mecimens. Evaporate the 
liquor Sigaiu, to fuiiish a necond crop of crystals. 

S, In the bauie manner, prepare and crystallise solntions of ml- 
phate of iron, salphateof copper, sulphate of soda, HOlphate of meg- 

3. Diasolve equal weights of saltpetre and carbonate of potash in 
a small quantity of hot water, and allow the solution to cool in a 
capirale. The ureater part of the saltpetre will separate in crystals, 
but the whole of the carbonate of potash will remain in solution )u 
the residnal liquid, or mother water. 

4. To HIKE CiMBERB, OR LITTLE WlCBER-FiaUllFS, IFPEIR AS IT 

TRET WIRE Crtstillised.— Saturate water kept boiling, vith^ara; 
then set the solution in a cool place, snspendiUB in it, by a balr, or 
floe silk thi«ad, a cinder, a spng of a plant, or any other bine ; an 
the solution cooU, a beautifiil crystBllLsation of the salt takesplacc 
upon the cinder, &c. which are made to resemble specimens of min- 
eralogical spars. 



.. .OOQh 



94 CHTSTAUJUTIOIf. 

S. 7% malte Cttaiatd Crftialt <tf .4Ai».— MetUod at proceeding.— 

Hot Hatnrated solations of atam are mixed with TUlooa colonnng 
■abstances, and are then gobmitted to crjstallisation. Colunra to be 
lued: — The additian of powdered tormeric prodncea traaaparent 
villoiB crystala. Powdered Utmua prodaceB traasparent red cryDtaU. 
Logwooa makeg them purple, and common writine ink black. Tli« 
more troubled the solution looks, the finer are the crjstala itafibrdii, 
BO that filtration la not neceasarj. These coloured crystals are more 
easilj destroyed than those of pnre alom. The bestwBj topref^rie 
them IB to support them ander a bell glass, which rests in a capsule 
that contains a Lttle water. This arraii|Femetit produce* a mout 
atmosphere, which i« not only useful in this case, but also for the 
preservatioQ of crystals of sulphate of copper, and varionn otbe/ 
Halts whose colours are dependant upon then water of crystaUisa-. 

The crystallisation of ainm is promoted by hanging in its aolntiOTi 
mbitances With rough Bnrfaces, such as cok«, eottou, porooa wood, 
and pnmice stone. 



ing, which may be known by lettinit a drop of it fall on a plate of 
Blass. When it is in this state, set it by ; and when it is cold, pour 
into a flat bottomed vessel the liqnid part of the solution on the 
mass of crystals which will be formed at the bottom of it. After a 
few days solitary crystals will be formed, which will gradnalty in- 
crease m size. Pick oat the most regnlar of these, and put them 
into another flat-bottomed vessel ; and poor over them alreBh solu- 
tion of the salt evaporated till it crystallises on cooling. After this, 
alter the position of every crystal once a day with a jjlass rod, so 
that bU the faces of it may be alternately exposed to the liquid ; for 
the face on which the crystal rests never receives any increment. 
By this process the crystals gradually increase in size. When Uiey 
are so iBxge that their forms can be easily distinguished, take th« 
best of them, and put each into a vessel separately; add a fresh so- 
Intion of the salt as before directed, and turn every crystal several 
times a-day. Bvtbis treatment yoamayobtain them almostof any 
size yon wish. It is necessary to pour on the liqnid from the crjs- 
tals, and add fresh liqnid in its place, very frequently | for the solu- 
tion, alter depositing a certain portion of its salt, becomes weak- 
eued, and then attacks the crystals — rounding ofi" their angles in the 
first place, as an attentive observer may perceive, and Infallibly 
destroying them, unless renewed. — The student may endeavour to 
form thus a regular crystal of alum, to exercise his dexterity. 



Into twooancesof boiling water, put as much aulphate of soda, as it 
will dissolve (about three ounces). Pout as mnch of this satorated 
"Olntion, when boiling hot, into aphial, as will nearly, but notqoite, 
fill it ; cork the phial closely, and let it stand to cool. When cold, 
the BOlntion is still fluid ; but the instant you draw the corif, a very 
beantitiil, hut confused crystallisation, of the whole mass, imme- 
diately takes place ; and, at the same time, so mnch heat is evolved 
aa to make the phial warm. 

The explanation qf the experimeTii ii this : — Water dissolves more 
sulphate of soda when hot than when cold ; and cold water dissolves 
more in proportion as the pressure of the BJtmosphere is diminished. 
The hot water is here saturated, and, if it had beeniuSered to cool 
iu an open vessel, would have deposited part of the salt< Bat, in 



lOHrriON. 95 

AIs due, none' is deponted, for b^ mflWing the Holntioii to cool 
m H. close vessel, a paVtial vocoiuii is prodiiceil at tbe surface of it, 
(tte Btettm which occupied the top part of the phial when the cork 
IB inserted, being', bj the mbseqnent cold, cocdenged.) and the water. 
«rkeo cold, is thus enabled to bold in solatioQ, all the nalt which 
it bad dissolved when hot. Aa soon, however, as, by drawing tbe 
cioTk,yDn admit the nsaBlpTessnreof tbe atmosphere, the cold water 
is rendered incapable of holding so moch salt in solntion, and nart 
is, therefore, iniitantiy crjstallised. The heat which is ei^oli^ea, ii 
the heat of liqnidity of tbe portion of the eolt which thus becomes 
solid. If, when tbe salt has crytBllised, von plnnge the phial con- 
tBinins it into hot wat*T, it will be again dissolved. Yon may then 
cork the phial, an before, and the same solntion will serve for a re- 
petition of the experiment. 

8. Dissolve 4 parts of crystallised snlphate of soda, and 3 part* 
of saltpetre, in 15 parts of warm water. Divide the solution into 
two portions. In one of these portions place a crystal of aaltiietre, 
and in the other a crystal of snlpbate of soda. Cover np the two 
srintionatjiat they me; cool slowly without evaporation. The first 
•olntion Vfill deposit only saltpetre, and the Beonnd only solphate of 
Koda. This phenomena is explained by assamingthat the attraction 
between the particles of saltpetre and saltpetre, is greater than that 
between saltpetre and watf r, or between saltpetre and snlphate of 

- 9. The following is a neat way of promoting the crys- 

> < tullising of salts in smalt Rotations. Pnt a coldsatorated 

Eolntion of a'uy ciystalliaable salt into a deep Jar, aai 
bang in it a tine of silk or horse-bair, fastening a Btjotto 
tbe bottom of the line, and a bit of cork to the top. Set 
the solution aside, and yon will soon perceive crystals to 
form abont ihe shot, and along tbe line. Sugar win 
crystallise or " ■'■•'' — ' 



t 



a threads fixed ai 



IGNITION. 

It is often necessary to make a sabstance red hot, either to A'ee 
it from water, to bum it, melt it, or to decompose and char any 
organic Bubstanceg which it may contain. Sometimes the ienj- 
tioB amy be performed in a Heaaian cmcible, or in a poTcelain 
cracible, or for want of that, in a clean tobacco pipe. But in 
most cases, the vessel in which a Bubstance is e3:poBed to ignition, 
is best when made of platinum ; only, it m necessaiy to remem- 
bw, that platimim rcMels can never be employed when regnline 
met^ such as rmcombined lead or copper are likely to be pro- 
duced by the ignition, or where free chlorine is likely to be dis- 
engaged during the experiment; as, for example, when mnriatio 
acid comes into contact with the peroxides of manganrae or of 
lead. See " Plstiniim.' 



PiutTonm Vmnxs. — The Bimpleat fotm of an iiutmment for 
ignition is a piece of platinum foil, aa thick as stout writing paper, 
and as large as tlia 
figure in the mar- 
gin. Thesabstaooe 
to be ignited ia 

filaced on one end of the foil, which m previously hollowed a 
ittle by the pressure of a finger, and is then exposed to the 
flame of a spirit lamp or the action of the blowpipe. 

liiia foil can be made Intensely hot beibre the blowpipe, be- 
cause the thin metal corriee away very little of the heat applied 
to it. When a substance is to be at once heated and oxi^sed, 
both objects can be effected by directing the blowpipe flame 
upon the bottom of the foil immediately under the substance 
to be heated. Platinum ia so little qualified to conduct heat, 
that a piece of foil of the above size can be held at one end by 
the fingere, while the other is r^sed to a white heat. I refer 
you to the section " on the use of the Blowpipe," for an account 
of the method of managing that instrument. The price of this 
nsefiil piece of apparatus (the platinum foil) is 8d. When it 
becomes ragged at the end from much use, ot is perforated hy 
the accidental fusion of a metal upon it, the part must be cut 
off. When it is worn too short to be conveniently held by the 
fingers, it can still be supported by one of Mordan's holders for 
eteel pens, or by insertion in the end of a small glass tube. 



When a substance is to be heated with fluxee, or when the 
quantity is somewhat considerable, it is convenient to ignite it 
in a little platinum spoon 
like the annexed figure. 
This spoon should Iwstuck 
^ into a tobacco pipe handle, 
Band should be provided 
f with a cover. Tlie latter 
ought to have three pegs 
below to keep it in its pro- 
per place on the spoon, 
and a centre peg on the upper side to serve for a handle. For 
certain experiments, a diver ^loon of this form is convenient; 
but though such a spoon is much cheaper than one fonned of 

Elatinum, it is too fusible and too eauly acted upon by ad^ to 
e generally useful. The chief use, indeed, of a silver spoon, i* 
to assist in decomposing certain minerals, and the salts of the 
metallic acids, by fusion with caustic alcaliea. The cost of a 
platinum spoon of this description is eight or ten shillings. 

Platinum cups of the form and size represented at page 14, oi 
hemispherical cups, half an inch or three-fourths of an inch ia 
diameter, are also very useful vessels for ignition. When they 



97 

are to be exposed to heat they may be held IW the blowpipe 
tongs, or be supported over a tamp on a triangle of very fine 
iron wire. The smaller sort can he placed in a cavity made on 
a piece of charcoal, and heated before the blowpipe, oa will be 
de«ciibed in another section. These cups shoum have on one 
aide a projecting slip, b. quarter of an inch long, to serve as u 
handle. The price of them is 2a. for one of ^ inch in diameter, 
and 5s, for one off inch in diameter, with handle. 

An instrument more generally uae- 
fol than the platinum spoon, but at 
the aanie time more e^ensive, is the 
platinum crucible, which with its 
platinum cover, is represented in the 
margin. The cost of a vessel of this 
size is about £3. But those who wish 
to maVe experiments in qualitative 
analysis only, can have one made 
smaller and slighter for about £1, 
or still raaaller, aoA without cover, at 
hsm three to ten shillings. 

The crucible cover represented in 
the margin, is neuly fiat, and pro- 
vided with three pen to keep it in its place. This is the usual 
French form. In London, the covers are commonly made to 
fit «lose to the bod^ of the crucible by means of a rim, like the 
cover of the porcelain crucible, of which a drawing is given at the 
foot of the next paa;e. 

Platinum crucibles must not be made too thick, because the 
metal ts very heavy, and the crucible, when loaded, becomes in- 
convenient to weigh in a delicate balance. 

The figure on page 19, shows in what manner a platinum 
crodble can be supported over a spirit lamp. The aimexed 
figure shows a contrivance, 
by means of whicii the heat 
produced by a spirit lamp 
can be concentrated and in- 
creased. It is a cone of tin 
Slate 2^ inches deep, 1^ inch 
road at bottom, and Sl inch 
broad at top. Withm it, 
and fixed equidistant tr<ira 
each other, are three plates of iron a, ^ inch wide, and 1 inch 
long, fastened by flanges to the cone, so as to present a support 
for a crucible in the shape of three edges, which separate as they 
proceed upwards. A crucible placed in this cone, as shown in 
the figure, receives the benefit of the flame much more effectu- 
ally than- when it is supported simply by a ring or a trianflc. 
Of course, the bottom of the cone is made to correspond with 
the top of the diimney of the lamp. 
Jai improved BerzdiuB's lamp, which 1 received very recent- 



ly from Berlin, was accompanied by a bioaU iron dome for con- 
centrating the heat about a cracible, when supported over the 
lamp by a triangle, as shown at page 19. The dome was of the 
shape of a sugar loa^ with the upper point cut off, and the broad 
end a little expanded. The height of it was 4 inchj^. The 
width 2^ inches, diminiahing to 1^ inches. It was supported on 
the lamp rod by a braas arm, and could be brought down closely 
to the triangle, so as entirely t* cover the crucTjle, and ptotect 
It from Ekny air but that which came hot &om the flame. 

When placed in aiiimace,the platinum crucible require* to be' 
enclosed m a round Heauan crucible, provided with a foot and 
eover, to prerent its contact with the fiiel. 

In mimy casea, where raetaliic crudblcs are objectionable, ibr 
the reaaona that will be stated under the article " Platinum," it 
is proper to employ crucibles of porcelain, although it is impoa~ 
siblc to heat a substance so powerfully in a porcelain as in a 
platinum crucible, particularly over a lamp. 

PoBCEtiiN CauoiBLEB. — I'or the fusion of chloride of silver, for 
the ignition of a variety of precipitates, and for numerous other 
purpoeea, the small porce- 
lain cupa, described at page 
13, are useful vcBBek. They 
are to he had of two sizes. 
When in use, they may be 
supported by the same means 
as the platinuni cruciblea. 
Covers for them are afforded 

X bj^ the smallest size of porce- 

1 Imn capsule. 

But, independently of these cups, we get from Berlin, porce- 
icibles, with covers, of the form shown in the following 




figure. Two si 




made. The sntaUest 1| inch, the largest 

— 2^ mch in diameter. 

Tnese crucibles are of 
very excellent qua- 
lit^.glazed within and 
without, and so well 
able to suffer transi- 
tions of temperature, 
that the cover may be 
put eold upon the cru- 
cible when red hot, 
without producing 
fracture. The glazing 
witb^ands the action 
of strong acids. The 
covers are not nearly 
BO Uable to split as 

^ aro those of English 

^\ manufiwluie, ma in 



eonseqnence of the oIom texture of the Teasels, they do not differ 
to mnoh nhen weighed in a diy and a damp state, aa do the 
more poMus Bsglian crucibles. The price in Olasg^^w of the 
BD^est cmcible and Cover, aa represented at the bottom of the 
preceding p^e, is 9d., that of the large cmcible is Is. 3d. 

The chief use of these cmcibles is in the ignition of metallic 
oxides, which are easily reducible in connection with metallic 
platinum; in the fosiiHi of metKllio oxides with aulphurets; in 
charring organic matter mixed with redncibte metals, &c. 

When a still larger glazed raudblc is required, the porcelain 
mattraaa represented at pag« 13, may be employed. 

Another Heecription of Berlin porcelain cmcible is represented 
in the following figure. It ia made of nnglnzed porcelain, xad 
is furnished with a cover having a hole m 
the centre, intended to permit the escape 
of the gas g«nemted in some processes. 
There are two sizes, provided with cov<a»>-- 



A larger size, fi by 3i inches, can also be 
had without cover. The price of this is 
1b. 6d. The use of this variety of crucible 
is in fusing such substances as nitrate of 
silver. The crucible is not exposed to a 
free fire, but is placed within a common 
earthen crucible. 
Small glazed porcel^ P*^ useful as crucibles in some inex- 
act operationa, may be had of the capacity of ^ oz., and j oz., 
at the price of 2d, each. They are tw fliick to be generally 

HnssrAH CnnciDLES. — Thefte are a species of clay cmcibles that 
surpass most other substances in their power of resjstmg great 
heat, and the action of the substances used as fluxes. T^y are 
sold in nests at about the following prices: — 

Nest of 3 -3 to 3 iucbeabigb, per neat, 4d. 

S-1to4 do. do, Sd- 

— 0—2 to 6 do. do. lOd. 

They are of a triangular form, without covers, of a dirty brown 
colour, tmd very rough surface. They are of but little use to a 
student of chemistry, who is provided with por- 
) celain and platinum vessels. They are principally 
employed with fumot^s, in the redaction and 
Aision of met^, and in some other operations not 
requiring great nicety, or not admitting of the 
presence of platinum. They require to be both 
heated and cooled very slowly, else they are liable 
to crack. Indeed, the reoscat why clay crudblea, 
which are so very chei^, are not more extensively 
Dsed, is that they break too readily, and are too readily attacked 




100 

by almost everything that u melted in them. The conaequoiee 
of which ia, that they Dever can be used fot a second operation, 
even when thev escape whole from the firat, althongh this is 
nearly impossible, unless the fire in the fiunace be suffered to 
die out, and the crucible and f uniace get gradutdly cool togethtf . 

Oraphite Crucibles, — Blue PoU. — These suffer a very high 
temperature, and are not so ea^y attacked by fluxes, nor so 
readily cracked on cooling, as are the clay crucibles, they are 
liable to communicate both iron and charcoal to the Bubstances 
that are fused in them. They cannot be used in the fusion of 
salt^ which filter through thett mass. They are of but little 
service to the chemical student. The price of one 3 Inches high 
is 3d., 3^ inches high, 7d. 

ToNos.— The best form of tongs for handling the platinum 
crucibles, ia represented in the margin. They dioiud be of 
small size, and kept 
scrupulously clean, so 
as not to communicate 
any hupurities to the 
matter contained in the 
crucibles which they 
are employed to re- 
move. This form of 
tongs is not, however, 
so well adapted for the handling of crucibles that contain liquids, 
.or of earthen crucibles, which are liable when seized by the 
edge to give way under the weight of any heavy charge that 
they may contain, and to leave in the tongs only the portton of 
the edge that they nip. Partly for this reason, and partly in 
order to avoid the chance of communicating extraneous matter 
by touching the inside of the crucible with a branch of the tongs, 
it isjisual to remove earthen crucibles generally, and platinum 
crucibles which contain liquids, by tonga formed in the manner 
shown by the following figure. 




Qeheiul Directions. — 1. If a salt is to be deprived of its 
water cf crystallisation, and the operation is not to be made 
with great exactness, the ignition mav take place in the pla- 
tinum spoon, or in the hemispherical platinum cup, or, for want 



of these, in a small poiceltun cup. ]f greater exactness is required, 
a platinum crucible and cover shouM be need, and the ignition 
be assisted by the conical tin plate. The object of this precau- 
tion is, to expel a small portion of water which is iimnd to adhere 
to some salts with ^rcat obstinacy. If you are desirous of ascer- 
taining the proportion of the water to Uie dry readue, yau first 



101 

vdgfa the CTOcible Mid cover alone, then again with the crystals 
ofsalt within it, and fiaally after the ignitbn. The ignited salt 
should be weighed with the cmcible and cover while still wann, 
bat not until it cas be handled hy the fingem The loss of 
weight occasioned by the ignition ia the weight of the water 
expelled. The difference between the last weighing, and the 
weight of the crticible and cover only, ia the weight of the on- 
hydrous salt. 

2. When a precipitate is to be ignited and weighed, it may be 
burnt with the filter, in a small platinum crucible, provided with 
a cover. The residue is to be weighed, as above; the crucible 
and cover are then to be cleaned, dried, and weighed apart. The 
difference shows the we^t of the precipitate. Aecipitates 
of chloride of silver are ignited and weighed in the amJl por- 
celain cup, page 08. 

3. Sometimes it is necessan to provide the means of bringing 
a ctirrent of air into a crucible when undergoing %nitkm, for 
example, when organic matter is to be charred, converted into 
gas, and expelled. In the position in which a cracible is com- 
monly placed over a lamp, and, as it is represented at page 19, 
it is BUTTOunded on all sides by a current of air, extremely hot, 
indeed, but almost whoilr deprived of oxygen, the force of which 
current rising continually, hinders the access of cold pure air. 
It necessarily follows, from the want of oxygen, that the organic 
matters in the crucible, though charred and intensely heated, 
cannot be converted into gases. To remedy this, you place the 

— crucible upon a triangle, in the 

position shown in the margin, or 
, nx it even a little farther out of 
perpendicular than is here 
shown. You then place a slip of 
tin plate so as to rest partly on the 
iron ring of the retort stand, and partly within the crucible, 
bending the end that enters the crucible a little downwards. 
This metallic slip forms a sort of bridge, which permits atmos- 
pheric air to pass the current of hot gases, and enter into the 
crucible. This you can prove, by chairing a bit of paper ia the 



crucible. As soon as you place the bridge on, vou will observe 
the coal of the paper to bum precisely as a dim c"' "" '"" 
when subjected to the action of^the beUo« 



4, The crucible should, in all cases not otherwise directed, 
he DO larger than is sufficient to hold the mass that is to be ig- 
nited ; for a small cracible can be made hotter than _a lai^ one 
by the same flame. It should also, when no^ otherwise directed, 
always have the cover put on; for substances c&D be made hotter 
in a covered crucible than in an open one. ^ 

5. When a substance decrepitates, or when it is uncertain 
whether it decrepitates oi not, it should invariably be heated in 
a closed crucible, or else be previously pulverized, in order to 
prevent decrepitation. 



102 SVXLIHATIOH. 

Fusion. — The act of convertings a solid iota a fluid by taetam 
of heat. This operation is performed in the game Tceseu, in tlie 
gome manner, and with the aonie precautions, as "Ignition.' 

RiDUcnoH. — The operation by wliich motals are restored to 
their metallic state, ^ter having been deprived of it, by com- 
bination with some non-metolUc substance. The metallic 
oxides, falminaling C^jld, horn silver, cinnabar, and other com- 

Cnda of the same Kind afford examples of reducible bodie*. 
uction is also called revioificatiim. The operation is per- 
formed in crucibles, by the aid of heat, and with the addition 
of certain substances, which act chemically upon the body to be 
reduced. 

Flukes an substances employed to assist the fusion of minerals, 
oi the redaction of metalUc oxides. Crui^jlu.i' is a mixture of 
nitre and tartar, which is put into the cmdble with the mineral 
intended to be fiised. While _fiux is formed by projecting a 
mixture of equal parts of nitre and cream of tartar, by moderate 
portions at a time, into on ignited crucible. It is potash in tol- 
erable purity. Black Jlux differs from white flux in the propor- 
tion of its ingredients. In this, the weight of the cream of twrtar 
is double that of the nitre. The mixture for producing black 
flux may be ignited in the covered spoon, or one of the snail 
porcelain pots or cups, or even in o common tobacco pipe. 

Fusion and Bkdl'ction befobb the Blowpipe. — The reason that 
1 have spoken in so summary a manner here, of the operations 
i)f fusion and reduction, is, that I purpose to describe circum- 
stantially the method of fusing and reducing minute quantities 
of matter, when I come to sp^k of blowpipe apparatus, and of 
analysis by the blowpipe. 

loNniON IN Glass Tubes. — In qualitative analysis, the ^vltion 
nf substances in glass tubes is a process of frequent occurrence; 
but as these ienitions are for the most part performed with the 
intent of prodadDg Sublimation, I shall describe die mode of 
operating under that head. 



SUBLIMATION. 

Sublimation is a process, by which volatfle substances are raised by 
heat, and again condensed in the solid form.'The apparatus which 
it requiree is very simple. Behzelius rerommends the insertion of 
the lower end <rf a )sr%o platinum crucible into tho mouth of a 
smaller one. The substance, npon being heated in the small 
crucible, condenses upon the under side of the large one, wliich 
should be filled with cold wate». A similM' arrangement, with 
cheaper tcsbcIs, is made by inserting a anBll ghued porcelahi 



crucible, (No. 1, p»ge 99) into tbe mouth of the larger glazed 
porcelain mattrasa (page 13.) The Bubstonce to be eublimed is 
placed in the mattrass, and the crucible is filled with cold water, 
wiiich IB changed when it bccomea warm. The sublimate con- 
dense* on the outdde of the crucible, whence it is easj' to be re- 
moved. It is sometimes sufEdent to cover a small capsule with 
a large one, or with a cono of paper; while, in 
other cases, the vaporised body has to be conveyed 
into a flask by means of a conducting tube. An 
alembic is a flask with a wide month, such as is re- 
\ presented in the margin, c, and a capacious hollow 
I stopple, or head, adapted to it. This veesel was for- 
a-ly much employed in distillation and auhlima- 
n. The vaporised matter condenses in the head, 
jt'hence, if liquid, it is permitted to mn off by a Bpont. 

BuBLiMATiON IN Glass Tubes. — lu experiments undertaken to 
prove that a substance will sublime wnen heated in close ves- 
sels, or that, when it sublimes, it produces a particular kind of 
vapour, as respects its colour, or smeD, or that it produces crys- 
tuB ; or in experiments made to ascertain whether a substance 
is volatile or not, or whether or not it can be converted into ' 
a volatile substance ; in these, and many other cases of sublima- 
tion, it is now common to use no other apparatus than a glass 
tube closed at one end, and formed like one or other of the 
figures on tbe next page. 

The substance to be sublimed is placed at the bottom of one 
of those tubes, and is then submitted to heat. The sublimate, 
if any is produced, condenses upon the upper part of the tube, 
and is there examined. 

A vetj particular account of the results obtained by operating' 
with these small vessels, and of the merits of the different shapes 
will be given in the articles "Arsenic," "Analysis by the 
Blowpipe, &e. in succeeding sections. What I have principally 
to do here, is to direct your attention to some general points of 
manipulation relative to sublimation in tubes. 

(oj QualUy of the Tuie».— The class should be thin in sub- 
stance, and free from lead. White glass made with potash is best, 
next to which is pale blueish green glass. Flint glass, containing 
lead, is objectionable for several reasons :— First, it melts at a 
lower temperature than that which several substances require for 
sublimation; secondly, it is readily decomposed by the flame 
employed to heat it, the combustible gases miieh accompany the 
flame absorb oxygen from the glass, and produce a filoi of metal- 
lic lead, which interferes with the observation of the sublimation 
within the tube; lastly, one of the most important of the sub- 
stances which are examined in tubes of this sort, namely, arsenic, 
happens to require so h^h a temperature tor its sublimation, 
that flint glass is almost invariably decomposed durii^ the opera- 
tion. The consequence of which is, that the operator is uncertain 



aUBLIHATION. 



■ C ^ 




when he perceives a metallic film on the glass, whether he is to 
attribate it to aiBenic or to lead. 

OoDWOuently, flint gUsa, which is known by tts heaviness, its 
easy fiidbilitf in the oxidating flame of the blowpipe, and its 
equally e*y decompoaition, (manifeated by the appearance of a 
budc fihn of met&llic lead,) in the reducing flame of the blow- 
pipe, is t« be rejected in choosing or making glass tubes for sub- 
umation. The best sort of glass for operations of this character 
is the bai^ white glass which ia made in Bohemia. 

(6) Preparation of the Tubet. — They must be cleatttd. Tow, 
Motting paper, or a bit of soft silk handkerchief^ introduced and 



aUBLIMATlON. 105 

turned about by a wire or a slip of whalebone, mostly answer 
the purpose. They must be dried. You warm them and Buck 
air thiDugh them. See page 90. 

(c) Bulk of the Charge. — Thia is regulated by a Tariety of 
circumstances- In expetimeittB upon Arsenic, the quantity sub- 
mitted to examination is frequently but a small portion of a 
grain. In miscellaneous experiments, such as those of deter- 
mining whether or nut a substance is volatile, or gives off water, 

Oor acid, &c., the quantity of matter need not in general be 
more thui will lie upon the circle in the maivin. 

(d) Imertion of the Charge. — The substance which is to be 
submitted to sublimation requires to be conveyed to the bottom 
of the tube without soiling its tidet. If the tube is more than a 

Juarter of an inch in diameter, the substance, prerioudy pow- 
ered and mixed with its flux, if any is requisite, can be inserted 
by means of a gutter of glazed post paper, in the manner de- 
scribed at page IG. If the tube is lees than a quarter of an inch 
in diameter, such a method of inserting the charge is not easy. 
For example, it is impossible to convey a charge by means of a 
gutter of paper into tne bulb of the third tube figured p. 104, 
without soiling the narrow neck that leads to the bulb. In these 
cases, the charge is to be first pushed down into its place by a 
platinum wire, or a bit of stick, and the tube is to be cleaned 
afterwards, while held in a vertical position, so as not to displace 
tl)e charge. The cleanii^ is to be effected by means of the arti- 
cles named above, or when the tube is too narrow to admit of 
these, by means of a needle and thread. The thread is put 
tlirough the eye of the needle, and afterwards coOed round it, 
like the tlireaib of a screw. You hold the needle by the point, 
and clean the tube by rubbing it with the thread wound round 
the other end of the needle. 

(e) Use of Test Papers. — When the disengagement of ammo- 
nia, or of acid vapouts, is anticipated, it is necessary to prepare 
the tube with test papers. If ammonia is expected, red litmus, 
turmeric, or cudbe^ is to be chosen. If an acid is anticipated, 
blue litmus is to be used, except in testing for hydrofluoric acid, 
which requures Brazil wood paper. The twt paper must be 
folded or cut narrow enough t« go into the tube; it must be 
moistened with pure water before it is inserted, because dry 
gases do not act upon dry test papers; and the end of the paper 
must project from the tube, and be turned over the edge, to 
prevent its slipping too for in and becoming burned. When it 
IS uncertain wnat sort of vapour will be disengaged during the 
process, a siip of turmeric, and another of blue litmus, may be 
put in side hy side, so as to detect cither acid or alcali. 

When water sublimes and condenses in the upper part of 
the tube, the test papers are employed to ascertain whetner the 
water is acid, alcaline, or neutral. 

Leaves of the Uttle test books, represented at page 47, are 
very convenient for this use. 



106 . SUBLIMATION. 

(/) BupporU for the Tube in the Flame— T\ie finger and 
thnmb— rarely any thing else, except when you perform Bnbli- 
mation in a tube for the purpose of preparijif a quantity of a 
sublimate, and not ainiply t« aacertain the fact of Bublimation, 
~ir the nature of the lublimate. 



(g) Expomre qf the Tvbe to the Flame. — The tube is first 
gently wanned all Over by waving it at a distance above the 
name of the spirit lamp. It is then brought close to the flaiue, 
and finally, the bottom where the charge ia placed is held in ^e 
hottest pMl of the flame. The potitvm of the tube may range 
from the horizontal to the vertical. The greater the heat that 
the substance requires to volatOe it, the more upright must the 
tube be held; and when the substance is one that nses, like 
water, at a low heat, the tube muat approach the horizontal 
position. It ia advisable to begin by holding the tube nearly 
horizontally. If the substance rises, it is well. If not, the tube 
may be rawed. Were you to reverse this arrangement, and to 
be^ by hoiding the tabs in a nearly vertical position, then if 
water were produced, it would run down from the cold to the 
hot part of the tube and crack it. If you happen to know the 
nature of the charge, then it is advisable to hold the tube verti- 
cally in subliming a compound of difGcult sublimation, such as 
calomel, arsenic, or Bulphuret of mercury; and horizontally in 
subliming iodine, camphor, corroure sublimate, and othets of 
more ready volatility. In the event of no action taking place 
after a tube has_been ft* a few minutes exposed to the strong- 
est heat of the spirit flame, it becomes necessary to urge the 
flame with the blowpipe. 

(h) Preparation ofhubRmatei in Tubet. — In the case alluded 
to at (/), of eubliniing in quantity, the tube is commonly taken 
of a targe size, uid may be supported by the tube holder de- 
scribed at page 43. A short wide tube may be placed over 
the mouth of the subliming tube, to prevent the escape of the 
vapours; and the condensation may sometimes be facilitated by 
the application of wet blotting paper or tow to the upper part 
of the tube. 

ti what C8»e* Tubee with Bulbi are jrumt useful. — When 
mce is to be tested for water, or other incombustible 
volatile compounds, a bulb tube is to be employed, because the 
volatile matter rises most readily when the air tias room to cir- 
culate in the vessel. When, on the other hand, you have to 
. sublime combustible substances, such as arsenic or sulphur, a 
narrow tube is required to prevent combustiou. 

EXERCISES AND CLASS EXPERIMENTS. 

I. Spread > uiull quaalitT of giauly-powdered gum-beaioin on the 
bottom of a poreeliln bagin, iavert over it a gliw tumbler, sad apply to 
a Kentle heal bj meaiu of the lamp-furnace: (he gum will melt, ai 

deiue Tamea wul ImmedUtel; rue from it and dej " " '" 

the tides of the glass Id beautiful >ilky cryalals of beni 



(0 In al 



DSB OF THE BLOWPIPE. 

2. T»ke ■ iai^ gl»" jar, conuining »t iti lop * tpriB of 
Totamuy or Mme inch •hrab, ind iOTert it oier ■ Ibt thick 
piece of heated irOQ on which eouM ponder of gum-beo- 
lotn bu jiwt beea spread — then, the benioic add which 
sriHB, H in the preceding eiperimeal, will be dapoailed on 
the branches of the shrub, producing a lingular and beauti- 
ful repreaentation of hoar Irost. 

3. Sulphur may be distilled l>j mblimBlion, nilns a re- 
tort with a very ihort neck joined lo a receiver. See tho 
article ••Diilillatlan." 

4. Powdered indiiroi gently heated over the tpirit lamp ^ 
between two watch Rlauea or tin captnlea, lublimea in very 
icdendid copper- coTourod erystaU. The upper captule 
should bo cooled by the application of wet blotting paper. 

6. Take two parts of marble, and one part of muriate of ■ 

Puherise them separately, and mii the whole intimately together. Put 
the mijlure into a Florence flajk. and put the neck of the Saik through 
a cork Into a receiver or large tube. Heat the (lajk by a lamp, and cool 
the receiver by wet paper. Carbonate of ammonia will lublime and con- 
deoae in the lolid state in the receiver. 



1. Pnl agnin of iodine into a imall flask, or glasi lube, and apply 
heat, ^lendid violet vapoun of iodine loon SI] the tube. Vben- the 
anblimation of iodine is effected slowly, crystals are fbrmed. 

8. Sublime a grain of cinnaliar in a tube one-lbiid of an inch wiJe> 



10. Put A grain of red oxide of mercury into a very small glass tube, 
and appl; heal till the red oxide ii entirety volaliliied. Metallic mer- 
cury will condenie on the (idei of (he tube, and oxygen gas escape at tlio 



USE OF THE BLOWPIPE. 

In many experiioenta, it is of great importance to lie able to 
expose emallsubstances to, a veiy high temperature. For this, 
it IS necessary to employ the blowpipe, an instrument with which 
a current of air ia blown into the flame of a lamp or i^andle, 90 
as to give one the power of producing in a moment, the most 
intense heat of a powerful furnace. You can easily perform, 
with the help of this little instrument, the experiments which 
are necessary to determine the chemical nature of many differ- 
ent su1>stancee. You can produce any temperature up to a 
white heat, and direct the hot flame upon any subst&nce you 
wish. — Many advantages are deriTed from the use of the 
blowpipe. Its smallni'M and cheapness are no inconsidprable 
recommendations. The mOst expensive materials, and the 



108 OSB OP THB BLOWFIPB. 

minutest Bpedmena of bodies, mar be used in these experiments ; 
and the whole process, instead of being carried on in an opaque 

Itii ' , 

ceming Che qaaniitie* of products; but ir 
ledge of the components of any object in a great acquisition, 
which knowledge is thus obtained in a very short time, and 
serves, at all events, to show the best and least expensive way 
of condilcting processes with the same matters, in the larger way. 

DESCRIPTION OF THE BLOWPIPE. 

Thk blowpipe is a tube of brass, about seven inches long, 
and one-fourth of an inch in diameter at one end. It tapers off 

Vto a fine point at the other end, where the 
orifice is about the eightieth part of an inch 
in diameter. This point is bent on one side, 
and the tube is fomished mth a cylindrical 
, reservou' to hold the water which air, blown 
* from the mouth, deposits in the tube. In 
using the blowpipe, the open end of the long 
tube is put into the mouth, the instrument 
being held in the right hand. Air in a 
continuous current is then gently blown 
thronffh the tube, the narrow point of which is held against the 
side of the flame of a candle. Thereupon the upright flame of 
the candle is thrown into a horizontal or even into a descending 
direction, and at the same time is diminished in bulk and 
greatly increased in Us power of i^ition. The substance which 
IS to be heated is supported by instruments held in the left 
hand, and is immersed in the deflected flame of the candle, 
which is colled the blowpipe flame. In looking at the figure, 
you are to suppose the point m to be in the mouth of an opera- 
tor placed opposite to yourself. 

If you do not possess a blowpipe of the above form, you may 
employ a common brass goldsmith's blowpipe, which costs six- 
pence; but it is much more convenient to nave a blowpipe with 
a reservoir, for the common sorts are veiy inconvenient. A 
good and cheap blowpipe may be prepared as follows:— Take a 
glass tube, eight inches long, three-eighths of an inch wide, and 
one-twelfth of an inch thick in the glass; bend an inch of it at 
one end at a right-angle, taking care to make the bend so car»- 
fiilly as not to obliterate the bore of the tube. The heat of a 
spirit lamp is sufficient to soften the glass that is to be bent. 
Next, take a piece of tube, two inches long, one-fourth of an inch 
thick, and one-twelfth of an inch in the bore; hold the point in 
the fliune of a spirit lamp, continually turning round the tube, 
until the opening is contracted to a hole sufficientlj^ email for 
the orifice of a blowpipe; bend this small tube at a right angle 
in the middle, and adi^t the other end of it, by means of a cork. 



OSH 0» TUB BLOWFtPB. 



t« the bent end of the larger tnbe. The point should be vith- 

ool very gradually, that 
s otherwiBe liable to scilit when 



drawn from the flame and Buffered to c 
it may be well annealed. 

presented la the flame afterwards as a blowpipe. IHis la tbe 
beet of all the Tarieties of glass blowpipes. No water efcapes 
from the jet. New jets areeasily made when required, without 
Ute asRstance of a glass blower. And the form and move- 
ments of the jet are sach as to allow the blowpipe flame to be 
directed in any direction that may .be required. 

All the above varieties of the blowpipe are, however, greatly 
inferior to that which 1 shall describe next, a variety which, 
being very simple in its conBtmction, not easy to put out of 
order, effectual in use, convenient to handle, and very low in 
price, pOEBeseeti the advantages of most other blowpipes combined. 



d, b, is a conical tube of japanned fin plate, | of an inch wide 
at the broad end, and J of an inch wide at the narrow end, 
which is surrounded by a ring of solder that fbnne a knob or 
button J of an inch in external diameter. The naiTOw end of 
the tube is open, tbe wide end is closed, c is a brass pipe, 2 
inches long, and | of an inch in diameter, adapted by grindmg 
to a socket that is soldered into the ade of the conical tube near 
Its broad end. d is a brass tube or cap, ^ of an inch long, fitted 
by grinding upon the point of the tube c, and having at its other 
end an orifice of about the eightieth of an inch in diameter. All 
the joints of the instrument are made air tight, so that when 
air is blown in at tbe narrow end of the tube b, it can only- 
issue forth at tbe small orifice in the jet d. 

The length of tbe conical tube should be about seven indies. 



110 USB or THB BLOWriPB. 

The reason that I Bay about geren inches is, that, in &ct, the 
proper length depends upon the eye of the operator. A mbstanc* 
tnibmitted to examination before the blowpipe, must, duriiig the 
experiment, be placed at that distance ^m the operator's eye at 
which he has the most distinct vision. Consequently, the length 
of the blowpipe must he regnlated by the strength or weak- 
ness of hisaight . Those which are made fot sale at my suwegtioB 
are seren inches long, and I find them to answer very weR. But 
in Edinburgh they make blowpipes of the eDormous lengtii of 
ten inches, though I cannot conceive any purpose for which 
they can be employed, unless it he glass blowing. Every person 
must adapt his blowpipe as he would his spectacles, to suit his 
own siglit. If he procures one of the blowpipes here described, 
and finds it to be too short, the knob of solder b, can he melted 
oiF, and be replaced by a lengthening mouth piece, made of tin 
plate, wood, ivory, or, what the owner can in general most 
readily himself adapt to the instrument, a bit of glass tube. 

The essential parts of this blowpipe are represented in the 
following diagram in their full »ixe. Nothing is omitted, ex- 
cepting the middle part of the long tube. The bottom at the 



mouth b is here shown distinctly. The use of it is to prevent 
the too ready flowing of moisture from the lips into the tube. 
The brasspipe cisshownapart (in outline), and also in itspropcr 
position. The socket by which it is connected with the main 
tube, is a brass tube of half an inch in length, soldered in such 
a manner to the main tube, that half its length is within, and 
the other half without the main tube. The use of this socket 
is to afford the opportunity of taking the blowpipe to pieces for 
packing ; hut when the blowpipe is not for a traveller's use, the 
socket may be (Hspensed with, and the pipe c be soldered to the 
main tube a, in place of the socket. 

It is essential, in the construction of a good blon^tipe, to fix 
the pipe c at right angles to the axis of the main tube a b. In 
giving this opinion, 1 cannot avoid leferring to the descr^tion 



UBB OF THX BLOWPIPB. Ill 

ftnd figure of a blowpipe, giren by a celebrated Edinbiuvh 
chemist, Dr D, B, Reid, SudimenU of Chemistry, page 90. He 
directs it to be loade ten inches looff, and represents the pipe c 
as branching out at an angle of 55° from the axis of the main 
tnbe, BO as to point away from the operator. He dispenaes with 
the nozzle d, and directs the orifice of the pipe c to be the 40th 
of an inch in diameter. 1 have seen a blowpipe made upon this 
plan, and lest any person should be misled by a public recom- 
mendation of them given by so celebrated a teacher as DrKeid, 
I think it right to say, that such a blowpipe is wholly unfit for 
use in chemical analyBis. Ita defects are these: — 1. it ia heavy 
and awkwu^. The orifice is too large, and when it becomes 
stopped with dirt, it is, from want of the small nozzle d, difficult 
to clean. 2. It blows the flame in such a direction upon the 
substance which is exposed to its action, as to drive the volatile 
products of the operations effectnally away from the operator's 
nose. Yet one of the principal reasons for using the blowpipe, 
is, that it produces several volatile products, the odour of which 
indicates the nature. I need only name the compounds of 
sulphur, arsenic, and selenium. 3. From the length of the 
instrument, and the direction of the smaller branch, it becomes 
necessary to hold the substance which is to be heated at such u 
distaneefrom the eye, and in such a position in reference to the 
lamp, that it proves just as impossible to see the solid residue 
whudi the flame leaves behind, aa it ia to smell the volatile mat- 
ter which it drives away. 

Iretum to the description of a good blowpipe. The pipe c is 
terminated by the nozzle d, of which there are two figures, the 
lower one (that upon the pipe c) representing a section, the 
upper figure showing the outside of it. The parts are well pro- 
portioned, excepting that the orifice appears in the section larger 
than it ought to do. The proper diameter is the 80th of an inch. 
But I shul hereafter speak of the means of finding or making 
the proper sort of orifice. 

There is fixed upon the pipe c, a round cork, three quarters 
of an inch wide, and one inch long. It must fit the pipe pretty 
tight, so as not rcadUy to shift about. The pipe passes through 
the centre of the cork. The use of the cork will be explained 

Eresently. It answers best when it is shghtly conical, with the 
roader end turned towards the nozzle d. 
When the blowpipe is not in use, it should be hung on a nail 
fixed in the wall, the head of the naU passing between the cork 
and the m^n tnbe a. 'Die moisture witnin the tube then 
escapes at the end b. 

This blowpipe is sold in Olasgow for one shQling. I pasa 
over every other sort without notice ; for there is none better 
tlian this, though there are many twenty times dearer, 
commonly called Dr Black's blowpipe, but it was the inve 
of a German workman who lived m Qla^w. The instrument 
which Dr Black used, was made by Mr Crichton, the ther- 



1 12 USB OF THB BLOWPIFK. 

mometoc maker, t« whom Dr Black took the fbreigner's blow- 
fipe for a pattern. Mr Crichton always afterwards used a 
Mowpipe of this description ia blowing the bulbs of his ther- 
mometers. 

THE PROPER KIND OF COMBUSTIBLE FOR THE FLAME. 
A' CANDLE with a thick wick may be occasionally employed, but 
it is by no means a convenient or a profitable combustible. It 
does not alwaya give a sufScient heat, and is besides subject to 
the inconvenience of being melted by the radiant heat from the 
substance under examination. 

When a candle is used, it should be snuffed rather short, and 
the wick turned on one side towards the object, so that a part 
of it may lie horizontally. The stream of air from the blow- 

tipe must be blown along this horizontal part, as near as may 
e without striking the wick. If the flame be ragged and irregu- 
lar, U is a proof that the aperture of the nozzle is not rounder 
smooth ; and if the flame have a cavity through it, the aperture 
is too la^e. When the hole is of a proper figure and duly pro- 
portioned, the Same consists of a neat luminous blue cone, sur- 
rounded by another flame of a more faint and indistinct appear- 
uice. The strongest heat is at the point of the inher flame, or 
between a and h, id the figure on page 108. 

Oil. — Next to gas, of which I shall speak presently, the best 
thing to use as a eombustible for the blowpipe flame, is Sweet 
Oil, or DKorpiNos of Sweet Oil, burnt in a lamp of the following 
description, which is the blowpipe lamp recommended by 
Bebseuus: — It consists of a tin plate cylinder, one inch wide, 
and four inches long (^aj. At t is a 
wick holder, three quarters of an inch 
! across, for holding a flat lamp wick. 
"] This opening can be closed by a screw 
cap. c represents a little cylinder, 
fastened to the end of the lamp. This 
cylinder holds a perforated cork, 
^fwhich admits the rod C^J of a little 
retort stand, f such as is represented at 
page 36.) The lamp can be raised on this rod to any height the 
operator finds convenient. — The stream of air is blown along 
the top of the flat wick, and 
not across it. The flame is 
powerful, and at the same 
time much under the com- 
mand of the operator. 

The subjoined cut explains 
the method of supporting the 
lamp upon its stand, and the 
relative positions of the blow- 
pipe and subject of experi- 
ments when in action. 





,o3lc 



UBH or THX BLOWPIPE. 1 13 

I alioll here add a description of a blowpipe lamp, which I 
have Bomewbat altered from that of Berzelius, and which is now 
made for sale in Glasgow at a cheap 
rate, {the price of it ia eighteen 
pence.) I'he bodv of the lamp ia 
like that of Berzchua,of the ohlong 
form, butitseross section ia a Bquare 
iuatead of a circle. It is made of tui 
plate and japanned. The annexed 
figures represent aview from alrave, 
and a view of the fore end. — a re- 
preaents the body of the lamp, 
which ia 3^ inchea long', and 1} 
inch square, b is the wick holder, 
which, as shown in the elevation, 
is cut aslant at top, bo that the sur- 
face forms an angle of about 30°, 
with the top of the lamp. The 
lowest end of the top of tne wick 
holder rifles a little way above the 
neck of the tamp, which ia ^ inch high. The size of the orifice 
of the wick holder is shown by the third fig^ire c. An oval 




dd,producingasemi-circalar projection 
on each side of the lamp, of about half 
an inch in width. The use of these 
projectiona is to aupport the hands of 
.__ the operator during an experiment. At 
e ia represented the tin cylinder, by 
means of which the lamp is held upon 
the rod of the retort stand. The cotton 
for this lamp can be purcliased in lone 
flat pieces, woven like tape, and, I believe, technically termed 
half-inch cotton aick. In trimmina' the lamp, take two pieces of 
this cotton wick, each six inches long, soak them 24 hours in 
stroDK vinegar, drv them before the fiK, and put them smoothlv 
and side by side tnrough the wick holder. Preserve the stock 
of cotton wick, wrapped up in several folds of brown paper. It 
willnot bum well if left carelessly about in dirty comers. When 
the l%ht is extinguished after use, the charred wick should be 
immediately cut off by Hcisaors level with the diagonal surface 
of the top of the wick holder, so aa always to leave the wick in 
a state fit for uae. There must never be any charcoal on the 
wick when in use, nor any ragged edges or loose threads. The 
wick must not be pullcil too high out of the holder, otherwise 
it will smoke, nor muflt if, be too short, otherwUe it will give 
too little heat. , 



114 irax 07 THB BLOWPSrB. 

The lamp hsa a cover to put on over the wick and preseire it 
from dirt. Bnt as the lamp is not intended for travelling, the 
cover ia not made to screw on like that of Berzelius's tamp, 

Oas.^ — If you can bring a gas light to tha 
table where you are accnatomed to perform" 
chemical experimeuts, yuu need seek for do 
other flame for the use of the blowpipe. Yet 
its convenient use requires a little msni 
ment, for the "aingle jet" or burner t 
one small orifice, furnislied to 
of gas by the gas company, while it aflbrds 
a suflicient flame for blowpipe use, only does 
o when under a preeauTe which sends the gas 



'f^ 



This inconvenience is obviated by the em- 
plo3anent of a burner of the form and size 
figured in the margin, q 6 c ia a front view 
of the burner. The neck, a, h exactly sinular 
to the neck of the "single jet bumers'of the 
gas company, and of course is adapted to fit 
the nozzles of all common gas pipes. Above 
this neck is a, flat pipe, terminating in an 
orifice of the size shown by the second figure, 
+ e. The top of this pipe is cut aslant at an angle of 40° from 
the horizontal, as shown by 6 e in the upper figure. A slight 
hollow is made at each end of the orifice, as shown at x c. When 
the bomer is used for chemical experiments, it is placed in the 
position here represented, with the nigh comer to the right hand, , 
and the stop cock is opened till the gas flame, when not acted 
npon by the blowpipe, gives about as muck light as a taUow 
candle of six to the pound. When used for gl^ blowing, the 
burner is turned half round, so that the end, c, 'm placed f^hesc 
from the operator. The flame is then to be increased in size, by 
turning the stop cock as tor as is found to be necessary. 

The form of Dumer best adapted to render gas of use in blow- 

?ipe operations was determined by a set of experiments made 
y Professor Clihk of Aberdeen and myself, with thiit view. 
We procured burners with orifices of different forms, and fixed 
them upon gas pipes where they could be turned round hori- 
zontally and vertically. We thus produced a great variety of 
different gas flames, from which we selected the flame that could 
be most efFectively acted upon by the blowpipe, and at the same 
time be kept under the most complete control. 

HOW TO PRODUCE THE BLAST OF AIR. 
When you are going to operate, you sit with the lighted lamp 
before you, and nearly level with your mouth. Yon hold the 
blowpipe in your right hand, and putting the upper end info 



tJSK OF TSB BI^WFIPX. 115 

'yonr moath, yoii approach the point to the flame of the lamp, 
and-Wow gently through the tube bo as to keep the flame con- 
tinually deflected, 

' There is an arti&ce in the blowing through this pipe, which 
13 more difficult to deacribe than to acquire. The effect intended 
to be produced is a continual stream of air for many minutes, if 
neceasary, without ceaaing. This is done by applying the tongue 
to the roof of the mouth, bo as to intcrrapt tne communication 
between the mouth and the passage of tne nostrils ; by which 
means the operator is at liberty to breathe through the nostrila, 
at the same time that, by the muBcles of the lipa and cheeks, tie 
forces a continual stream of air from the antorior part of the 
mouth through the blowpipe. When the mouth begins to be 
empty, it is replenished by the lungs in an instant, while the 
tongue is withdrawn irom the roof of the mouth, and replaced 
again in the same manner as in pronouncing the monosyllable 
ttit. In this way the stream may be continued for a long time 
without any fatigue, if the flame be not ureed too impetuoualy, 
and even in this case, no other tatigue is felt than that of the 
muBcles of the lips. 

I. The jirstthmg that a beginner has to do is to accustom him- 
self to breathe freely through the nostrils while his lipe arc kept 
firmly closed. 11. This b^ng effected, he should fill nis moufn, 
with BU-, by allowing his cheeks to distend as the air arriTes 
through the posterior nostrils. 111. He should then make two 
or three moderate in^irations and expirations by the nostrils, 
without opening h'a lips, or suflering the air to escape irom bis 
mouth. All this may be learnt with a very little practice. IV, 
When the learner has effected this much, he should introduce, 
between his lips the button, or mouth piece of the blowpipe, 
B&d then, having filled his mouth with air, he should force it 
through the blowpipe against the flame of the lamp, by the 
action of the muscles of the cheeks, while he continues to breathe 
without interruption through the nostrils. To some persons this 
is difficult, but frequent tnals BOon establish the habit of ])ro- 
ducing a continuous blast. It is tike the difficulty of turning 
round the right arm and right leg in contrary directions at the 
same moment, which can lie done after some practice. 

HOW TO PRODUCE A STEADY JET OF FLAME. 
Havihg, by the observance of the foregoing directions, accom- 
plished the first object of keeping up a steady blast, the next 
thing t» be attained is the power of producing a steady jet qf 
fiame. The latter cannot be produced without the former, but 
a steady blast may be blown without producing a steady flame, 
. either from some defect in the lamp or in the orifice of the blow- 
pipe, or from want of steadiness in the hand that holds the 
blowpipe. 

Dkfeois in the Lahp. — 1. Bad oil, such as fish oil, or even 
Bweet oil that has reniained long in tiie lamp and become thick. 




116 DSB OF THK BLOWPIFI, 

2. Dirty cotton, or an untrimmed wiek. A pair of sciasora and 
a ptui of iron or brsBa pincetB witti tine points, should be in 
readineas to remove cliarcoal from the wict, and keep it clean 
and eren. 8. A dirty wick holder. A common defect when 
the lamp has been Home time oot of use. — A clean lamp, clean 
cotton, and limpid oil, ore indispensable requisites. 

UNaxKADiNKsa or Hand, — I have said that the blowpipe, is to 
be held in the right band. To this I may add, that it is to be 
held by U)plying the thumb and forefinger of that hand to 
opposite sides of the cork which is fixed on the cross tube of 
the instrument. The thumb is to pass behm the blowpipe, and 
the forefinger above it. Tlie little finger of the same hand is to 
be lodged on d, the semi-circular platfonn affixed to the under 
side of the blowpipe lamp for this purpose. The second and • 
third fingers are to be brought in between the cork and the 
little finger, so that the upper tide of the first joint of the middle 
finger may press agunst the nnder side of the oaAi. The hand 
is thus half cloeed. If the point of the 
blowpipe is now held aeainst the end of the 
wick, the relative powtiona of the blowpipe 
and lamp will be snch as are shown in the 
marginal figure, where a is the lamp, b 
the Dlowpipe, somewhat foreshortened in 
the drawing, and c an object exposed to the 
blowpipe flame. If the operator has fixed his 
lamp iirmiy to its support, and placed it 
beforehim m the position formerly prescrib- 
ed, the lUadinesi of the blowpipe is now 
put entirely under his controul. 
DBFEcTBtNTHROiuFroB or TBE Blowpipe, — They areas follows: 
too small a hole ; too lai^ a hole : a misshapen hole : stoppage by 
dirt. 

In trying a blowpipe, you are to hold it in the manner just 
described, to enter the point of it the eighth of an inch into the 
fiame, and the eighth of an inch above the wick, and to blow a 
current of air through the flame and parallel to the surface of 
the wick. 

If the air deflects the whole mass of the lamp flame, and 
fi>rms a horizontal blue cone of flame which converges to a blunt 
point at about an inch from the wick, with a larger, longer, and 
whiter flame enveloping the blue flame, and terminating at a 
point beyond the blunt point of the blue cone, then, the blow- 
pipe is perfect. 

If it produces a very small horizontal flame, and leaves the 
greater part of the lamp flame in its usual vertical position, the 
orifice of the blowpipe is too small, or is misshapen. 

If it produces a large white rough-pointed flame, which makes 
a roaring noise, or if it throws out a iMge white unpointed flame, 
with apparently a hole through the middle of it, then the orifice 
of the blowpipe is too large. 

I,.n .ll,G00glc 



DSB or THB BLOWPIPS, 117 

If it produces a blue cone of fiame, with straggling white 
Ught on one aide of it, the orifice is either dirty oi out of ghape. 

To make an inBtmment for cleaning the orifice of a blowpipe, 
take a very small sewins needle, fix tho head of it into a cork, 
to eerve as a hiindle, and grind the aides of it for an inch from 
the point, upon a smooth stone, with oil, till you have converted 
it into a cutting tool with three edges, ^milar in shape to a 
ttiutgular file. With thia too), you remove any dirt that may 
be in the orifice of the blowpipe, in which you turn it round 
veiy gently, so aa not to cut tlie brass of which the noz^e is 

Bnt if the hole, after being cleaned by this means, proves, 
upon trial, to be still too small, the same instrument is employed 
' to cut it larger. In this case you must be careful to insert the 
needle into the orilice through the inside of the nozzle, and not 
from without. If any burr or roughness is produced on the 
outer extremity of the orifice by this widening, it must he re- 
moved by a fine file. The-hole must be quite round and quite 
smooth both within and on the external edge. 

If the orifice is too large, the nozzle is to be placed with its 
open end, or milled rim, upon the face of a small anvil (page 
4), and the point is to receive five or six gentle strokes with a 
hammer, which commonly bring the sides of the orifice closer 
together. If thia does not sufSce, a few gentle strokes may be 
given to the sides of the nozzle close to the orifice. It ia 
necessary to make the hole rather smaller than is proper for 
use. The cutting tool ia then inserted and turned round in the 
hole, and after suitable widening the burr is removed from tho 
exterior by the file, in the manner already directed. 

In the operatbn of reduction it ia necessary, as will be ex- 
plained in the next section, to have a blowpipe with a snail 
orifice; while in the operation of oxidation, one with a large 
orifice is useful. It would therefore, apparently, be convenient 
to have two nozzles with orifices of different wzes adapted to 
the same blowpipe ; but these operations frequently follow each 
other in suchrapid succession that it ia found to be inconvenient 
in practice to exchange the nozzlea even when they are ready 
for use, and it is usual for the chemist to content himself with 
one nozzle only, and that with a small orifice, for it is much 
easier to oxidise with a small orifice than it is to reduce with a 
large one. 

It will he readily inferred, from what has been said, that 
when the orifice of the blowpipe is misshapen, it must he treated 
as if it were too lai^, namely, it must be hammered together 
and opened anew. 

As the triangular needle is oilen required for cleaning the 
blowpipe, I adapt lis cork handle to the mouth of a small test 
tube, which thus becomes a case for it. 



t, Google 



lis USB or THE BLOWPIPB. 

HOW TO EFFECT OXIDAION AND REDUCION. 
When you have learned to produce a steady and continuoos 
jet of flame, your next business is to study the properties of its 
different parts, and the means of employing or of modifying 
those properties. You have, for example, to learn which is the 
hottest part of the flame, which the part that is qualified to 
communicate oxygen to a substance, and which the part that 
serres best to take oxygen away, or to reduce a metallic oxide to 
the state of a metal. 

Thb pabm of \ VEaucAL Flame,— Examine the flame of a 
candle attentively. You will pei-ceive near the 
bottom a dark blue portion, a c, which gradu- 
ally diminishes in size as it recedes from the 
wick, and disappears when it reaches the per- 
pendicular side of the flame. In the midst of 
the flame, yon observe a dark portion, a d, 
which is enveloped in a brighter shiuing por- 
tion of the flame. The dark part consists of 
combustible gases, as they rise from the wick, 
still unmixed with oxygen, and consequently 
unbumed. Around tlie whole portions already 
. mentioned, you will, on close examination, ob- 
serve a thin coating of scarcely visible flame, 
c e c, which is largest at the apex e. It is in. 
this outer coating that the mixture of the 
combustible gases with the oxygen of the air 
takes place — where in fact the burning is effect- 
ed — and where you find the greatest heat of the 
flame. You can text this fact by the insertion of a fine iron 

Ths Oxidatiho Flame. — Put the point of the blowpipe about 
the tenth of an inch into thejlame, and about as much above the 
ootUm. Blow a current of air gently and steadily along the top 




of the cotton, parallel to its surface, but without touching it. 
Blow strong enough to keep the flame straight in the direction 
of this blast, but be careful not to blow any stronger than it 
absolutely necessary for that purpose. B^rinners commonly 
Wow much too violently. Upon examining the blowpipe flame 
thus produced, you wiU observe a long blue cone, a e, converg- 
ing to a blunt point at about an inch from the wick, and sur- 
rounded by an external flame, brownish, vague and indeter- 



I7» OF THB BUWPIPK. 119 

mined in its form. The inoet intense d^ree of heat is at the 
point of the blue flame e, or between that point and the point 
of the outer flame. This point e ia equivalent to the point e at 
ibe summit of tlie Tertical flame, or rather to the surface c e c 
of the vertical flame ; for, in the latter, oxygen being supplied 
to the combustible gases all round the flame, the heat resulting 
from the combustion is spread over a large surface ; hut in the 
blonpipe flame, active combustion takes place at a single central 
point in virtue of the oxygen forced into the middle of the flune 
by the blowpipe, and it is at that single point that the heat of 
the flame is concentrated. Hence, the blowpii^e flame has the 
power to oxidise, reduce, melt, or vaporise, ijodies upon which 
the vertical lamp flame is without action. 

It is not, however, at the hottest part of the flame that the 
process of azidaiion is effected. It is not indeed in the flame at 
all, but at the point b beyond it, where this phenomenon occurs ; 
and the oxidation takes place the more readily, the further the 
combustible body is removed from the flame, provided always it 
he kept vvithin reach of a sufficiently high temperature. You 
have, in performing this operation, to take care, as 1 before ob- 
served, not to blow too violently. If you force more air into 
the flune than it can consume, you afbrd a superfluous current 
of air, which is not required for the support or even the deflec- 
tion of the flame, and which serves only to cool It. Too strong 
a blast is also injurious to the process of on idation, especially when 
the assay is placed upon charooaL In general, the operation 
goes on best when the substance to be oxidised is kept at a dull 
red heat, — when the blue cone is free from stragghng rays of 

EUow flame,-~when the blast is temperate, — and the blowpipe 
a a somewhat larger orifice than usual. 

The Reducino Flaue. — In order to produce the oxidating 
flame, the blast is blown into the very centre of the vertic^ 
flame, which becomes in a msnner turned inside out. On the 
contrary, the reducing flame is little more than a deflected ver- 
tical fl^e, if I may use so paradoxical an expression. 

To produce the reducing flame, you must hold the blowpipe 
higher above the wick than you do to produce the oxidating 
flame, and you must not now allow the nozzle to enter so faj 
into the flame. I diall presently sketch the position of the in- 
strument in the margin. You should use the nozzle with a 
smaller orifice than is required to produce the oxidating flame, 
and, in tlus case, yon should blow a little stronger than you need 
to do to produce the oxidating flame. The wick must be smooth 
cut, free from charcoal and loose threads. If must not be pulled 
up too high, otherwise the blowpipe flame will smoke ; nor too 
low, otherwise the flame will be too small to answer the purpose 
of reduction. The blast must be continued for a conaiderable 
time without intermisdon, otherwise reduction cannot be eflectetL 
It ia indeed chiefly for the purpose of performing this open- 




120 USX OF THE BUiwPirB. 

Hon, that the power of keeping up a coatiDuouB blait ia to be 
acquired. 

The blue flame was formerly considered to bo the redacing 
flame, but this is really not the case. It ia the illuminating por- 
tion of the flame in which the reducing power esists. When 
tlw blowpipe is held in the position deecribed above, the vertical 
flame is deflected entire and condensed into a small bright 
cylinder of fire, the point of which is surrounded by the some 
dunly visible portion of flame that ia discemable as a fringe in 
the vertical flame. 
If this brilliant 
blowpipe flame, 
which is the re- 
ducing flame, ia 
directed upon a 
bead of glass, fiiecd 
ontheendofapla- 
tinum wire c, and 
held at little more 
than half an inch 
from the lamp wick, the access of atmospheric air is completely 
cut off, and the bead is tnuronnded by the half-consumed com.- 
bustibte gases which compose the white flame. As the«e gases 
are strongly diapoaed to combine with oxygen, for the two rea- 
sons that they are very hot and that they are combuatible, it is 
found that any oxidised aubstance present in the head ia very 
speedily deprived of a portion or of the whole of its oxygen, or 
it becomes what is technically termed redaeed. So also when 
metallic oxides, supported on charcoal, are held in this flame, 
their reduction is effected with great r^dity, the operation 
being in this case &cilitated by the reducii^ powers of the red- 
hot charcoal. 

Substances that are easy of redaction can be reduced by the 
blue flame, if they are supported upon charcoal ; but, in general, 
it is only the illuminating flame that acta as a reducing power. 
There ia frequently some difficulty experienced by the leamer 
in effecting the operation of reduction properly, but to effect 
oxidation is ao easy that one need merely to he told how it is to 
be done, to be able immediately to do it. The power to pro- 
duce at will eitiber of these phenomena must be cultivatea till 
it is acquired. 

The oxidating flame b sometimes rooken of as the outfrflame, 
and the reducing flame, as the tnn«r flame. 
MEANS OP SUPPOETING OBJECTS IN THE FLAME. 
YoD examine, by meana of the blowppe, whether substances 
are volatile or not ; whether they become decomposed by heat 
or not ; what are the products of their decomposition ; whether 
they are fnsible or not ; what phenomena tfiey exhibit when 
ftised with other subslances ; and bow they act when heated so 



USB OF THS BLOWPIFB. 121 

as to be oxidised ot disoxidiaed. Yon must be provided, there- 
fore, with means of supporting objects in the flame, which shall 
tbemselyea he able to resist the action of the flame, which, for 
example, shall neither volatilise, nor fuse, nor become decom~ 
posed, nor oxidised. Unless the supports be of this kind, their 
power to support soon ends in their destruction. We are, how- 
orer, unprovided with any one material of which to niake sup- 
ports ad^ted for all purposes. But we have the convenience of 
several mat«rials adapted to different modes of experimenting, 
the most important of which are glass, charcoal, platinum, and 

Nahrow GtASB Tubes open at both bndb. — There are experi- 
ments in which a substance is roasted (heated with free accMS 
of air) in order to ascertain if it is able to disengage certain de- 
scriptions of volatile matter. This operation is performed in 
glass tubes, open at both ends, and of abont i inch internal dia- 
meter. The sort of glass best fitted for this operation is hard 
white glass, made with potash, and free from lead. If this can- 
not he got, pate green glass is the nest best materiaL Flint 
glass contahiing lead is wholly unfit for the purpose. 

The substance to be examined is placed withm the tube, and 
close to one end. The tube is then exposed to heat in an in- 
clined position, with that end lowest where the assay is placed. 
Accordmg as more or less heat is required, the spot wbere the 
substance rests is heated by the flame either of the spirit lamp or 
the blowpipe. In general, it is beat, first to apply the spirit 
lamp, ana if the eiqpected result b not then produced, to fallow 
with the blowipe name. If the tube is held nearly horizontal, 
the current of air that passes through it is weak. If the tube is 
held in a nearly perpendicular powtion, the current of air is very 
strong. It is easy, therefore, to regulate the rapidity of the cur- 
rent according io the rate of oxidation that may be desired. The 
tiroducts of the combustion thus effected are cither gases or sub- 
imates. The method of discriminating them and ascertaining 
their nature will be explauied in a subsequent chapter, on 
" Analysis by the Blowpipe." I subjoin a figure of this little 
^paratus, and the mode of applying to it the blovrpipe Same. 




I , Google 



122 treB of tbk blovfpipb. 

The lengtbof the tube when first taken ibf thiaoperotkoi abonld 
be 6 or 7 inches. The ignition sfaeuld take placeat abont hdf 
an inch from one end of it, and after every experiment, the por- 
tion where the assay has rested should be cnt off with a file, and 
the remunder of the tube be csleaned for the next operation. To 
prevent the ialling out of the subject of experiment when the 
tube is held verti(»lly, it ia beat to bend the tube slightly at the 
point where the assay ia to be placed, namely, at half an inch 
from the lower end. 

Glass Tdbe closed at one end. — I hare described this instru- 
ment under the head of " Subluutioh," page 103. 

Charcoal. — The supports already described are of snch a kind 
as serve to expose an object to beat, while thev keep it out of 
immediate contact with the flame, enclosure bemg uecenaryfor 
the retention of the volatile products of the experimentt. But 
the support now under consideration is employed to present the 
assay directly to the action of the blowpipe flame, and with the 
freest access of air. The substance to be acted upon is simply 
laid upon the surface of s piece of charcoal and exposed to the 
blowpipe jet. Of course, volatile matter ia in this case dispersed 
in the air, and is only capable of detection when it produces an 
odour, or when it deposits a mbUmate upon the <£arcoal at a 
distance froiD the portion that is heated. 

The charcoal should be well burnt and fi«e from bark. It 
must not bum with flame, nor throw out sparks. Charcoal 
made from the wood of the pine, the willow, or the alder, is said 
by Berzeliua and others to answer the purpose better than other 
descriptioBB of charcoal. Such varieties aa contwn much iron 
among their ashes muat be avoided. For my own part, living 
generally in towns where I have no great choice of different 
woods, I take the chivcoaj that comes readiest to hand, and 
selecting the pieces that are well burnt, fr^e from bark and 
crevices, and tolerably heavy, I find them generally to anawer 
the purpose. In Glasgow, where charcoal is seldom used for 
fuel, it ia often dif&cult to be procured. It is however a by-pro- 
duct of the manu&cture of wood vinegar, and is thence obtamed 
by the jewellera and other workmen by whom it ia used in the 
arts. The charcoal produced in the distillation effected on 
Saturday, and which is permitted to cool slowly by remaining 
" in the retorts till Monday morning, answers the purpose of a sup- 
port in blowpipe operations much better than that which is 
drawn sooner from the retorts and cooled more rapidly in the 
open air. 

You prepare the charcoal tor use as follows : — 

Take sticks of an inch in diameter, or saw your charcoal, if it 
IS in thick masses, into sticks an inch square. The most convenient 
size tor the saw is one inch wide and nine inches long. My saw is 
a thin toothed fiat steel blade of that eiz^ without a hsadle. 



rsB or THB BLOwriPE. 123 

Next Baw these sticks croMwiae, into flat pieces one third of an 
inch thielc. The cut e represents the sarCace, and o e a section 
of one of the pieces thus produced. The radiating lines on 
^pire c, represent the crevioes in some sorts of charcoal. Such 
pieces are to be rejected as un6t for nse. Every one of these 
plates of charcoal must have a email circular carity on one side 




similar to that represented at d, m the upper figure, and at o in 
the section It must be the tinth of an inch deep, the fourth 
of an inch wide, and situate between the centre and the edge of 
one side of the plate of charcoal. This cavity is to serve as a 
species of capsule, to hold the substance that is to be heated 
fefore the blowpipe. The use of it is to prevent the matter 
from rolling off the charcoal, or from spreadin? too widely upon 
it, or from being blown away by the blast. To cat these cavi- 
ties yon must be provided with a charcoal borer, with which it 
is easy to sink a hole in the charcoal to any depth you require. 
This boiet is a conical tube of tin. plate, 2J inches long, a 



QZ 



quarter of an inch wide at one end, and half an inch wide at the 
other end. Both extremities are filed on the outside till cutting 
edges are produced. The larger end of this instrument is used 
to produce cavities to hold bone ashes when the operation of 
cnpellation is to be performed before the blowpipe. For an 
account of which operation, I refer you to the article "Analysda 
by the Blowpipe," 

The plates of charcoal, having been formed and bored, are to 
be brushed from loose dust by means of a tooth brush or nail 
brush, and to be preserved in a box for nse. You should never 
be without a supply. This method of making the charcoal into 
capsules for nse, is not only more economical than that of asing 
a urge lump of it as a support, but in all cases is much more 
cleanly ana convenient, and accompanied with far less risk of 
mixing and confuMng the subjects and products of diflerent ex- 
periments. 

l2 



JX 



f^ 



124 USE or THB BLDWFIFX. 

The charcoal capsules are too small to be held in the fire by 
the fingers. It ia necessary, therefore, to fix them on a support, 
the most conTenient material for which pur- „ ,, 

pose I find to be anarrow and very thin slip 
of tin plate, of the size and form shown by 
a&mthefigareonp.l23. The end of this slip 
is bent up into a sort of hook or clasp, a, e, 
and the plate of charcoal is pushed into the 
gap so formed. The tin piate most not be 
too thick, otherwise the elasticity of the bent 

part is not sufficient to 

secure the charcoal, nor 

its flexibility to enable 

it to suffer repeated 

bendings without break- 

mg. The cut m the 

margin exhibits the 

position in which the 

charcoal plate is expos- 
ed to the blowpipeflame. 

The end of the tin slip 
is held by the thumb and two first fingers 
of the leu hand, and the reijuisite steadiness 
is gained by resting the third tinger upon the 
semicircular projection, ij, on the left side of 
the lamp. 

PLiTiNrH Tongs. — The platinum tongs are 
nsed to hold small splinters of minerals which 
are to be exposed to the blowpipe flame, 
in order that it may be known whether 
they are fusible or infusible. The tongs are 
also used in other experiments that will be 
described .hereafter. The instrument is 
figured in the margin, both as seen in front 
and aside. The drawing shows the full size 
of the toDgs. n & are two plates of hard steel, 
rivetted together in the middle to a piece of 
iron, e e. The points, a a, are hardened, so 
as to act as nippers, and are used to ^lit 
small pieces from minerals for analysis. The 
points 6 b are rivetted to two sUps of platinum, 
which need to be rather thicker and wider 
at the end b than ia represented in the draw- 
ing. They taper off to a blunt point at c, 
not lareer than is here depicted. The small 
iron block, e «, is usually made slightly wedge-shaped, and 
should have been so represented in the figure with ita broad 
end towards a a. The object of this shape ia to produce a spring 
suf&cient to keep the points c c always shut when no other force 



USE or THs BLOwpiPB. 125 

ia in action. But to counteract this spiiug, and therefore to 
separate the points c c vbsa necessary, the steel blades are fui-- 
nished with two small knobs, d d, the pegs of which respectively, 
after passing through one of the steel olades, are fastened to the 
other. Hence when the finger and thumb are pleased upon the 
knobs d d, the platinum points c c separate, and when the pres- 
sure is removed, the points close and secure the object placed 
between them, in virtue of the spring produced by placing- the 
two blades a b aslant npon the wedge e e. This pattern of blow- 
pipe tongs is of French origin, and is much superior to all others 
that I have seen. It is the sort recommended hy Berzelius. 
The price of it is from 6a. to 7b. 

A Cheaper Variety <if Platinum ron^iismadeof two points of 
platinum of the size and thickness figured in the precedmg page, 
and prepared bv flattening platinum wire till it Becomes as tMn 
as a common playing card. These two points are rivetted to the 
two ends of an iron wire, the twelfth of an inch in thickness, 
and twelve inches long, bent into the form of a species of spring 
nippers. The inatrument should be five inches long when com- 

The blowpipe tonga made in London, are generally of a clumsy 
form, and by no means so handy as the French pattern, while 
they are Amy as dear. I have never met with any serviceable 
platinum tongs at a lower price than 6b. 

Platincm Foil. — I have described this support in the article 
oa "Sublimation," page 96. 

Platinum Wirb. — It ahould be of the length and thickness 
shown by the ioUowing figure. Such wires are sold in Olasgow 



for twopence. This wire is used when the subject of experi- 
ment is to be fused with borax, to ascertain what coloured bead 
it produces with that flux. One end of it is bent into a hook, 
OS represented above, or into a ring, as shown in the margin. 
In using thfe vrire you are to proceed as follows: — 

Moisten the hook with water or in your mouth, dip it into 
f\ the pounded borax, and hold it with the borax that chances 
to adhere, in the blowpipe flame, untQ the borax is fused 
to B clear and colourlesB bead, that fills the hook. Next 
moisten the substance to be heated, fix it to the bead, and 
melt the two together in the oxidating flame, sustaining a 
regular blast till the mixture is thoroughly melted^nd in- 
corporated, and there appears to be no further alteration 
produced by the flame. Thcfiised mass is, in this state, in a 
W)d condition for undergoing examination. You can observe it 
loth bv transmitted and reflected light, and without any of tho 
l3 

i,..ooglc 



126 DSB or THB BLOWPIPB. 

danger of mistAke which arises &om the play of folfie colour^ 
that is so liable to perplex you when examiitipg a coloiued glass 
Qpou cbaiixiBl. 

The gl^as bead, thus melted into the hook of the platinum 
wire, must, after examination, be removed, to permit the clean- 
ing of the wire for a new experiment. If you attempt this re- 
moval by crushing the bead with the stroke of a hammer, you 
will often find the glass to be hard enough to cut the wire. It 
ia better therefore to soak the bead in water, or in rery dilute 
muriatic acid, and then to wash out the flux. This however 
requires time, and it becomes on this account neceaaary for you 
to provide yourself with two or three of these wires, that you 
may always have one in a fit state for use. If you should acci- 
dentally ruse on the wire, tin, lead, or any other substance capa- 
ble of attacking it, a list of which substances I shall give under 
'' the head of " Platinum," there is no remedy but to cut off the 
end of the wire and bend a new hook. Accidents of this kftid 
sometimes occur to the most cautious, and thus the wire is gra- 
dually shortened. When it is reduced to about an mcfa in 
length, and can no longer be held by the fingere, the point of 
it ^ould be melted into the end of a piece of thermometer tube, 
which then serves as a handle, and enables you to use it till 
almost entirely exhausted. Even a bit of cork ia sometimes 
use&l as a handle for a short wire. 

Copper Wire, — A very fine copper, or brass wire, of the fol- 
lowing shape, is used in the blowpipe experiment for the detec- 



tion of chlorine and iodine. I shall have occasion to speak fiilly 
of this wire in the article on " Analysis by the Blowpipe." 

There are no other means of supporting object* in the blow- 
pipe flame which are of sufficient unportance to demand any 
particular description. 

THE FLUXES USED WITH THE BLOWPIPE. 
The most important of the chemical compounds which are em- 
ployed to faralitate the fusion, or to effect the decomposition, of 
substances heated before the blowpipe, ate these three;— 

1. Borax, 

2. Carbonate of Soda, 

3. MicBocosiiiic Salt. 

The chemical history of these substances, and the methods of 
prepaifcg them, wili be found in the article " Sodium," The 
mode of using them as fluxes in blowpipe operations, will be 
found in the article on " Analysis by the Blowpipe." 

Chemical Preparations required in a few peculiar Blowpipe 
ExPEBiMBNis. — These are offer less generalvte thim the fluxes 



nSB or THE BLOWPIPE. 127 

named above, but are, nevertheless, necessary to have at hand, 
to aid ui the detection of particular eleinenta. 

1. Saltpelro, in ranill long crystals 

8. Biaulphite of Potish, fused and powdered 

3. Gypsum, water free, in small grains 

4. Fluorspar, irater free, in small grains 

6. Nitrate ot Cobalt, a strong solution in water 
6. Oxalate ofNieke), in ponder 

T. Tin fail, cut into slips half an inch wide, and roUed hard up into 
little rods 

8. Lead, in lin« grains for cupellatio^ 

9. Bone ashes, for cupellation 

10. Silica, in line powder 

11. Test papera in narrow slipa 

12. Formate of Soda. 

The whole of these testa are, of coarse, to be provided in a state 
of purity. The method of using them I shall describe in fmeak- 
ing of the substances which they arc employed to detect, m the 
article on " Anaiysis by the Blowpipe." 

BOXES TO HOLD THE FLUXES. 
In operating with the blowpipe, it is necessary to have always 
close at hand the various fluxes and tests enumerated in the 
preceding section, as weU those required for particular opera- 
tions as uiose of more general utility. When you begin to exa- 
1 unknown substance, it is impossible to foresee v'--' 



youi first experiments m^ indicate, and what particular mode 
of treatment you may be forced to adopt subsequently. Henoe, 
it is proper to have ready for use whatever is likely to be in re- 
quest, and as the substaocca employed in operations of this de- 
scription are but few in number, and not of great bulk, it is 
easy to arrange the whole of them in a very small box. That 
which is exhibited in the following figure was contrived for this 
purpose by Oahn, and is now recommended by Berzkhus, It 




is a wooden box, 8} inches long, 1^ inch wide, and 1 inch deep. 
It contains 9 square cells, each provided with a separate cover, 
and the whole surmounted with a common cover, which can be 
secured, when closed, by a pair of hooks. The large cover is 
provided with brass hinges, but the small covers have wooden 

, .. Cooglc 



128 UBK or JHE BLOWPIPE. 

hinges gimilar to ihose of ttie Scotch Banff boxes. AIL the covera 
require to be made ao aa to fit close and prevent the eacape of 
the powders that bj« to be kept in them. 

In Bome boxes the eKpense of these wooden hinges is obviated 
by the use of a fold of leather as a hinge. 

Each re-t^nt that is much in use has a box to itself but 
those wliich are used only in particular cases, are endoeed in 
paper, or small pill boxes, or short gloea tubes, and packed 
several together la the reminder of the boxes. The boxra are 
sometimes stamped in &ont or on the lid with the names of the 
substances within them — as, borax — soda — hic-balt — &c. The 
price of such a box, of polished wood, is in Glasgow, 12s. 

SErernoEH has contrived a box of another kind for the travel- 
ling students of the School of Mines in Fohlun. This conusta 
of a aeries of short bottles with wide mouths (such as Preston- 
salts bottles), closed with corks, each bottle and cork being 
labelled to correspond. As many bottles are provided as there 
are dirisions in Oahn's box, and they are fitted stiffly into a box 
of japanned tin plate, which is made long and narrow to hold 
them in one row. The heiebt of the sides of it is two-thirds 
the height of the bottles. The cover is in a separate piece, not 
fastened with hinges, but made to slip on like the cover of a 
tobacco box. 

The veesols in which I keep the fluxes for my experiments, 
are small #nt# boxe^ about 1^ mches long, and ^inch deep, some 
of them made of wood, and others of papier machee. The covers 
are fastened on with tunges, they readily open and stand open. 
The names of tiie fluxes are writton or painted on the top of 
each box. Being small and £at, tikey are easily ranged in any 
order 1 wish to put them. A few articles I keep in pill boxes 
and glass tubes, all labelled. 

MISCELLANEOUS APPARATUS 
Employed in Blowpipe Operations. 

I. Hammer S. Flat blla 9. Wubing Bottle 

8. Anvil 6. Agate MorUr 10. LudfcT lUaichts 

3. Knifo 7. A^roacope II. Small Porcftain Capiules 

i. Three-edged BI« B. A "I^y 1!. Small Platinum NpHlula. 

TiiK hammer and anvil are for striking off bits of minerals for 
anaIysls,or fortestingthemalleability,&c. ofmetols. Theknife 
is for mixing fluxes with powders preparatory to an operation. 
The mixture is kneaded in the palm of the len hand. A plati- 
num spatula answers this purpose better than a kniie. The 
latter, however, serves also to test the hardness of minerals. The 
three edged file is to cut glass tubes, Or to try the hardness of 
minerals. The flat file is to file corks into shape, and sometimes 
to file metals. The agate mortar is to pulverise hard substances 
that require to be mingled and fused with fluxes. It is also in- 



USB OP TBG BLOWPIPE. ' 139 

diEpensable to the auccess of the operation of TednciDg metallic 
oxides by means of soda. The microscope ia to examine the 
resnlta of experiments. It should be a single lens with strong 
magnifying power. The tray is to put below the lamp when you 
are working. The stone ware tray described in the section 
"laboratory," answers the purpose very well. The bottom 
should be covered with a sheet of white paper, and it should be 
cleaned after eTery experiment. Its use is to catch and preserve 
ki a clean state, tne substance under examination, whenever it 
accidentally fells from the support, A tin tray, a sheet of paste 
board, or alai«e dish, serves the same use, Lucifeis are to pro- 
vide a light when necessary. The small porcelain capsules are 
useful to hold the substances that are prepared for examination. 
Sometimes they serve to evaporate small quantities of solutions 

5roduced in operations where acids are called in to aid the 
lowpipe. 
Most of this miscellaneous apparatus is so fully described in 
other sections of this work, that it is unnecessary to dwell upon 
it in this place. 

PROPER SIZE OP THE ASSAY. 

The morsel submitted to experiment, is large enough when you 
can distinctly see the effect produced upon it. If the piece ia 
too large, a part of it is necessarily out of the focus of the flame 
which is but a small point, and must then tend to cool not only 
the support, but the part of the assay which is immersed in the 
blue apex of the flame. The consequence of (hia is, that the 
heat is carried off as fast as it ia produced,*and you exhaust 
yourself before you effect the assay. You are much more likely 
m all cases, to Ml in your experiment by using too large rather 
ttum too small a piece. The size generally recommended in 
books, 19 that of a pea, a pepper corn, a cube of the eighth of an 
inch, &c, is many times too large, A piece of the size of a grain 
of muatard seed la almost always sufficient, A small piece shows 
the same characters as a large piece, and an experiment upon it 

. is made in less time, and with less feti(fhe. The size of a bead 
of borax or of microscopic salt ahoul^be this— O, The size of 

' the mineral particle added to such a bead, should not exceed 
this — 0. 

A PROPER TABLE TO WORK AT. 

The instruments used with the blowpipe ought to be so arrai^d 
as to be always at hand when required^-all provided with places 
into which they can be readily put, and from which they can be 

{romptly lifted; I shall describe the work table recommended 
y GiHN «id Behzklius. The form of it is exhibited by the 
cut in Uie following page : — 



F THE BLOWPIFB. 



At each of the two ends there is a drawer, or tray, which can 
be pulled out, as ia represented in the figure, so as to display 
its whole contents at once. These drawers are prevented &om 
falling by fistuie fiUets of wood that run in grooves under the 
table top. The blowpipe apparatus and fluxes are arrauged in 
these trays, the articles that are most frequently requirrf 
being put into the right hand tray, and the other articles into 
the tray on the left hand. The cUvisiona in the traya, as shown 
in the figure, are not fixtures, but consist of small boxes of 
tin plate, which are eawer arranged, and are easier ako to keep 
clean, than are cells made by fixed partitions. 

The four drawers in front of the table are used to hold the 
lamp, the tin tray, a supply of charcoal, stock of fluxes, lamp 
wicka, subatanccB intended for examination, and other bulky 
artidea. A towel, often required in the course of working wiUi 
the blowpipe, ia hung to a email hook below the table, near to 
the operator's right hand. 

Those who cannot get a table of the abore description, or 
cannot provide a aituation for auch a table, may keep their ap- 

faratuB for the blowpipe in a work box. This is the plan which 
have followed ibr some time, and find to be convenient. 
The box may be made of mahogany, or japanned tin plate. 
It should be eleven inches lone;, nine Inches broad, and four 
inches deep. The cover should lift on and ofl', and be without 
hingea. There should be two trays exactly large enough to fit 
the hox, yet so as to be easily put in or pulled out. They should 
both be an inch deep on the outside. Several small boxes, two 
inches deep on the outside, should be put into the bottom of 
the box. The two trays rest upon these boxes, and fill the 
large box ta the top. The small deep boxes serve to hold the 
lamp, charcoal, supply of tubes, and all the larger articles. The 



r THS BLOWFiPB. 131 

two npper trays are divided so aa to hold all the small articles; 
the blowpipe, the three fiuxta, the platinum supports, and the 
articles most frequently wanted being arranged in one tray, and 
the residue being packed into the second tray. Durii^ an ex- 
periment, the top of the box, inrcrted, supplies the place of the 
tin tray spoken of among the miscellaneous apparatus, — the box 
should be placed in front of the operator, the tray with the 
blowpipe on the right of the box, and the other fray on the 
Opposite side. The whole laboratory is thus laid open. 

I p^ now to the inlorpretation of the effects produced by 
blowpipe e^ierimenta. 



( 

ANALYSIS BY THE BLOWPIPE. 

fW the routine of Qualitatire Analysis, the Blowpipe is ex- 
tremely oseiiil ; for it resolvea, with ease and precision, doubts 
respecting the presence of particulai elements, which could only 
be otherwise determined by a tedioos couise of operations. It is 
impossible, however, except in the case of substances that have 
Tery few constituents, to effect qualitative analysis by the blow- 
pipe alone. It must always be taken as subordinate or prelimi- 
nary to liquid testing, or be excluaiTely applied to use, only 
when presenting facilities where liquid testing is not convenient. 
This faciUty of experimenting occurs, for example, in travelling, 
and now and then in chemi^ manufactories, where a question 
which has often to be decided is whether— «inong a variety of 
indifferent matters — some one us^I, or at any rate, intereiting 
substance is, or is not, to be found ? This is a point which the 
blowpipe can often settle readier than any thing else. In such 
cases, therefore, this instrument comes into requisition. 

The blowjiipe experiments that give useful resulta, I shall 
here throw mto aucn a routine qf operatum^ as appeus to be 
best adapted to the detection of aB the constituents of an un- 
known substance, when liquid testing is to be dispensed with, 
and the blovipipe to be used ato«e. But I do so without intend- 
ing the pyrognostic assay to be held as any thing more than a 
couiSe 01 experiments preparatoiy to liquid testing. 

This nratme is as follows : — 

Jst, The substance is heated in a amaQ glass tube closed at 

2ndly, It is heated before the blowpipe in the open ait. 
Srdly, It is heated in a glass tube open at both ends. 
4tlily, It is heated with caxhonBXe of soda. 
Sthly, It is fused with mioocofflnic salt. 
ethfyy It is foaed with borax. 



IlLFSIB BT THE BLOWFIPB. 
>henoniena exhibited by a eubstBiii 



e on eTOOBure to 
chemical nature. 



FIBST OPERATION. 



SIethod. — The managemeiit of this operation has been de- 
scribed in the article ott "Sublimation," page 103. 

Object of the Operation, — To ascertain what change is ef- 
fected in the appearance of the substance ; what sort of matter 
is disengaged— whether gaa, liquid, or solid sublimate ; whether 
or not decrepitation or phosphorescence takes place ; whether . 
the volatile products are acid, alcalinc, or neutral. 

If the substance chars or turns black, it nrny be presumed to 
contain vegetable or animal matter. If liquid is condensed OQ - 
the upper part of the tube, the substatice may be a hydrate or a 
salt with excess of volatile acid. If a powder appears on the 
side of the tube, it indicates the presence of volatile metals or 
oxides, or of sulphur or selenium. The metals are at once dis- 
tinguished by their lustre; the other substances can be discrimi- 
nated by their particular characters, as I shall show presently. 
The following is a list of substances that can be volatilised by 
this method. 

A, Organic Bodies. 

B, Water. 

C, Volatile Acids, gaseous and liquid. 

D, Sulphur. 
£, Selenium. 

F, Volatile Metals. 

O, Volatile Oxides and Acids, of a soUd form. 

H, Volatile Saline bodies. 
The characters of these substances I shall give individually, 
commencing by explaining more fully the inferences to be 
drawn upon seeing the subject of experiment become black when 
heated. 

A, ORGANIC BODIES. 
The first operation serves very well to indicate the presence 
of organic eub»tancet, when constitutuig or contained in the 
object of experiment, almost all of which substances, when 
heated in tlus manner, suffer decomposition, give off copious 
vapours, (md leave a fixed redduum of charcoal. The volatile 
matters given off are water, acetic, and various other acids, em- 
pyrenmatic oU, ammonia, carbonic acid, sometimes cyanc^en, 
and other compounds, according to the nature of the particular 
organic body submitted to examination. But it is to the pro- 
duction in this experiment of charcoal, as serving to discriminate 
organic from inorganic bodies, that I am desirous of directing 



DETKCTIOM OF ORSANIC BODIBB. 133 



your chief attention. The discriniination of o^snic robstancea 
from one another, is no part of the businesB now under con- 
sideration.'' *• 

Many iDoi^anic bodies also become black when heated in a 
glasB tube, either in consequence of containing a slight intermix- 
ture of organic matter, or irom some other accidental cause. 
The difference in appearance, however, between a blackened 
inorganic body, and a charred organic body, is rery consider- 
able; as, in case of doubt, yon can prove comparatively by ig- 
niting a small portion of any organic substance in a Beparat« 
tabe. If, however, a comparative experiment of this kind does 
not satisfy you, the following more conclusive trial may be 
made: — MeH a little nitrate of potash in a porcelmn cup over 
the spirit lamp, and throw a little of the unknown substance 
into tne melted salt. Every organic substance, or nearly so, 
deflagrates when thus brought into contact with ignited salt- 
petre; and though some inorganic substances, such as sulphur 
and the sulphurets, do the same, yet carbonisation by heat, and 
deflagration with saltpetre, are characters that when taken 
together evidently denote an organic body.^ If organic matter 
is found to be present in a state of admixture with the snbstance 
. to be examined, it is advisable to get rid of the organic matter 
by combustion, before proceeding farther with the analysis; for 
the action of liquid tests on inorganic substances is materially 
altered by the presence of organic substances. With a view to 
effect this object, a small portion of the compound ia first to be 
heated on chareoai beibre the blowpipe, in a manner to be here- 
after described. The purpose of this preliminary experiment is 
to ascert^ if the snbstance conttuns a metal eaaly reducible 
when heated with charcoaL If it does not, a portion of the 




. % imrgt «ade bj meltings n qoanm^ ot 
qd potuiuff bil 

LUprodiuednhaiDrgHjlcbodletj 
Uk« ihircoil, irhen Chnnrn Into red ha[ Ditn. 



134 AKALTSia BT THE BLOWPin.— OMRATION I. 

substance may then be ignited in b Hmall platinum cmdble over 
the lurge Bpint lamp, ^e crucible is to be placed in a sloping 
position, the cover about three-fourths on, and a slip of iron is 
to be placed on the open part of the crucible, to produce ^thin 
it a cnrrent of air. See paM 101. The organic matter is tbos 
both charred and ooneumeo. If^ hoTerer, the experiment on 
charcoal shows that easilj reducible metals are present, tli«i 
the platinum crucible cannot be used, and one of porcelain must 
be employed in ita stead; but in this case the conversion of the 
chured organic matter into carbonic acid does not succeed 
nearly so well as it does in a platinum TcsseL 

B, WATER. 
iTmay be present as combined water, (a only held mechani- 
cally. The former is found in hydrates, erystalliEed saltB, &o. 
The latter occurs in salts that decrepitate, and in all porons 
bodies. The water raised firom thcM bodies in rapour, settles 
upon the sides of the upper part of the tube. If the quantity is 
considerable, it is held to be an essential constituent of the anb- 
stonce operated upon. While the tube is hot, it must be held 
in a poaition nearly horisontal, or rather with the mouth inclined 
downwards, lest the water run back to the hot part of the tube 
and crack it You try, with test p^er, whether the water is 
neutral, acid, or alcaline. The latter indicates the presence of 
ammonia. The tube sboold be wanned and dried immediately 
before the experiment.*- *■ '■ 

C, VOLATILE ACID8, Gateout or Liquid. 
Super Salts, containing acids that are volatile, either when 
pure or when combined with water, give ofF, on being heated 
m this manner, their excess of acid; and if raoistenc^ litmus 
ito the nei^ of the tube, it becomes 
f the neutral salts of these volatile 
acids are decomposed by this procesi. This is particularly 
the case with many Nitrates, the presence of which is indicated 
fay the production of copious red fumes of nitrous acid gas.^ 
llie Hypomlf^tet also are decomposed, and give off sulphurous 
acid gas. And such Fluoride* as contain wat^, are decomposed, 

WMaron ths 

^■v. Teat with Utaoi pftper, mAd fldd Uh wmt«r luaai]. 
C. RfliwM the exiHrimept with » mull pl«De rtf hydrout gj^ifon. 
a R^(MttirlthallttlaerTrtsUlnilnil|diUtDrHda,Drg>rboBitei>fiDdit. 
t. Hot ■ Hcill qouUtr of itj Wndphate dT potmb tn ■ dowd tuba. Inert m 
■Up otbhie Utmu faper. Otnerre ttiH it beconei reddened. 

S. HotBUttlanttnte Mind !■> eloKd tube, Oteerre the nofaittOB oT nd 

fiUBM ot BltTOBi hU KU, IndSrmtlnR tlis dHompdritlDB of m nitnla. 

Kepe«tliee»pertiii«l with nlinit»of i»)i«h, OTwrro tbe fntlon rf «* "H 

' <n>H|nenOy wltlKiDl ernlntlmi of the red Aine*. It 

' ^' efl Df the alfallfli tku tbuB? 



DXTXcnoN or BOLPHUunra. 135 

and gwe off hydrofluoric add. This acid turns motstened brazil 
trood teat paper yellow; but the experjmeut reqniKS a strong 
red heat, and a hard glass tube. 

Oxalic acid in a tree state volatilises undeoompoaed; but the 
oxalatas of fixed alcalies and of eartha, give off carbonic oxide 
gas which can be ignited at the mouth of the tube, where it buma 
with a blue flame. Other oxalates give off carbonic acid gas, 
some with admixture of carbonic oxide gaa. The fixed catbonote 
which remains behind is generally blackened by adhering char- 
coal. The Cyanides commonly are strongly charred, and dis- 
engage nitrogen gas, often accompanied by cyanogen, ammonia, 
and water. Dry cyanides of the metals of the alcalies and the 
earths are not decomposed by this proceae. Dry cyanide of 
sOver or of mercury producea cyanogen gas and metal. The gaa 
can be burned at the mouth of the tube, where it producea a 
blue flame. 

D, SULPHUR. 

BuLPHUR can be snblimed either fit>m asubstance contain!]^ it 
in mechanical admixture, or from such metallic sulphurets as 
snffer a partial desulphuration when exposed to heat in close 
ressels. Such are the higher sulphurets of iron ^pyrites), cop- 
per, tin (aurum muaivum), and antimony. Some other sulphurets 
give oET small portions of sulphur, in consequence of a partial 
oxidation of their metallic base effected during the operation. 
The solphur sublimes in drops, which ore reddish-brown while 
hot, ana yellow when cold. The hypoaulpliites also sublime 

Only the volatile metals produce volatile tulfAvreti, and only 
the smphurets of mercury and arsenic sublime undecomposea. 
The BUDlimate of the former ia black, but becomes red if rubbed ;'<* 
that of the latter is dark-yellow or red.''- ^- But the solphuret of 
arsenic is apt to be mistucen for sulphur, and ita diacnmjnation 
requires a different experiment. See " Arsenic." 

9. Fat k uuU quutit; of iDlphiir hitn ■ cloud tatw. nod laULma It by Ui* host ot 
tliB spirit luDp. Obterve tha appeiniQcos producfrd, the odour, and tiie mctJon of 
Iht vapour upon bluo Utmai paper, that you maf b« prspared to neognUe lul^hur 
what rou aft^rwardH sabUino it from an unknown tabtCani-fi. 

10. Hntalitllaiulpburatvrniercarf inadoied tDbe. Voa wUl produce a lab. 
Umata. Uthc tube ki Fn]riiiiall,lbe lubUmate will brbUckBulphuntoriBaKury. 
irthetubelitowids at to admit Iha rirenlatioa of atmogplieric sir,* partial ds. 
compoiltioo 1b elTHtod. and tbo iaUlmate li pvUr black Bul[Aiiirot; a4d partlir 
meiallic vnercorr. Scmlcta out a Utile of t^fl black lulpliuret upoa paper. Uub it. 

11. Heat B little realgar ia a cloMd tulw. Obeerin clie fnaloa and boding, and 
tli«D Ibe farmatioa uf a luhlimace Id the fonn of crimioa dropa, wbloh look like 

la Hsat orvlment in tfes ume DBDoer. ObMrrathil thaiabUiDateliiiipoiTder, 
part lit it banog a red-brown colour, and pert at ll a clasr yellov colour, liaiilar 
to the coliiur of pura lulphor. 



136 ANALYSIS BT THB BLOVPtPK. OFBIUTIOK I. 

E, SELENIUM. 
Selenium can he sublimed under the eame circmnstaQces as sul- 
phur, either when present in admixture, or when contained in a 
state of BUperabondance in Beleninreta. The sublimate, if small, 
is reddish, if large, it is black. If heated strongly in the open 
air, it produces b, strong odour of decayed horse radifdi. 

F, VOLATILE METAI5. 
TiiEra are arsenic, mercury, cadmium, and teUurium, which 
all possess metallic lustre, and a black or grey ctJour. 

1. Artenic. — It sublimes eitherfrom metaUic arsenic, or &om 
certain alloys of arsenic — each, namely, as contain a large pro- 
portion of arsenic, and are reducible by heat into alloys with a 
smaller proportion, and secondly, such aa contain Brsenic in a 
feeble state of combination. To the first variety belong arsenical 
nickel, arsenical cobalt, arsenical iron;'^ '*' to the latter belong 
the combinations of ars^iic with antimony. A sublimate of 
arsenic is also given by some of the arserutfls. The cbaracteri^ic 
of anenic in the state of vapour is its smell of garlic. 

2. Ma-eury. — It is sublimed Irom most of ite compounds and 
is more easily detected than any other metal. If the quantity 
of the sublimate is small, it has a grey earthy ai^earance ; hut ' 
friction with a glass rod unites the ininnte metallic particles into 
visible drops.'' 

3. Cadmium. — It is sublimed from some of its Etlloys. It is 
distinguished from other volatile metala by producing a yettow- 
Uh brovm ntbUmaU of oxide of cadmium when heated upon char- 
coal in the open air: the sublimate falls on the charcoal wound 
the assay. 

4. TeUuHum. — It is rather difficult of sublimation, and when 
the experiment is made in a ^all closed tube, the sublimate is 
only produced at a very strong red heat. It is depoated in small 
metallic dropson the cold part of the glass. The drops resemble 
those of mercury, but are solid. 

13. H«t > utile Bdiplclitl (wtcnkil km) in ■ tube nt YnaA gimu mde wilknut 
iMd, Inovmw Ow bMt gndaillr, it lut nmldn; it prstlr Hmng. Hnt, you 
will obtern t, red mbUiiwIe, which li gulptiorst at •twdIc. Aftermrdi joa will 
Ke meMlUe uwnic on the lobe. When yau do te« It, hHt the part ol the tidie 

tlio llib# nou yonr nose, uid imeU the odour i>f fvlic hy which the vapoor of tX- 
■enlc ia r*t-ofiiiud. Eemember that tJila nponr Ih pi^BODoaft, and that it It not Co 

14. Bepeatthe experiment In the nnn^legl luha thu you cm procure, la ucertaJn 
upon vhat email r)niintitie9 of anenlcal egirpnundi it ii pouihle to work, wilhout 
■acrllclnf teanatj In the malu. 

15. HeU Terr email iinantiUea of red oilde or inercarTioraryiuiTOWHidEhort 
glau tobea cloied M ooe end. Devompoiition ipewUlir laliei place. Oxygen gaa 
la expelled, and metallic mercur; labllmed, Uie at Snt one gr^ o( the rad oxide. 
Then repeat the experiment with imallar quanttdei, ai with the half, fourth, 
tenth of a pTin, and bo on, in order la ■srertwn what la Iha nniilleu qiiantitl with 
which joa ^Q oiit^n a utisfoctory reenit 



DSTZCTIOM O* VOLATILB 8ALTI, 137 

a, SOLID VOLATILE OXIDES AND ACIDS. 

These are oxide of antimouv, oxide of telluritun, arsenifnia 
acid, arsenic acid, and oanuc acia. 

1. Omde of Antijnonj/ first fuses to a yellow liquid, and then 
sublimes in shining needles. AntimoniouB acid, which is often 
present in oxide of antimony, does not sublime. 

2. Oxide of Tellurium behaves nearly like ojdde of antimony, 
but does not give a cryetaltins sublimate. 

3. ^^-seniofw^cui sublimes very easily." The sublimate con- 
sists of microscopic octahedral crystals. See the general article 
" Araenic." 

4. Araenic Acid is decomposed by a strong heat, givea off 
oxygen gas, and produces a sublimate of arsenious acid. 

5. Ogmic Acid sublimes in white drops and forms crystal 
needles on the cold part of the glass. It has a strong and pecu- 
liar odoDT and acts upon the eyes. 

H, VOLATILE SALINE BODIES. 

Thbsb are the salta oi ammonia, and the chlorides, iodides, 
and bromides of mercu^. 

Ammoniacai Saltt. — They all sablime without reaidue, unless 
they contain a fixed acid, such, as the phosphoric, or the boraeic 
acid. They are then decomposed, and the acid remains behind. 
The disengaged ammonia is detected by its smell, or by its alca- 
liue action on turmeric paper, or reddened litmus paper, placed 
in the tube. 

The simplest way to test these salts, is to mix them on plati- 
num Ibil, or in a small cup, with a little carbonate of soda and 
water, and to apply heat, whereupon ammonia is disengaged in 
abundance.'' 

Perchloride of Mercury (corroHve tvblimaie) at a very gentle 
heat, first liises and then sublimes. 

ProtodUoride of Mercury ( Oalomtl. ) — Sublimes without fuang. 
Its sublimate is yellowish while hot, but white when cold." 

Bromide) and Iodides of mercury behave much like the chlo- 
rides. It merits remark, however, that the red iodide gives a 
yellow Hubbjnate. 

Such are the characters of the substances that can be volatil- 
ized by simple ignition. 




138 AKALTBIS BT THX BLOWPIPB.— OPBRATIOM I. 

The closed tn.be is also employed for the ignition of mbstances 
that derrepUaU^ and the wanning of euch as phoaplioretee. The 
mineral called flaorapar exhibit!) both phenomena.)^ ^' 

VARIATIONS OF THE FIRST OPERATION. 
A VARiETT of snbatances are heated in the closed tabe in admix- 
ture with re-^ents, which effect changea that heat alone is in- 
Buflicient to effect. Thna : — 

A, Merctuy is detected by dried soda, by a method to be de- 

scribed presently. .( 

B, Nitrates "J 

D Sm^^ C ^ detected by bisulphate of potash. 

eI Bromides J 

F, Sulphates of the common Metals, by charcoal powder. 

A. Mercdht. — Both of the chlorides, and indeed all the com- 
pounds of mercury, if mixed with dried earbonale of »oda, and 
heated in a closed tube, rive a sublimate of metallic mercury. . 
Whenever, therefore, a substance ia suspected to contain mer-„_ 
cury, it is mixed with an exceaa of soda, previooaly dried by .■'■ 
ignition in a platinum spoon, or in a Hmall porcel^n cnp, and 
the mixture, mserted in a tube, is heated, first by the mere flame 
of the spirit lamp, and then by the same flame urged with the 
blowpipe. If mercury is present, a grey coat of sublimed metal 
soon appears on the cold part of the tube. It sometimes, how- 
ever, does not resemble metallic mercury, bnt the minute drops 
of metal can be eamly collected into visible globules by friction 
with a glass rod or a bit of stick. If the compound contains 
water, or if undrUd soda is used, then water as well as mercury 
Gublimes, and the water, readily forming into drops, is apt to 
run down to the hot part of the tube and crack it. To prevent 
this, the tube should be held as much as possible out of tne per- 
pendicular, or the water may be abstracted from the tube by 
msertmg into it a small roll of blotting paper. 

If the subject of experiment be extremely volatile, such as 
the chloride or bromide of mercury, it is possible to manage so 
ill as to drive ofi^ the whole of it io vapour before raisinff a 
Buffident heat to enable the soda to decompose it. In such a 
case no metallic mercury is got. This efiect can be prevented 
by mixing the compound and the soda with water, and applying 
the heat pretty strong at first. You run the risk, however, of 
breaking the glass by this procedure. 

IS. Take ■ Mt of flasnpu- tbDnt hiilf th« >in of ■ p», ond hint it fo ■ glua tiilH 
hiTlngm bulb UU>8 end. A Tcr; nniill Una nunr ingwcn hmt. Tl» wlrkoftbe 
spirit luop iluHild be puhed Blnootl cIdm into the tube. A srmt nuiDT nrieUoof 
Aaonptr. bat not nil, gire, when that beUad, > pale purple Umbent Ugbt, ^milw 
tn that nObided b)r tbe tlow ipoiiUneoDi comboitlnn of phoapLnnu. UpoD nltbig 
ilka heU, drrrepltalioii «iiu«. 

». CMBBOa Hh trBot«l in tbe time minner decreiillstei, bot iloei not phMphor- 



DISCKHftHATION OT BALTS. 139 

Another usefiil metliod of operating is to iiBe a rety narrow 
f^asH tube, to pat the mercnriAl compound at the bottom, to put 
above it nearly an inch of dried carbonate of Boda, to make the 
Boda red bot by holding the tube horizontally across the spirit 
flame without heating the mercorial compound, and finally, 
when the soda is red not, to incline the tube ia such a manner 
as to bring the point of it where tbe mercurial compound is 
placed into the spirit flame without withdrawing the portion 
that contains the soda. The mercurial compound then sublimes 
through the red hot soda and becomes decomposed. ^'' ^• 

B, NiTRATSs. — When mingled with pounded bisulphate of 
potash, pat into a glass tube, and heated in the flame of a spirit 
lamp, the nitrates disengage abundant vapoura of nitrons acid. 
This is readily distinguidied by its strong led colour and pecu- 
liar odour.'^ 

C, Fluouoes. — When mixed and ignited in a dosed tube with 
bisulphate of potash, the flnorides disengage hydrofluoric acid, 
which corrodes the neck of the tube and makes it opaque, and 
changes red brazil wood paper to yellow. The tube requires to 
be cleaned befbre its loss oi^ transparency can be ascertained.^ 

D, Iodides. — When mixed and heated with bisulphato of pot* , 
ash, the iodides disengage iodine in vapour. Its violet colour is 
readily seen. It condenses into a black sublimate of iodine, and 
sulphurous acid escapes from the tube.^^ 

E, BaouiDEs. — When heated with bisulphate of potwih, the 
bromides disengage sulphurous acid gas, and a little bromine gas, 
the colour of which is yellow ; but it is only a little, and the ex- 
periment is scarcely to be d^ended upon as sufficient to deter- 
mine the prffleoee of bromine. The tnal must be made by day- 
light. 

F, Sulphates. — Ignite the powdered sulphate in a silver or pla- 
tintdn spoon in order to drive off wat«r! mix it with dry (ignited) 
charcoal powder, and ignite the mixture in a glass tube, nmng 
the blowpipe to strengtaen the flame. There will be a strong 

*1. Biuolna »pn1maili11r Oiac thm methodi. TikstkrH imn tabs and 
> quartAf of m gnia of cormiTfl nibltmvte to «kcb. Ia tbe flnt. mix HDd heMt tb« 
Denurtail tilt wJtIi drjartwDite oT aodii! In the vxooS. iHth wet culKHiAtfl of 
■odA; in tbt lUrd. hrmt II wiEh dr^ Boda pUc«d vbova it and Ignited yrarioualf, 
Mml pnMdf , in an ca<i»> jau will obt^n aiubUmMe composed pvitir ormetallio 
mprcury aiid partly of a white povder, Fon&lEtiiii- of nDdeconipaHd forroBiTe lab- 
limale. Tbpm«t BucfuifulexpeiiiDsnt b tlutwhlcli affords tbe tcreatot qaimtitj 



li. Aftli 


r>rardMnkBaIi 


Itia natlFC d 




'.ororfRcUtiiHiiialphiirei 


t at ner- 


,orf,orrf 




iDsta] ; ndi it with 




ofMdmand 


ignllell 


il>.arT„ 


»ll<^)«>dKl>» 


tube. Ob«r 


• a tbe 


•BbUniationafBel^eiH 


mm- 


58. M.11. 


IgTmlnofnltrewithagnlnot 


blmlphateofpotmiA, 


■nd beat tbe 


mlitore 


matiBiUc 


il«edgto-tub« 


. ObwrraU. 


sredl 


'ome, of nitron 


..«ad. 




M Ifnlta poundfd flnon 


ipmi witb U>u 


Iphate of potaib, and 


ObHTVStlH 




ofhTdrBau' 




'a«, and npo. 










S6. Mill 


tgT.li. of Iodide 
I In ■ tmall clDM 


oTlpadwItbt 
^Euba. Tbe 


: .pi™ 


uD.arbl.ulpb> 


ta of poUih, 
gur of lodlni 


andbaat 


tbe millori 


did purpl. ».p 


ilt.wa 

















140 ANAITSIB BT TH» BLOWMM, OFKRATION I. 

disengagement of nilphuroiiB acid, which is rsadily known by 
its odour, and by its ability to bleach moistened Brazil wood 
paper. This method of detecting solphatea applies, however, 
only to sutphatea t^f redvdbk metalt, and not to such aa con- 
tain eartlis or slcalies.'^ '?' 

Arbbnio. — It is by operations similar to those we are consider- 
ing, that arsenic, in its metallic state, is frequently reduced from 
TCry small portions of arsenical compounds obtamed in medico- 
legal inveBtigatbns. Thissubject, however, will be fully treated 
of under the general head of " Arsenic." 

RSDVOnONS BFFEOTBD IH ClOSED HvBtB BT UBANB OT FORMITB 

OF Soda. — ^When formate of soda is ignited, it gives off a large 
qnaotity of carbonic oxide gas. If the formate of soda, previous 
to its ignition, is mixed with a met^lic oxide, or if the nascent 
carbonic oxide gas is passed over an ignited metallic oxide, it 
in either ease effecla a ready reduction m the metal. 

Artenic. — Mix half a grsin of an arsenical compound with 
twice as mnch dry formate of soda. Insert the mixture (pi^ 
105) into a glass tube, one-tenth of an inch wide, and two inches 
long, and expose it to the heat of the qiMt lamp as shown by 
the figure at pf^ SB. In lees than a minute, the experiment 
is ended, and metallic arsenic in the form of a sublimate appears 
at a httle distance from the end of the tube. The hundredth of 
a grun of sulphuret of arsenic, or of an araenite, or an acseniate 
can, according to Goebel, be thus reduced. When a metallic 
aisenite is thus decompoeed, the base U also reduced, and upon 
washing the remdue in an ^ate mortar to separate the soda, (see 
the reducing operation with soda) the metal is obtained in films. 
In case of admixture with sulphuret of antimony, a thousandth 
part of arsenic can be thus detected. Hence this method 'can 
ne advantageously employed in the examination of tlte com- 
pounds of antimony that ore used in medicine. 

Gopper, — By this operation, arsenite of copper is reduced to 
metallic copper and metallic arsenic. 

SUmr. — Arsenite of silver is reduced to metallic silver and 
metallic arsenic. 

Mercury. — Calomel, corrosive sublimate, cinnabar, and nitrate 
of mercury, all undergo reduction. The smallest quantity pro- 
duces a brilliant metdlic sublimate. When this is slight, it can 
be gathered together by a wet platinum wire, and brought out 
of Uie tube into a wal<^ glass. 

Si/cer, the Nitrate and Chloride. — Both are easily and com- 

M. Tlka tivo tralni at golpbUe of eofpor uid tiro giiliu of duicoil In jHwdsr. 
IfnlU Ibem Hptntelf Id ■ ipsaii wltli ■ eorar or ■ imnU cnulbls oc glug tubr. to 
Irte Uum from irBUr. Mix ud hMt ttaem in ■ tube, u directed in tlw Icxt, ud 
obieire tbe THolta of U» de«ini>«l^>i. 

II' Repeat the eiperimeDt with iu)phUe oF lima nr lalphnle of tMu-rles. Yoa 
irtlL Ai]illb«tD«Uli«rof UiflM tulptiatBi JsopabLaof decompotUloD br thti proeotL 



TUAL or TnsniLiTT. 141 

pletelr reduced, and whsa wathed in the mottar give brilUaiit 
ipongles of meUdlic sUtct. The nitrate deflagrates dmiog the 
nduction. 

Salts of Jnii«wny. AH reduced. 

Ojdde otZine. VPart of the cadminin remains at the 

Sulphate of Zinc, I heated spot, part of it gives a sublimate 

Sulphate of Cadmium.} like that of arsenic, only brighter. 
The following reductions ore effected hy igniting the formate 
of soda so as to prodat^ a current of carbonic oxide gas, and pas- 
sing this over the metallic oxides. 

Oxide of Copper. — A small quantity of dry formate of soda is 
to be put into a glaas tube one~eightn of an inch wide, and six 
inches long. A Uttle dry oxide of copper is to be placed abont 
the middle of the tube, which must be ueld horizontallv. The 
oxide of copper is to t^ heated to redness by means of a spirit 
lamp, and then the formate of soda is'aiao to be heated. The 
latter is shortly decomposed, and a current of carbonic oxide 
gas is diaengased, which, in passing over the ignited oxide of 
copper, speedily reduces it to the metallic state. 

CAfortrfeq/'Siiwr, treated in the same manner, ia rapidly con- 
verted into metallic silver, meanwhile a disengagement of phoa- 
gene gastakea place, which is readily known by ita sharp action 
upon the eyes and noae, and by its splendid white flame. 

Ohbmde <ifLead also eoffers decompoutioa under disengage- 
ment of pho^ene gas. 

SECOND OPERATION. 

HuTTHeSdBSTANCB, AI^NB,SBF0aa TBB BlOWFIFEjINTHBOPBHAIB. 

Objects in view. — To aecertaiu whether or not the substance 

A, is Fusible, 

B, Changes Colour, 

C, Deflagrates, 

D, Intumesces, 

E, Colours the Blowpipe Flame, 

F, Gives off Volatile Matter, 

O, Behaves the same, or differently, in the Oxidating and 
the Beducing Flames. 
Mbthod. — According to the nature of the substance under . 
operation, or to the particular object in view, yon are to support 
the assay either on charcoal, in the platinnm tongs, or on the 
platinum wire. 1 refer you to the description of these supports, 
given at pages 121 — 126. 

A, TRIAL OF FUSIBILITY. 
Ir the Bubstaoce is metallic, or a metallic oxide suspected to 
he easily redudble, or if it contwis oonstituenta of any kind 



■ oglc 



142 ANALYSIS BT TBS BLOWPm. — OPERATION II. 

vMch it ia expected may attack platinnm at a red heat, it mnrt 
be aupported on a piece of charcoaL But if it be oompoaed of 
sabatwices that cannot attack platinum in the heat, it is beet to 
use a thin splinter, and to hold it in the platinum tongs. The 
latter ia by far the best method to ftdopt m the case of the sili- 
catea and variona other minerals, which, conaiatinK of the same 
constituents combined indifferent proportions, are often only read- 
ily distinguishable from one another by their different d^frees of 
fusibility. The sphnter for this porpoSe ia atruck &om the 
mineral by the hammer, or is chosen from among the fragments 
produced by folding a piece of the mineral in paper, and crush- 
ing it on the anTU. The point of the splinter b held to the 
fl^ne, and the effect ia easy to be Been. Infusible minerals 
preserve the sharpness of their edges. Those which are diffi- 
cultly fusible become ronnded on the edges. Those eafdly fusible 
melt to a round bead. When you are nncertain whether or 
not the substance thus examined contains a reducible metal, yoa 
must take core to remore it from the fire beibre the fused por- 
tion of the assay comes near the platinum support. A splinter 
of sulphuret of antimony, held in the platinum tongs, may be 
fused upon the point without injury to the tongs; but if yott 
allow the fusion to proceed till the melted antimony touches the 
tongs, the instrament becomes injured. To provide ag^nst this 
accident, whenever you perceive the assay to fuse readily, you 
shonld remove it from the tongs to a plate of charcoal (poge 123), 
and renew the fusion thereon. If the sabatance for examination 
is in small grains, one of the gmns must be laid in the cavity 
upon the charcoal. If it ia in fine powder, a small quantity of 
it muat be kneaded with water into a paate, and spread thinly in 
one of the little cavities upon the charcoal, where it can be uied 
before the blowpipe into a thin cake, and then be lifted by the 
platinum tongs to be farther heated. Whatever the support 
may be, the assay must be brought gradually into the blowpipe 
flame, and finally be held forsome time in its hottest part. The 
oxidating flame is to be first employed, and afterwards the redu- 
cing flame. 

Fusibility op the Metals. — Most of the mctala/u«e before the 
blowpipe, and, excepdng the noble metals, become oxidised on 
exposure to the outer flame. Of the noble metals, GDld and 
Silver both melt, without suffering any further alteration. Pla- 
tinum^ iridium, palladium, rhodium, and osmium are all infiiai- 
ble ; but the last by exposure to the outer flame, becomes oxi- 
dised, and volatilises in the state of osmic acid. All the salts of 
the noble metals, such as the nitrate of silver, and the chlorides 
of silver, gold, and platinum, suffer immediate reduction to the 
metallic state, when heated in the inner flame. Of the other 
metals whose oxides can, with the help of soda, be reduced to the 
metallic state, by a process to be hereafter described, the fol- 
lowing are infiiaible— moiyftrfenum, tuitgiten, nickel, cobalt, and 



CirPBLLATIOM. 143 

iron. Among the metals which hsre not been named, are Mreral 
that are infusible, but they are all such aa cannot be reduced to 
the metallic iitate by means of the blowpipe.^' ^ 

Cttpeiiation. — This operation is reeorted to for the pnipose of 
Beparotinr what are called noble metals bom those wluch are 
moie readily convertible into the condition of oxides. The oper> 
ation consista in fusing the alloy on charcoal with pure lead, and 
then heating the resulting bead in the oxidating flame, upon a 
Eubstance sufGcieotly porous to absorb the fused oxides produced 
by the ignition. Theprocese terminates in presmting ahead of 
tne noble metal free from admixture of oxii^bie metalB. A coEt- 
dition of anccesB is, that the alloy produced with the lead be fusi- 
ble. If lead alone does not render it bo, it is neoesaary to add 
tilver, which muat afterwards he separated by solution in an 
acid. I give the operation of cupellation a place here, because 
in the event of sirople JiiMon before the blowpipe producing a 
bead of silver, gold, or other noble metal, it is proper to try 
whether the metal so produced is pure or contaminated with an 
oxidable metal. The method of proceeding is aa follows. Take 
a small quantity of very finely pounded bone ashes. Mix it in 
the palm of your left hand, by means of a knife or spatula, with 
a little carbonate of soda, and a drop or two of water, into a stiff 
paste. Make a hole In a piece of charcoal simiiar to the cavity 
depicted at page 123, but with thelai^r end of the charcoal borer, 
page 123, and about a quarter of an inch deep. Fill this hole 
with the stafT paete made with the hone ashes, smoothing the 
surface by pressure with the round end of a pestle, and uowly 
dry the mass over the flame of a qiirit lamp, or before the 
blowpipe. The soda serves to make the paste hold better 
togetner, but is not essential to the operation. The dried paste 
is called a cupel. Upon this cupel the alloved metal is placed, 
and exposed for a considerable time to the heat of the oxidating 
flame. The lead, copper, tin, and otlier oxidible metals that 
may be present in the alloy, then become oxidised, and form 
fusible compounds which sink into the cupel, while gold, silver, 
and other noble metals remain in a brilliant globule upon the 
surface of the cupel. This method of assaying is so delicate that 
it almost always produces a bead of silver, when the common 
lead of commerce is submitted to trial- Of aU the noble metals, 
only ailvco' and gold can be obtained in fused beads by this pro- 

58. Tilu m pliti or chirial, moimted u Aciira It 
fttt \iX Pat ■ Wt of uitnta r^ ■Utft, th« iIh of » 
^ii*i beid, iDta tlia avltj. a, lod cipsH U ta tha ic- 
dndof dux of Ibe blowup*. In & iboit tiaia tha nit 
l)dennpa«d,udfacllUulHnlUo(UTei«waan>>pOD 




144 AMALTBIS BY TRB BLOWPIPI. OPXRATION II. 

cese. The other metals produce only a grey invisible metallic 
powder. 

Fdbibilitt of TtR Mbtallio Sn,ntrBFn. — Most of the metaUic 
ntlphuretfl fuse b^re the blowpipe on charcoaL llik is eroi 
the case when they contain metels that produce in&sible oxides. 
Many of tbem acquire oxygen during the fusion, disengage bu1~ 
phurous acid, ana produce metallic oxUcs.^ 

FijBiBiLiTY OF THE Mraluc Oxtdb8. — Most of the pore'metallic 
oxidefl are infnsible. Many of them ore susceptible of iKing 
more highly oxidised by the outer flame, and of being partially 
and fwmetuneB entirely reduced by the inner flame. 1 shall 
class the invisible and the ftiaible oxides separately. 

luftuible Oxidet. These are as follows : — 



{Their Hydrates and Carbonates are 
Aiuble, but are speedily reduced by 
ignition on charcoal, and then act as 
inftudble oxides. The Carbonate of 
Berytes is by &itaore fusible than that 
of Strontian. 



Magnesia. 

Aluminiu 

Olncina. 

Yttria. 

Zirconiv Gives an extremely powerful light. 

Silica. 

Tungstic Add. 

Oxide of Chromium. 

in chuRwil. la tb« oildattiig 



tfr, nd imtti It In tlw ftm df 
in tk»<airUr of 

■ pieea of dwcwl. Drr ud Ignll* U Man the Mowptpa. Yon will ftod it to b* 
Infotilile, ud thUwheDttnniclTtiMt^ ttiUsH wltb* TcrjbriflitHgU. 



YoD will And tint Done or thaa (Btki an bg hued, but Ikit tbarildna wUk Afte- 
ent drgreu anight when ODderilraiiclgBttloD. TkeligfatlbUli gtvanhrnliim. 
Ink, for maple, U whoUj iinUke that gina hj Hme, both In biUllncr Hid tlnga 
otcnlonr. Henca. whm iloiii ii Ignltsd, TonaoliiferfnniitheUiidirfUfhIwIiMi 
It diiplifi, tlBt tta* airth preHst la the alt it not lime bat •Inmin*. In tb« exs. 
■dnaUon of lUlMou mluenla, tta« «rth frUi« Ibir untilTi In gnMnt quulitT (Ul 
MDMtliiiM be iirettr aecanttij infeiTed (roD the Und u( Ufht dlii^Tod bj the ml. 



OF OXIDBS. 



145 



Jnfitiibk Oxide», continued. 

f Reduced in the inner flmne to vola- 
AntimonKnu Acid. J tile oxide of Antimony, and to fusi- 
[hU metallic antimony .^s 



TanttJic Add, 
Titanic Acid. 
Uranium, Protoude. 
Uraninm, Peroxide. 
Cerium, I^otoxide. 
Cerium, Peroxide. 

^, Peroxide. 



Iron, Peroxide. 

Nickel, Oxide. 
Cobalt, C&de. 
Tin, Protoxide. 
Tin, Peroxide. 



B«duced to Protoxide. 
Changed to Peroxide. 

{If strongly heated loses a part of 
ita oxygen, and becomes biown.^ 

r Reduced by the inner flame and 
J anblimed. It is yellow while hot, 
~k and white when cold. It diines with 

V.8 bright greenish light while hot,*" 

r Soduced by the imier flame and 
J Bubtimed, if heated on chaicoaL The 
~i deposit is red when cold. It is much 

(^eaaier volatilized thwi oxide of zinc. 

C Deprived of part of its oixymi in 
< the inner flame, and rendered black 

\ and magnetic.^ 



Takes fire and bums into Peroxide. 

{Con be reduced in the inner flame, 
but not easily without fluxes. 

Fvtibk Oxidet.—They are very few in number. 
Oxide of Antimony. Sublimes after fusion. 

Oxide of Bismuth. Easily reduced to metal. 

33. B«M ■ Httla uttMWBlaai mdd on ckuuMl befan tlw blawiilp*. la tba 
oiUadng Dams it b iDhulMa. In th* Inur Busa H la ladnced, girliig ■ lubU- 
nwta af valatila white oxida ofaotlminir tui a b«»d dT fodUa maCillIc aotiiiiaDf . 

34. Il<a>itrai^lraackiR«lbeforethaUowp)pe,iiiniiIl4iiiiititjDfUedioxU« 
of mugmnefle- Yon win find it W be ooiiT«t«d into the brown oiida of nunga- 
aae, in wUdi lh«a !• lot oxj^au in proportion to ths qoAJimy of metal, 

16. Heat K imalliiiuntity of oxide or line In ■ csTit; on Charcot flnt in tbe 
idda t iaj fleina, uid sfterwardB in the rt^ating 6mjaB. Tbe oxide h wbita wbcn 
eaU, bat tunb yeUow wlien heat«d, aod ■hioeg witb ■ pecollv gma llffht. In 
tb# redudng &une> tlie oiide iarflda«d.»fld tbtmatiilliaiibUiDed. Whan die re. 



mll^tap 



until qnantllT oT red oxide af In 



impQon of migsMiini. 



146 ANALTHIS BT THE BLOWPIPB.— OPXRATION U 



Fiuible Oxides, continued. 

r Easily rednced to metal. Red leftd 
turns black when heated, uid pro- 
Oxidei of Lead. < duces yellow oxide. The yellow oxide 

I fiiBes to a brown gloBs, and ii then re- 
Induced. 
Oaa.ofO.ppo. |JJ^K..bMib«d,uidi.lh.,i 

.. J- . ij f Fuses on platinum foil to a red 

Vanadic Add. ^^^^^ ^^^^^ cryrtaUiwa on cooling. 

, Smokes andfii»eeon platinum foil to 

1 B hrown liquid, which becomes yellow 
Holybdic Acid. < and crystalline on cooling. In the re- 

i ducing flame it turns blue. It is re- 

^ducible on charcoal. 
~ „ . , ^ 1 f Fuses on platinum wire. Upon 

Tellunous Acid. (charcoal, it fuL and is rednced.^T 

FtJSIBtLtTT OP THE BlMCATKS AND OTHER MlNBKALS. The trial 

of fntibility is very important in respect to sihcates and other 
minerals, which, conmsting mostly of earths, and containing no 
metalsinreraarkable quantity,haTe scarcely any other pyroguos- 
tic character than different degrees of fusibility to distinguish 
them from one another. As before remarked, the beat way to test 
the fosibihty of minerals is to hest a thin and pointed splinter 
held in the platinum tongs. Seepage 124. The splinter must 
he very small and thin, because the hottest part or focus of the 
flame is in itself small and therefore nnfit to ioTitte a loig* ob- 
ject. A tabular view of the different degrees of fusibility of the 
most important minerals, will be given m the description of the 
" Fourth Operation," which will also contain an account of a 
method for the still closer discrimination of minerals, by an ex- 
amination of the products afforded by their fuaion with carbon- 
ate of soda. 

FiTsiBiLTTV OF Soluble Salts. — Most of the salts and saline 
compounds that dissolve in water, melt when ignited on char- 
coal before the blowpipe. They often, however, suffer a prompt 
decompoution, and produce an infusible base or oxide. When 
they contun water of crystallization, they first melt in the wa- 
ter, then become dry, and afterwords undergo the igneous fusion. 
The alcaliue salts, aFter fusion, sometimes smk into the charcoal 
aud disappear, and sometimes form glassy beads. ^' ^ 



38. HMlDponclMrcoal BuuU qnuUtTofculKniati oftodii. It nwlu and ^ki 
Wmi ft dflv nrand glau beid. 



CHANOBB Off COLOUR — DBFLAOB. — INTUHBSCINCB. 147 

, FuaiBitiTT or Ipjsoiublb Salts. — Some of the insoluble salts 
fiiBe to beads, whick on cooling oiystaUize. This is strikinglv 
the case with the Phosphate of Lead, of which this property is 

the characteristic phenomenon.^ 

B. CHANGES OF COLOUtt PHODUCED BY IGNITION. 
All organic bodies become black or charred. Other changes of 
colour experienced on exposare to heat, are frequently occa- 
sioned by the prodnction of new compounds ; but there are a few 
substances which bars the property, independent of alteration 
in composition, of changing colour with change of temperature ; 
and which, after exposure to heat, resume on cooling their ori- 
ginal colour. For such subslanceB this is a characteriaing phe> 
somenon ; it is of use, however, in only a few cases. 

rThese two compounds are white when cold. 
Oxide of Zinc. J and lemon-yellow when hot. This is the 
Titanic Acid. "1 case with several other white sabstances, but 

\aot in quite bo remarkable a degree. 
Minium. fThese are red or yellow when cold, 

Peroxide <rf' Merauy. ) and black when hot. The tamperature 
Chromate of Lead. "1 must never be raised so high as to de- 
Chromates in ^eueraL (^compose them.^ 

Peroxide of Lead, f The common colour of these substances 
Oxide of Bismuth. \ becomes deeper on exposure to heat. 

C. DEFLAGRATION. 

Several species of salts on b«ng heat«d on charcoal distinguish 
themselves hv defla^vtioD or explosion. These are the Nitrates, 
Chlorates, looates, Bromates, and Chromates. The deflagration 
ofthelastisfeeble.^ 

D. INTUMESCENCE. 

This character distinguishes the following minerals from all 



to. Halt ■ mull foutitr of ^mplutc nf Ind on clurcwl In Che oildUlng aim». 
Wh«D compIeM; rmed lokbud, lUowlt taeooi, Vnu nlU <Ud It. trbca tati, 

the pUdea ot lnip«rf«ct CTyitkli, tach u tbow of Pyrope. 

41. HtU gcnclj DD cbaniMl Id Uw uidalliig fame • inull qiuutlty ^lhi<r uf 
nlnliim or ot chiainMB of lead. Otxerre the dvnge ot colour when liot. wd tKn 
n*(nl of Um orlgliul Galom whm Ua mlKtince becomei enld. 

41. RcM ■ ■uUqnuUtTtfBUniteor pnCuhoacliiKMl befon till btoirpipr. 
Tka Mlw*f™ <> •ImiUr to that ptvdaccd by dropiring cbunnl poirdar Inla 
BdM olnta nl pocub (|«ge IIS), 



I , Google 



BT TRB VLOWPIFB.— OPXaATIOK II 



.^.^ 


"^eC^r"" 


Tht2Mlttf,-amtly— 

6.Mmh 

6. Aiuldma 

7. ThomBnlta 
B. Stilblla 

9. Eplilllbits 

10, H»ukndlta 

11. BnmittHia 

14. 8col«i1ta 

15. PMhntW 

16. EdingtMiiM 


Onkorin* 
Bonwile 
HydrobonciU 

Daldrts 
Botrsolite 
AxinlU 
UydraElhBlaorMu)- 

Sa.poli.er 

a. Mtlonlta . 

b, Wamerita 

d. E)£Cr|ila 
Elsolila 
Idocma 
Carina 
Orthlla 


Epidola 

Gram Tmrmallne 
I^nilile 

MlM.lrom Granite 
Hombland. 

Sphena 


Indtdble. ' 


AMchiniU 
Suiplut« or AluiBini 



E. PRODUCTION OF COLODBED FLAMES. 
Sbtboal sabBtasces communicate very striking colours to the 
blowpipe flame, eithet when exposed to it alone, or when mixed 
with particolai re-agenta. The chuacter is Teiy definite, and of 
conaiderable importance. The colours commonly produced are 
bine, green, yellow, and red. It ia in general the outer portion 
of the blue oxidating flame to which cdonrs are communicated. 
The experiments require to be made in a dark room, and with a 
very sinall flame. The substances by which coloun are pro- 
duced are as follows: — 



Blue Flamei. 




Large intense blue 


Chloride of copper 


Pale clear blue 


Lead 


Light blue 


Arsenic 


Bloe 


Selenium 


Greenish blue 


Antunony 


Blue mixed with green 


Bromide of copper. 


Green Flame*. 




Very dark green, feeble 


Ammonia 


Dark green 


Boracicacid 


Dark green 


Iron wire 


Full green 


Tellurium 


FuU green 


Copper 



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PRODDCTION or COLOUItXD FLAlfM, 



Okm Flamei, eontintud. 

loteiiBe emeralil green 

Emerald green, mixed with blue 

Pale greea 

Very pale ^ple green 

Intense nhitish green 
. Zellow Fkanei. 

Intense greenish yellow 

Feeble brownish yellow 
BtdFiamet. 

Intense crimson 

Reddish purple 

Reddish purple 

Violet 



Iodide of copper 

Bromide of copper 
Phoaphoric acid 
Barytes 



Strontian 
Potash 



Such are the colours and the substances which the Colours in< 
dicate. It may not be improper to mention the circumatances 
that are Ibund to ba foTourable to the production and observa- 
tion of these colours. 

Water, — If a splinter of almost any mineral is held in the 
oxidating flame, close before the point of the inner blue cone, it 
exhibits a slight brownish ycDow flame, extending as a tail a 
short way beyond it, but having little intensity, and soon dis- 
appearing. 1 attribute this to the presence of water. 

Soda. — If a little sulphate of soda is melted on a platinum 
wire, and exposed to the same part of the blowpipe flame, it 
exhibits a long and brilliant stream of greenish yellow light, 
such as can be produced by no substuice free from soda. 
Even'^ salt of this alcflJi, metallic sodium, and every mineral 
of which it is a constituent, gives the same yellow flame. The 
manner of exposing a salt of soda to the flame of the blo' — '" " 
is shown in the following figure ; where 5 is the blowpipe, 



oxidating flame, c the platinum wire upon which the soda of salt 
II fused, and d the tail of yellow flame, by the production of which 
soda is distinguidied.*^' **■ " The wire must be scrupulously 



luoe. Otaoreiil 

produced, and U 



Be uif sale of BodH In tli 



ler, «od yoowUl prodoo 



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150 AMALTBIB BT THE BLOWPIPB. OPBKATION II 



cleaned, and must be wetted in distiUed water to make the b^ 
adhere — nef>er in the mouth, becanse the salira contains silfficient 
Boda to colour the blowpipe flame. -\ 

FoTASB. — If a little saltpetre ia treated in the some manner, it 
exhibits a reddish or yiolet-coloured flame, the form of which is 
short and spread, and not tail-shaped, like the soda flame. It is 
also of but little int«nBity ; and tnoueh characteristic of all the- 
compounds of poto^ it is scarcely e^bited visibly by some of 
them.*6 The presence of a three hundredth part of soda in ed- 
mixtnre with a potash salt is sufficient to overwhelm the potash 
flame, and make the colour of soda predominate. On this a<v 
count, when the two alcaliea occur m the same mineral, soda, 
alone can be detected by this character.*^ 

The only method of detecting by the blowpipe the presence 
of potash is a mixture of potash and soda, is to fuse a clear bead 
of borax on the platinum wire, (see Sixth operation,) then to 
melt into it a smdl quantity of oxalate of nickel, so as to give it 
a brown colour, and finally to fuse with it the substance that 
contfflns potash. This changes the brown colour of the nickel 
bead to blue — while no such change of colour occurs upon the 
addition of a salt of soda. 

Salts of soda and potash ore distinguished from those of earths 
and metals, by fusion with carbonate of soda upon platinum fail. 
If any solid infusible substance appears in the fused mass, it in- 
dicates the presence of some other substance than an alcali. 

SrsoNTriN. Hold in the platinum tongs, point downwards, a 
bit of chloride of strontium moistened with water, and let it 
dip into the blue cone of the oxidating flame, nearer to the wick 
than to the point of the flame. At the instant of touching, a bril- 
liant crimson light shoots along the upper part of the £me. 

The annexed figure exhibits the method of msking this ex- 
periment. Letter b represents the nozzle of the blowpipe, 
a the Hue cone of the oxi- 
dating flame, c the points 
of the platinum tongshold- 
ing the moistened assay, 
which is represented by the 
little circle just overo. The 
outline ti represents the 
form of theflash of coloured 

rasU ^ece of cfptnin, h^lil in Ibe 
I form oT the y«llDw flame produ- 

rUchexhiUtattiaKHlm 

ifT» unl oi^^rrt t\e violat- Mlonred aod tlinrt 
oCpntadi. The uUi uf paiBdi Unit gire the rlolet awM most di*- 
emidato give » Jong * uu of SEoie aa that produclMe brnlnnf 




.^ ^ pRODtrcTioN OF coLOCKXs rLAins; 151 

flame whkh Is proda<!ed ttie inetaot the bss^ ccmies into contact 
viththe blue cone of the oxidBtingflame. 'Hie blue cone should 
be made as free aa poeable from white light. The platinom 
tongs most be carefully cleaned for this experiment. 

Any salt of etrontiui that diasalTes in water, acta in the same 
manner. The colour is not Been bo well if the aaeaj is not 
moistened, nor is it seen so well if an insoluble salt is made use 
of. If the assay, instead of being dipped into the upper part of 
the ftuno, is held at the point of it, in front, as directed in the 
trial of soda, the colour is not so well developed, and after the 
salt melts, the colour is seen no longer; these different methods 
of proceeding are necessary with different substances. Stron- 
tian, indeed, will colour the flam« both ways, but other suh- 
stsnces will not. 

It may be stated as a general rule, applicable to salts of the 
earths, but not to salts of the alcahes, that soluble substancw 
should be moistened with their proper solrenta, and dipped into 
the flame; while insoluble substances should be held in a diy 
State, beyond the point of the flame.**' ** 

If carbonate of strontian is to be tried, it must be moistened 
with muriatic acid instead of water. It then acts the same as 
chloride of strontium moistened with water. If sulphate of 
strontian is to be tried, it must be finely pulrerised, mixed with 
cliarcoal powder and grease, spread thinly on the charcoal, and 
strongly heated in the reducing flame. By this process, which 
is Hofiiciently troublesome, it is reduced tosulphuret of strontium 
and rendered soluble in muriatic acid. If the reduced matter 
holds together in a eake it may be lifted in the platinum tonga, 
moistened with muriatic acid, and dipped in the upper part of - 
the flame, upon which it will give the crimson light. The sul- 

Ce of strontian in its natural state, gives a slight crimson 
e when held at the point of the blue cone, hut it is not very 
distinct,*' 

LiTHiA. — What has been sudof strontian appliee to this aleali 
almost verbatim. The colour of its flame has, nowever, a slight 
tendency to purple, though the difference is not great. The 
flame, moreover, is distinctly produced before the point of the 
blue flame, and is particularlv durable, especially when chloride 
of lithium is employed, while chloride of strontium submitted 
to the same experiment, colours the flame but for an instant, 
the colour disappearing as soon as the salt melts- The minerala 
that contain litnia seldom exhibit its crimson flame, in conse- 
quence of the presence of soda. A fiux consiBting of 1 part of 

Dnb, Ibe wlMmd flum prodiiesd bf 
r, br nitriLUr of itrfHKtaa miriBl^Md 
ui mi^tooad wilta murlaiie add. 
H produMil by Uw nma hIU twid dr> u tha pdiitt of tha 

rimeat an ths reiiuctlun or lulphue at itrontisD to lul- 



152 AMALT<U BT TBI BLOWPIPE.— «rBKAT10N II. 

fluorapar, and 1^ paitBof bisnlpliateof potaih, finely powdered, 
mbuo, wtd heated beibre the blowpipe with olicatea contaming 
litbia, sometimea occastons the proaoction of the red flame. 

LiHB. — The remarks made on. Btrontian apply ahaost equally 
to lime. The colour of the flame is not greatly different, when 
arra^nite and pure calcareous spar are moistened with moiiatie 
acid, and tried as before directed, they piodace a crimson light, 
Tery difficult to be dlBcriminated from that produced by atron- 
tian. It is, perhaps, more of a purple hue, but the diflercnce 
is not such aa to distinguish one earth &om the other with guf~ 
ficient precision. 

The remarkB on the influence of solubility and insolubility, 
and on the management of the carbonate and sulphate of stron- 
tian, apply exactly t« the salts of lime.^'' ^ 

BiRn^. — The soluble salts of this eaiih dipped in wat«rand 
then in the blue flame, in the tama way as the salts of strontian 
and lime, produce a bright apple-green flame. Barytee exhibitu 
little or no colour at the pomt of the blue flame. It shows 
scarcely any colour if not moistened, and its insoluble salts pro- 
duce hardly a vesti^ of colour. 

If the acetate of baiytca, moistened with water, is dipped 
faito the flame, it exhibits the green light; if it is suffered to 
lium to carbonate, it exhibits no light. If the carbonate is 
moi^ned with acetic or muriatic acid, it again exhibits the 
green light. 

These eiperimenfa prove that solubility in water is an impor- 
tant requisite for the production of coloured flames by salts oi 
theearths.'» 

Chloridsi. — Iodides. — Brouidbs.— I class these compounds 
together, because they are all discriminated by the same experi- 
ment. Take a very fine copper or brass wire as thin as fine 
sewing cotton. Bend the end of it into a rina about one tenth 
of am inch across, and twist ihe wire across the middle of the 
ring, so as to make a fignre somewhat resembling the Qi«ek 
letter r, aa shown in the following cut:— 



HpeilmeDts, em^dajing cUnrida of bariuD, idlnde vf twrjKe, 
a,aGvai« oEbHryt«B,iuidtu]phftt«of baFytpSfiqATQKpHVIAvx- 
lta Iff tli«e cwttu in |wci«at«d tor ^juialiAtim w fiaqu^qUy. 
ta be aeqnalaled wUli tti^ InUtudH. 



FKODOCnOK OF COLOUOED FLAMES. 153 

Melt B little microcosmic salt in this rinff, the complex form of 
vhich is intended to prevent tbe salt from dropping &om it 
when melted. Apply a gentle heat, and desist when the melted 
bead has done e&cireMing and has acquired a ptJe green colour. 
Add to this bead any substance suspected to contain chlorine, 
iodine, or bromine, or any of their compounds. A portion, the 
sixth part of a pin's head in size, is sufficient. Then plunge the 
bead suddenly into the oxidating flame, exactly before the point 
«f the blue cone. 

If chlorine is present, there will be instantly produced a splen- 
did bright blue flame. 

If icdine is present, an intense emerald green flame. 

If bromine is present, a bright blue fiame with emerald green 
edges." 

The end of the brass wire is to be cut off and thrown away 
after orery experiment, so as always to leave a new support for 
succeeding trials. 

BoRACio Acid. — The borates aie mixed with two partsof&flnx 
fbnned of 1 part of pulverised fluorspar and 4^ parts of bisalph- 
ate of potash. The mixture is applied by water to the end of a 
platinum wire, and held at the point of the blue flame. Soon 

after fusion takes place, a dark neeii-coloared flame is seen 
merely for an instant. This is Dr Turner's process. I find 
the green flame of boracic add very easily producible by doping 
the borates moistened vrith sulphuric acid into the upper part 
of the bine flame, as directed for strontian. The flame is much 
more distinct in that position tb&n at tbe point of the flame. 
When the borates contain soda, which is very frequently the 
case, in consequence of their beisg prepared with boracic acid 
imperfectly separated from borax, then the dark green flame of 
the boracic acid is ao much afiocted by the yellow flame of tbe 
soda that the colour which is prodnced, more resembles the pale 
green flame of baiytes than it does the deep green flame of bor- 
acic acid. 

If the borates are heated on charcoal with a drop of solphnric 
acid, and Uien moistened with few drops of alcohol. The latter, 
though absorbed by the charcoal, bnms with a green flame 
when presented bMore the blowpipe flame. 

If minerals that contain boracic acid are fused on charcoal 
with carbonate of potash, and then treated with sulphuric acid 
and alcohol, the same green flame is prodnced. This process is 
effective with black tourmaline and other minerals containing 
bat a small quantity of boracic add. 

St. R^put (bli •ipcriniHit wllb ut of tlie eompoandi of Broniaa, lodliw. >nd 
CUcHiiia thHt ;ou eaj ban U hand, II urcecdt area wHh Oie Tolatila hho- 
(woDik. Try «loiii«l, cnmrnoi] ult, cUonU of pain 



154 ANALTBtS BT THE BLOWPIPE. OPERATION II. 

PaosPBORio Acid. — When the plioq)hate8 are moistened with 
■alphuric acid, held in the pUtinum tongs, and placed at the 

Ct of the blue flame, they give a green colour to the outer 
e. The colour ia much pJer than that of the Same of bor- 
scic acid, it is not always produced by the phospbat«a, and it ia 
fiirther distinguished by being piodncible only at the point of the 
flame and not when dipped into the upper part of it. 

Copper. — Nearly all the compounds and ores of copper pro- 
duce a very beautifiil green flame, when expmed to the blow- 
pipe flame. The colour of the flune produced by this metal is 
completely changed, when chlorine, iodine, or bromine is pre- 
sent. The Boluble compounds of copper give a much more beau- 
tiful flame than those that are insoluble, and they act best when 
moistened wit^ water and dipped into the upper part of the 

T^e native carbonate and salphnret of copper require to bo 
moistened with an add. The siilphnret should be previously 
roasted. If snlphnrio acid is used, the flame produced ia a ricn 
xreen. If muriatic add ia used, the flame becomes of that bril- 
liant blue which characterises the compounds of copper and 
chlorine."*- ^- ^ 

Leao. — All the minerals that contain lead communicate a 
beautiful clear blue colour to the flame. There is no difficulty 
in producing it. A thin splinter may be held with safety in the 
tongs, hut small pieces of ore must be tried on charcoal. 

Antwony. — This metal produces a greenish blue flame 

Absehio. — Metallic arsenic produces a very light blue flame. 

Z[Mc. — Oxide of zinc shines when strongly heated with a 
bright green light, and occasionally gives a narrow stream of 
green light, especially when exposed to the reducing flame; 
but it givea no la^e flame, and its soluble salts produce no 
colour when moistened and dipped into the blue flame. 

Tbllubiuh. — The flne green flame of tellurium is produced by 

lirecting the reducing fl ""*■ — "' — '"*"' '■*" "' 

teUurium placed upon c] 

Iron Wire. — Very thin iron wire bnms with a green liffbt. 
The character is of no value as respects the detection of iron, nut 

M. Siimlne crritilUMd nilpliita of ]eopp«r, m AleoMI wlUi wits', mi iipfti 
faito chfl flune. 

M. Hx un ipB ntirfl carboDAte of coppv, mototejud with lalphnrie kdd. 

£7. Euiniine oatJrfi lol^imtaf oopper, lint r«uEedonebftrciHl Id tbe axidatinjf 
Ainifl, ttMn hiU In thfl p^'ti-^-^-^ CopgB, midfltfliafld with njoriAtic Add ud dipped ia 
tba Uiu lamo. 



TOLATILB SUSaTANOBa. 166 

the fact that finely-divided iron do« bum with a gmn flame, 
is necesuiy to be borne in ndnd, in the diBCnmiuatioo of oa- 
known substancea by this character. 

AuHONiA. — The salts of ammoDiA, the instant befote thej dis- 
wpesr in vapouT, on being heated before the blonpipe, produce 
a feeble dark green flame. It can only be seen when the room 
is quite dark, and ia a character of no importance. 

This concludes the subject of Coloured Flames. 1 leconunend 
the student to repeat the cxperimoots till he becomes fiilly mas- 
ter of them. They are eaay of execution, and the results are 
very striking. Many other subotances besides those I have named 
'n the notes will occur to him as adapted for similar experiments. 



nafng the blonpipe, by holding the subBtancea, duly prepared, 
in & small blue flame afforded by a spirit lamp having tiie 
cotton pushed down almost entirely into the wicldiolder or by 
a goa l^ht very nearly extinguished. But the range of power 
banging to the blowpipe fl^e renders it generally preferable 
tot these experiments. 

F. VOLATILE SUBSTANCES. 

As substances which volatilize from charcoal before the blow- 
pipe cannot be caught and subjected to &rther examination, 
they can be discriminated only partially, by the sublimate they 
produce on the coal, by their odour, by the colonr they give to 
the flame, and by the nature of the &xed residue which they 
may leafe. 

Volatile Sdbstahces. 



«ad Cadmiom 

tismuth Tin (slight.) 

Those which are volatile and give no sublimate, are- 
Mercury Osmium. 

Volatile Oxide*. — All oxides formed by volatile metals are 
Tednced and volatilized by the reducbg flame. 

Many Chloridet, Bromide* and Iodides are volatile. 

Sdenivmy Sulphur, and all non-metallie Elemetiis and th«r 
compoundf with one another, are volatile— some of them, as mu- 
riate of ammonia, give sublimates. Hence, all organic suhstan- 
ce* are volatile before the blowpipe flame. 



0,...,, Google 



ANALraiB BT THI BLOWPIPB. OPBSATION II. 

NOH-VOLATILI 8UB8T&H0BS. 



Cerinm Tin (partly) Palladium Tantalum 

Manganese Uramnm Rhodium TungBten 

Iron Copper Platinum Molybdenum 

Cobalt Bilver Iridium Vanadium 

Nickel Gold Titanium Clumnimn. 

The Salt* of theee Metala, except a few which partially vola- 
tilise undecomposed, snch aa the chlorides of iron, copper, tin, 
and chromium. 

All Alcalies, Eartht, and their SalU. 

The Odoubs produced by Tolatile anhatancea heibre the blow- 
pipe, are thMe : — The odour of garlic which characterisea the 
vapoui' of metallic aieenic ; that of decayed horse-radUh which 
indicates the presence of selenium ; that of burning brimtbmef 
which indicates the presence of sulphurets, and the Tsrious 
odours peculiar to the different acids, and to cyanogen, ammonia, 
and organic substances. 

The odouiB of seleniuni and sulphur are best developed by the 
oxidating flame, that of arsenjc by the reducing flame. 

0. DISSIMILAR ACTION OF THE OXIDATING AND 

REDUCING FLAMES. 

Substances heated before the blowpipe on charcoal are often, 

very differently aflected by the outer and inner flames, or more 

properly spealung, by the oxidating and reducing flames. 

Action of Thb Oxidatino Flaue. — The effects produced by 
the oxidating flame are frequently similar to those produced by 
igniting the sobstance in the open glasa tube, of which 1 shall 
speak in the next section. Frequently, however, the oxidating 
flame is used to prepare substances for more effectual treatment 
by re-agents. Thus, sulphurets and arseniureis are roasted on 
charcoal, in the oxidating flame, with a view to drive away the 
aul^uT and arsenic in Uie slate of sulphurous and aiseniona 
acids, and to obtain their metallic bases in the state of oxides. 

Melak that become Osi^edwhenhealedoncharoeaiin the Oxi- 
dating Flafoe. — Most metals become oxidised, exi^t Mercury, 
^which volatilises). Silver, Palladium, Rhodium, Platinum, Iri- 
dium and Gold. 

If a powder is depowted around the asaay upon the charcoal 
it shows the metal to be of the volatile class. The thicker the 
smoke produced, and &k more abundant the sublimate, the more 



0ZIDATI0N6 AND mXDTCTIOMS. 157 

volatile vaj the metal be hdd to be. The natnie of the metid 
is judged of Srom the colour of the BuUimate, its quantity, and 
its dirtance from the cavily in the charcoal where the metal 
is heated. 

White BnblimatM indioate One I Anenie. 

Tellurium Tin (alight) 

Antimony | 

TeUow mhlimatca indicate Lead Bad Biamiitll. 

Dark Teilow mblimate indicates Cadmium. 

Pale Blue sublimate indicates Antimony, in am&U qaantitr, 
the charcoal shining through tt. 

The aab of the chaicoal sometimes appears like a subl^iate; 
but it is digtingaished by remaining fixed on the same spot 
after ignition in the reducing flame, by which ignition the 
sublimate* are reduced and volatilised. 

Su^ur and SulphureU, aa I hare said, become oxidised, and 
burn witit a bine flame, and give off snlphnniuB acid gas. The 
method of properly effecting the roasting of sul^uuets, I shall 
describe when treating of redaction by soda. 



j^d, oxide of antimony, and oxide of tellurium. 
The presence of arsenic is very injurions to the action of the 
fluxes, and it requires to be cardolly removed by roasting. The 
opeia^n ia, however, of difficult execution. The araeniurets 
require to be alternately heated, yet not strong enough to effect 
fusion, in the oxidating and reducing flames. IffusioD takes place 
before the separation of aisenic is complete, the assay must be pul- 
verised, Toixed with nitre and dafla^ated on the charcoaL By 
washing in the mortar, in the manner described in the article treat- 
ing of reduction by means of aoda, the base of the araeniuret may 
be sometimes then obtained in the state of metal or of oxide. 

Carbonaewat Subttanett, (coal, anthracite, &c.) bum bef(»e 
the oxidatinr flame, with or without flame, according to the 
presence or ^tsence of httnmen, Sw. 

Organie Bubttanoa, as already explained, bum with flame, 
and produce chaicoaL 

Action &p tub IteoutRne Fl&mx.— It deprives metallic oxides 
and their salts of a portion or the whole M their oxygen ; pro- 
ducing i^piline metals, solplmiatB, ttc The rednotitms ore ef- 
fected npon chaiooaL 

Rbddoibu Subbtahcss. 
Metai* Redumbh. — Those which are contained in all metallic 
oxid^ exoepting 

The Alcslies Mat^anese Tm^BUn 

The Earth« Iron Vanadium 

The oxidee of Cerium Titanium CSiromium 

The oxides of Uranium l^talum 



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158 ANALYSIS BT TBS BLOWPIPK. — OPBSATIOM II. 

The reduced met&la are of two kinds, vi^alih and find. If 
the metal under examination is of the Tolatile description, 
nothing remains in the carity on the charcoal after the reduc- 
tion. If it ia a fixed metal, you wiU perceive one or more mi- 
croscopic glohules of metal. These are to be taken from the 
charcoal, and examined as to their hrittleness or malleability, 
(page G), and as t« their solubility in muriatic or nitric acid. ' 

MetoBic Salts, the acids of which are volatile, or decompoeo- 
ble by heat, as are all those of organic origin, are without ex- 
ception also reducible. 

Sulfhatet of AkaHet and AleaHnt BarAt are Teduc«d to 
sulphurets, which give sulphuretted hjrdn^n gas if moistened 
with muriatic acid. 

ISetallie Sulphurets, most of them Buffer reduction. 

Chhrides and lodidei, nou'Tolatile and containii^ a common- 
metal, suffer reduction, and give regnline metals. 

Cyanide) and Oxalate* containing reducible metals, become 
cbaned and give metals. 

Not REDcaDLEi 

Metallic Salts, of acids that are not decomposable by heat, 
to wit, phosphates, borates, and siUcates. 

Chlorides, Bromides, Iodides, and Flvoridet, of the metals of 
the alcalies and earths. 

The Sulphurets of the same metals and also of the volatile 
metals — such as cinnabar, sutphuret of tellurium, eulphuret of 
antimony, and sulphuret of arsenic. 

The reduction which substances e^erience in the reducing 
flame, is in almost all cases greatly &CLlitated by the addition of 
soda. 1 shall come upon this mode of treatment in describing 
the use of the fluxes. 

TTsK or Nitrate of Cobalt, — There are several subetancea 
not readily distinguishable by simple lotion, which acquire 
marked characters on heii^ moistened with a strong solution of 
pure nitrate of cobalt, and then ignited on charcoaL These sub- 
stances are alumina, magneda, and oxide of zinc. 
AlumiTia acquires a fine pale blue colour. 
Magnesia acquires a pale flesh-red colour. 
03^ of Zinc acquires a brigbt green colour. 

The sabstsnces to be tned, are to be ignited with the solution 
of cobalt, but not fused — the reason for which is, that minerals 
which contalu lime or an alcali and uo alumina, acquire a blue- 
ish colonr from cobalt if fused, but not till then ; whereas alu- 
mina produces a blue colour by ignition without fusion. Tt^ 
presence of metals iu the assay, destroys the action of nitrate of 
cobalt, and the presence of potash in tke re-^ut is equally in- 
jurious, for it then produces a blue colour ^en it ought not, 
f(H- example with siQca and zirconia. A few other substances 



i,Goo;jli: 



van or NiTRATi or cobalt. 



159 



are ilig^tly affected by nitnte of cobalt, and it u neccsaary to 
be aware of the fact, though the eSecta produced are Dot bo strik- 
ing as to be of use as dtBCTiminatiDgch^acterB. Barytes acquires 
a reddish-brown colour. Strontian, Lime, and several other 
earths, become dark grey or blackish. Bai^tee Jiue* with the 
nitrate of cobalt, but Strontian and Lime do not iuse. Sihca be- 
oomea dark grey, but if rery strongly heated, melts oa thin 
edges to a reddirfi-blae g-Iaaa. Titanic acid acquires a greyish 
black colour, and oxide of Tin becomes blaeiah green. 

Wben a mineral that U to be examined ibr alumina or mag- 
neaia, is hard and solid, ao as not to be able to anck a drop of the 
Bolution of cobalt into its pores, it is neces- 
sary before ignition to pulverise the substance 
in the agate mortar with water, till it forms 
a pap. A drop of this is thea spread upon 
the charcoal, moistened with the solution of 
cobalt, and ignited. If the mass, when bak- 
ed to a cake, loosens front the charcoal, it 
may be liitcd by the platinum tongs to be 
further heated. When it has been heated 
bright red, it mnst be left till it is complete- 
ly cold, and the colour be examined by day 
light. 

The most convenient way of applying a 
drop of solution of cobalt, is by means of a 
small dropping tube, which may be passed 
through the cork of the bottle m which the 
solution is preserTed-°*- "*■ ^ 



UsB or FLro»sp»ii. — Pnlreriaed fluorspar, iree from water, 
fuses with either of the three anhydrous sulphatesof lime, stron- 
tian, or borytes, into a colourless bead that becomes milk-white 
as it cools. It serves to distinguisb these sulphates from other 
minerals, though not from one another. The fluorspai is to be 
nsed in rather smaller quantity than the sulphate. Previous to 
mixture, water is to Im expelled from both substances by ig- 
nition. Only ^e oxidating flame is to be nsed in the fusion of 
the mixtures, aa the reducing flame decomposes the fusible 
compound. 



63. Repmt tlui aiptriisait witta ■ mnll qusnCitT of nilphaM c^ Dutgnetli. an 
SO. Rapwt tlw eipaiuMilt with luldfl or inlptuita ot ilnc. to obUin tb« | 



: C00ji}c 



AMALTSII BY TBI BLOWnra. OFUUnON III. 

THIRD aPEBATION. 



Hbtbod. — Fint ap^y th« flame af the qiirit lamp, and then 
n^ the nme flame witii th« blowpipe. F«r a nan detailed 
account of th« method of perfinniing thu opoktim. Me page 121. 




OsracT or thb ExraniHBirr. — To determine what deaeripthn of 
volatile eubetancee can be produced from the mbjeet (if experiment^ 
hy a curreut qfatmctfkenc air mjting at a high temperature. 

The volatile matters produced by this operation, if gMea 
teeape tiy the upper part of the tube, and are deteded hj their 
odour, or by their action upon test papots, and if vapoure form 
niblimatea on the inner part of the tube, more or lees removed 
from the aasay, according to their degree of volatility. We have 
therefore to consider — 

A, The odour* prodneiUe by this c^ierstkm. 

B, The niMimatM producible by it. 

A, ODOURS. 
They are those of Sulphnrous acid, Sdenium, and Arsenic. 

Odour itf Sul^uroaa Add. — ^When metallic mlphurefe ar» 
heated in this manner, they disengage gaseous sulphurous acid, 
the slightest quantity of which is readily defected by the smell. 
The tube should be held in a position nearly horixontal, while 
the substance is nndergoiiig ignition, and should be immediately 
afterwards brought to the noae, and at the same time be held 
almost upright, whereupon the gas readily escapes from the 
upper end. A bit of moistened Brazil wood test paper, inserted 
at this end of the tube, becomes bleached. Almost every me- 
tallic Hulphuret. disengages sulphurous acid in this process; a 
few, besidea sulphurous acid, give a sublimate of sulphur, parti- 
cularly those which give sublimed solphnr when heated m the 



BUBLIHATie PRODVCXD IN TU OPEN TUBX. 161 

closed tube. (Bee Firtt OperaUon.) This efFect, however, varies 
considerably, according to tbe angle at wbjch the tube is held 

during the ignition. In a few cases, eublimatea difiFerent from 
Milpliur, are given by the metallic Bulphurets, but these I shf^ 
oome to sp^k of presently. The snjphuret of Zinc, and the 
native sulphuret of Molybdenum, give off aulphurous acid in 
this process, with more difficulty than any other of the Bulphur- 
eta. The compounds of metals with Bulpnur and arsenic, which 
have been treated in the closed tube, and partly deprived of ar- 
senic, still give sulphurous acid on being roasted in the open tube, 
for example. Arsenical Iron acts thus.^' ^ 

Odour qf Selenium. — The metallic seleniurets, when roasted 
in the open tube, produce the odour of selenium. There is 
often produced, also, a red miblimale of selenium. 

Odour qf Arsenic. — A few arseniurets produce the odour of 
arseBic. This, however, is only when they are such as prodi 
a sublimate of metallic arsenic, as well as of arsenious ac 



B, SUBLIMATEa 

I ooHB next to conader the lublimalei produced by roasting 
in the open tube. They are of two kinds, white and coloured. 

A, White Sublimates. — These are produced by 
J. Aruuloiu Add I S. Oxlds of BlBmuth l 9. SiJphard of Tin 
2. Uiids or Anltmony 6. Oiide of Lead la Molybdhi Add 

a. Oxide of Tellurium 7. Sulphuret of Lead 11. Mercury. 
4. Chloride of Lead I S. Saienluret of Lead | 

1 . Argeniout A cid. — It is produced by the roasting of arsenical 
alloys or arseniurets. It forms a white sublimate, which under 
the magnifier appears crystalline. Arsenious acid is sublimed 
by different arseniurets with very different degrees of facility. 
Glance Cobalt, and some other ores, for example, require a lone 
ignition with the blowpipe flame. Some of them, as observed 
before, disengage both arsenious acid and metaUic arsenic, while 
sulphuret of arsenic, and substances containing that compound, 
besides the sublimate of arsenious add, commonly give i%d and 
even yellow sulphuret of arsenic, and that too when the tube is 
held almost horizontally. Arsenious acid is also expelled by 
this operation from substances which contain it in quantity 
ready formed, and from substances which ctmtun arsenic acid. 

2. Oxide of Antimony. — It is sublimed during the roasting of 
antimony, of metallic antimoniurets, sulphuret of antimony, 

Bl, HeM B iiDiUt piece of galena Id u op«a tutnl, obgerrliig tbeinitnictlDiiigirra 



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162 ANixraif bt thx BLOwnpi.— «»kition ni. 

and componiids oontaiuing tmlplivTet of antimonv, and aim 
when oxide of antimony, or its oompounda, are tnua treated. 
The sublimate U white, and has the property of being easily 
diiv^ from place to place in the tube, by the application of a 
Tety alight d^^ree of heat. In many cases, howerer, the Bubli- 
mate piodaced by the roasting of antimonioDS Bubstancee in the 
tube, does not consist of oxide of antimony alone, but contains 
also antimonioDS acid. The latter is not a Tolatile substance, 
but b^g formed daring the yolatilization of the oxide in the 
current of air, it is cairied with that sublimate, away from the 
substance assayed. Such a sublimate, conaiBtiiv of oxide of an- 
timony, and antimonioaa acid, is capable of only partial rolati- 
lizatioD by heat. It is geaerally foimed during tne roasting of 
snlphoret of antinumy, . of ctrnqMninds contaming snlphuiet 
of antimony, and of certain antimoninrets, the metals of 
i#hich are readily oxidable. When the eomponnds of sol- 
phuiet of aittim<Hi7 ctmtain lead, aa, for example, is the case 
with the mineral Bonmonite, then the roasting gires a white 
Sublimate which is partlv Tolatile and partly fixed, and consists 
of oxide of antimony ano antimonite of leacT** 

J). . Oxide of TeJlurimit. — This sublimate is formed during the 
roasting of tdlurinm and the telluiets; and by the heating of 
oxide of tellurium and some of its compoonoa. The volatile 
oxide of tellurium forms a ^litw smoke, which is (or lees vola- 
tile than the oxide of antimony; and instead of being driven 
from place to place by heat, like the latter, it has the property 
of melting int« smaU colourless drops. When the teUurets 
contain lead, two sublimates are produced by the roasting. The 
one at greatest distance from the assay, is oxide of tellurium. 
The other consistB of oxides of tellurium and lead, and ia dis- 
tkigniahed by not being fn^Ie into drops. 

4. Chloride of Lead. — This compound, when heated in the 
open tube, sublimes like oxide of tellurium; and the sublimate 
has also the property of melting into drops when heated. It is 
easy to discriminate the chloriiM of lead from the oxide of tel- 
lurium, by other experiments.** 

C. Oa^We qfSitmvth. — It ia formed in the tube by the oxida- 
tion of solphuret of bismuth and alloys of bismuth, but seldom 
by the oxidation of metallic bismuth. The sublimate melts 
into drops when heated, but the drops are not oolourleas like 

63. RoHtB innll^Hieaf DicamswUnionylnaiiapntiilM.iibHniBftttaBiirs- 
f&atJniiB that Imie Wen lHdiit#d oat, ;«;*■ 1^1 ■uA ^SO. ObA^rTA the lubUmUioil 
of white onidp Df AnIinDnf . InrKue the tiibfl at Tariocu adgte* whit* jop 14^; 

tjUtf vitfa vhidi Iba tabUneil nidfl oui be driTen from plu« to pU» In Ihe tube. 
S4. Snbllnj* a rnuIL qnantit; of chloride of Wd In nn open tube, aud applj h«a 
iDthenUknUeaftnlapniltknanlhiiiidH of (hs tobe. Otwm thU, imtewl 
roildaoflutiraMij, it 



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mncTioN aw fluouns. 163 

those of oxide of tellurinm, but brownish or yellcmish. The 
substance operated apon, when bismath is present, beoomea 
covered dnnng the ignition with melted oxide of bimnnth of a 
dark yellow colour, which gets paler as it coob. By this char- 
acter, bismath is easily distin^iushed from Torions other metale. 
It is, however, a character inenfEdent to distingnish it from 
lead, whoee compoundannderrimilar treatment present aaimilar 
occumuIatioQ ot yeUow melted oxide, the colour of which be- 
comes paler as it cools. 

fieudes the white subliiQat«s already described, thrae are a 
few produced by paHicular compoaiuU of certain other metals. 

6. Lead, tn a variety qf Compound*, if heated with substancce 
that oiidate into volatile oxide and acida, generally rises in 
company with these subatances. 

7, 8. Tht SOenittret of Lead and the 5u^uret ^ Lead give 
white sublimates of selenite and sulphate of lead, which become 
grey and melt if heated. 

9. SulphurH of Tin. — It gives a thick white smoke of oxide 
of tin, which docs not again volatilize when heated. 

10 Molj/bdic Acid. — It melts in the open tube and sublimes, 
partly as a white pulverulent sublimate, partly as shining mle 
yellow crystals. When sulphnret of molyMenum is roasted in 
this manner, it gives sulphurous add gas only, and no snbli- 

11. Mercurial CompouTidt. — Mwt mercorial compoaads give 
a sublimate of metallio mercoiy. Bulphuret of mercury sub- 
limes in part undecompoeed, ana partly gives metallic mercury, 
and the latter being more volatile than the former, ia deposited 
at a greater distance from the heated part of the tube. The two 
chlondes of mercury sublime in the open tube without Buffering 
deoompomtion. 

B. CoLouRBD Sublimates are net predudhk by the operation 
of loastiiig in the open tube, but various coloured substancee 
susceptibte of sublimation in the closed tube, sublime also, and 
with atill greater fecility, in the open tube. 6ee the " Fiist oper- 



FLUOEINE. 
1 shall conclude the deecription of operations performed with 
^A» open tube, by detuHng the method of detecting Fluorine. 

In blowpipe experiments, the presence of fluorine is most 
dijhcult of detection in compounds of which it forms an essen- 
tial constituent ; as, for example, in fluorspar and topas, whereas 
in compounds where it appears to be present almost accident- 
ally, and ia in very small qnantitj^, as m some varieties of mica, 
it IS more easy of detection, especially if it huipena to be asso- 
dated with a little water. I have a&eady spoken of ^ detec- 



164 ANALTIU BT THB BLOWPIPE.— ontKATION tV. 

tionof£n<HiDeiiitheIattetcan,(pa8<el34.) Todetecthinmine- 
ralsofthefirstsortadiSerentprocesaiBneceessiy. The fluoride in 
powder is added to a fused bead of microcosmic salt ; the mix- 
ture is inserted into the end of an open glass tube, and the blow- 
f'pe flame is directed into the tube, bo as to strike the mixture. 
y this means hj'drofluoric acid is produced, which passes up 
the tnbe and corrodes its interior surface. This uaA is also 
known by its peculiar odour, and by the yellow colour which 
it conununicatCB t« a moiateued piece of Brazil wood papez in- - 
serted into the upper end of the tube. It is often useful to plaoe 
the fluorine and the bead of fused microcosmic salt upon a bit of 
platinum fbO, beat into a half cylinder and inserted into the Iow<T 
end of the glass tube, so that the flame can be directed upon the 
mass within the platinum^ This arrangement is represented in 
the following cut ; — ^ 



FOURTH OPERATION. 

HEAT TRB BCBSTANCB WITH C&EIBONATE Of SODA. 

Method. — A small C[uantity of carbonate of soda is taken on 
the point of a knife or platinum spatula, and kneaded in the 
palm of tiie hSt hand, with a drop of water, till it forms a stiff 
paste. If the substance to be examined is in the state of powder, 
it is to be worked into the paste. If it ia in a spangle or lump, 
the paste is to be spread upon it, and the mixture is to be placed 
in the cavity of a prepared plate of charcoal (ps^ 1^3), and 
then to be exposed to the oxidating blowpipe flame. There 
should not be more of the paste than will fill half the cavity 
pictured at page 123, A gentle heat is to be applied at first, in 
order to dry the mixture. Afterwards, the heat is Jo be gradu- 
ally increaa^ to its highest point. The assay is then to be re- 
moved from the flame, and to be examined, first when it is hot, 
and again when it is cold. It is afterwards to be ignited in the 
reducing fmme, and ag^n to be examined, both hot and cold- 

Peculiamties RBSPBCTiNQ FnsioN WITH SoDA. — Tho Boda com- 
mouly melts and anka into the charcoal, but, as the heat con- 
tinues it rises and attacks, if it is able to do bo, the solid sub- 
Stance exposed to the flame in company with it. You observe 
a continual cServescence upon the assay ; and, finaUy, that the 
edges of it melt away, and the mass fuses to a bead. WTien the 
Boda is able to decompose a substance, but not to form a fusible 
compound with it, you observe » gradual swelling and change 
of appearance in the solid as the operation proceeds, but no for- 
mation of a bead. If too little soda is added, you sometimes ob- 

65. Repeftt thto exp^rimerit with OaonpftT. 



pirsIOK WITH CABBONATI Of SODA. 165 

Bcire a dear bead surroundiiiK am mtdinolTed BubBtance. If too 
much soda is added, the fmea bead becomw opaque as it cools. 
In the former case, von must add more soda, in the latter, more 
of the unknown fnibstaiice, and foae the mixture anew with a 
view to produce, if possible, a glam wholly clear. There are 
some Bubetancea which give a bead with a small proportion of 
Boda, but onlj a alag when a larger portion is added, on which 
acconnt it is advisable always to benn with but a sm^ quantity 
of soda, and gradually to add fresh dosw, and to obe«aTe the 
effect of each. 

. Fusion on the Platihom Wise. — If the fiuion of a substance 
with soda on charcoal produces no metal, the experiment may 
be repeated with the platinum wire instead of the chaicoal sup- 

Objsiti of this Ofsbatioh. — To detennine whether the sab- 
stance is one that produces a Glass, a Slag, or a Reduced metal. 

A. Only two substances, melted with soda upon charcoal, pro- 
duce clear glaas beads. The character is fi>T tJi»e two substances 
ve^ distinctive, 

B. Many substances, chiefly mineral, produce beads more or 
less fusible and transparent when thns treated. 

C. A variety of substances fuse with soda upon a platinnm 
wire held ia the oxidating flame. The substances which so dis- 
tinguish themBelves are in general the metallic acids. The ex- 
periment ia not, however, one of great importance. 

0. A great number of metallic oxides, when fused with soda 
on charcoal in the reducuig flame, yield beads of metal, or, after 
suffering reduction, exhale TolsUle oxides, and depo^ a subli- 
mate upon the charcoal. 

B. ijid finally, many substances are not attacked by soda at 
all, and neither undergo fadaa nor reduction. The earths and 
some of the metallic oxides are thus characterized. 

A. 8UBSTANCE8 WHICH FUSE WITH SODA ON CHAR- 
COAL, AND FORM A CLEAR BEAD. 
Tbebb arc only two — Silica and Titanic acid. 

SiLiOA. — When silica and soda are heated together on charcoal, 
they iiiM, there ia a discngsgement of carbonic acid with effer- 
vescence, and the silica and soda produce a tran^arent colour- 
less bead. No other substance acts with soda in tne same mui- 
ner. Some of the silicates also taat with soda, but very seldom 
produce a clear bead. When a siliceous compound is heated 
with soda, it melts most readily when it contains much tdlica 
and little base, and has but a small quanti^ of soda added to it. 

Sometimes the glass formed by soda and silica, acquires as it 
cools, a deep yellow or hyacinth red colour. When this happens, 



166 ANALraifl ht thb blowpipk,— ofehation it, 

either the silica or the soda contains snlphnr or a eolphate. If 
tile colonrinK occun with all the glasses prodaced bv the same 
soda mth other samples of pure silica, it proves the mis to con- 
tain sulphate of eoda, in wnich case it is unfit for nse with the 
blowpipe. Bnt if the colouring only occurs in particiilBj cases, 
it is to be inferred that the sulphur is present in the aaaay.** *?■ ** 
TiTAMo Aois. — Soda and titanic acid fuse on charcoal to a 
yellow glass, which on cooling becomes grevish white and 
opaqne. It is never g^uite clear, like the glam formed by silica. 

B. MINERAIB WHICH PRODUCE BEADS OR SLAGS 

WHEN HEATED ON CHARCOAL WITH SODA. 

I shall divide these Minerals into, the foUowing classes.'— 

I. Minetttb that are Infiisble 'i 
11. Minerak tiuA Fuse to Beads Vwhen heated alone. 
III. Minerals that Fuse on the edgesj 

Only OxidUed substanoes are embraced in these Tables, — No 
Snlphurets, Arseniurets, &c. 

TABLE L~-IMFUSIBLE MINERALS. 





Proda» B«(t> iritk ft 




P»da«B»da Willi 


JiltleSvda. 




8u4k 


Produce ^« wilH man 


Pntdnce Shgi with Soda. 


Qaarti* 


PhMOkllB 


Thorile 






AndHliulte 


OliTiD. 


SUurolIle 


SideroBhijolIts 


Carite 


GBhlenUe 


Dloptaw 


Cynnite* 


Chroma Gchr. 


Fire-dav* 
Leucite* 


Tile 


Gadolinite 


Uwarowite 




L11hl.jn-U'ounnaUnB 


ChromaU Df Iron 






CirbonatM of ihe 


Ruiile 




Earlhi» 
Glides" 






Frodnu S1i( 


IiirlthSod*. 


Basic Phoipbate ot 

Ytlria 
——— of Alumina 










Peroxide or Tin (Is re- 


Peraulphaia of ln>n 


CyMophaiia 


duced)* 


Sulphala at Alumina 


PolymlgnlM 


Hydiaie of Alumina 


AlumlnKa 


AB«!hjnito 


HydnlaafMBgntsis 




0«ntediiia 


Spinel 


Fluoride of Cerium 




GBbnila 


YilroCTltB 


Yttro-TantalllB 


Wonhite 




Tsnt&llte 


OrbDnBleofZinC 


Corundum 


Oifd«iorlrDn« 


Pschunui 


Pleoniute 


Oiid»onvi>iHnnMi)* 


Zinan 





C-.oogIc 



DISCBIMIKATION OF HIKXRALa. 

TABLE II. 
MINERALS THAT FUSE TO BEADS, ALONE. 



PcodimBtadawltliSgd., 


ProduMB«.d.<rllfc. 


PrBdo«Sl«g. with Sod.. 


The Zedltea" 

SrapolFia 

Sodolit. (Greenland) 

t:ia»li.e 

Mica from FrlmlliTS 

Black Talc 
AcfamitB 

Krokydolitfl 
LfHrite 

GamBt 
Carina 
Helvina 

Boradc jidd 

Tiocsl 

Bonidte 

Datolite 
Baliyolila 
Allnlla 
l,>pi. Umll 
Eudialjt. 

Cryolllg 


Kta 
KsdSiliuiaafMan. 

BluklH>di«alll(st< or 
Manganasa 

Unhlta 
Pvronhite 

Sorriaimlite 

Sodallla 

Fluortpar* 


Brerldta 
Amphod.111. 

Chlorite 
Fahlunlu 

BlS['(*pllSih) Toar- 

iraline* 
Wolfram 
Pharmscollta 
Scorodlta 
Aneitiata of Iron 
Totmphvlina 

SZ& 

Phoaphate of Iron 

Sulphate of S'roiitlan* 
SulphaU of Magneda 
Poljhnim, 
UaujM 


RHliic»d Metal produced 


TungrtaleofLead 
MoljbdateofLtod ' 
VanidiM* of Lead 
ChromalaoTLewl 

Cobalt Blo.m 
Nickel Obhra 
Phosphate of Copper 

Chkirlda of Lead 
Chloride of Silier 



The MineraU that are dUtingviehed t/i the»e three Table* by 
the eign *, are contained in "Griffin's Cabinet or Mineuu ron 
Examination by Ekfertment." 



8T. Repeat tba eiperiisant with eilka ud loda in dffareol [roporliau. 

Si. FueoDe or the mlanrlm h»di tliin proJocad with ■ fooftli part of IM balk 
of ODT lolplvte (ealplata of udaorgyfrtun), Obteera tlie Jallow coloor doa to 
the ^etenca of euliihnr. 



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16S ANALT8IS BT TBI BLOWFIPX. OHUITIOIU IV. 



TABLE III. 
MINERALS THAT FUSE OK THE EDGES, ALONE- 





rrodD»B«4twltk> 






HMsSodk. 




Pro*«.B«ri.w«l.Sodi 


"-"■sr*""- 


rradn«Sl»«.wlUSota. 


SUallM 


TihuUr Spar* 


Stllpntnldarita 




Orallifg 


Plombgonim. , 
S«rp«ntin« 1 


K«l*(nr* 


Hyp«nUi>D<i 


AlUle" 


Epidot. 


SlKoila of MnnfUMi 


PataKta 


ZoUM 


from Ptcdmont 






Mica, from Gnwil** 


Anorlhite 




PlmellM 


Kmanid 




Finite 


Eiukw 




BlD« Dlchniit* 


S<3IX(V«a.lBn) 




KBrphallt* 
Prrochlore 
TuiiKSMteorLtme 
Oni«n (Soda) Tour- 
maline 
Unillla 

Gyp™mS" 







C. SUBSTANCES WHICH FUSE WITH SODA ON THE 
PLATINUM WIRE IN THE OXIDATING FLAME. 

SOica. Piodnces a dear glaw. 

Molf bdk Acid. Clear glass when hot. Milky when cold. 

Tui^tBtic Acid. Clear dark yellow glass when hot. Crys- 
talline, opaqiic,aiid yellowish when cold. 

Ovomivun, Oxide. Deep jsllow gleas while hot. Opaque and 
y^ow when cold. In the redndng 
name, opaque and green when cold. 
On chvcoal, it fuses and is absorbed, 
tmt IB not reduced. 



Tellurium, Oxide and Add. Clear colouilesB head when hot. 

White when cold. 
Utank Acid. Clear deep yellow gUss when hot. 

Crystallme and grey-white whcq cold. 

Not reducible upon charcoaL 
Vanadic Add. On cbarcoal, abaorbed, but not reduced. 



»-i b, GilOi^lC 



' BKDUCINa PR0CBB8 WITH SODA. 169 

r The oxides of mAagaiieee di»olTe in but 
very small quantity; yet in so doing 
I they communicate bo fine a green colour 
M«igo,Me,Md«.-^ I« Ih. »d.^ ttat lbi» beociu. om of Ih, 
" ' I moat delicate expemaents for the detec- 

tion of manganese. The colour is how- 
ever better dereloped upon plaHnwit 
VbU than upon the wire* 
Cobalt, Oxide. Fnaea in smallqnaiititytoa paleredbeod. 

On cooling, it becomes grey. 
Iiead, Oxide. Clear coloDrleas glass when hot. 

Opaque and yellowish when oold. 
Copper, Oxide. Clear green glass when hot. 
fk Opaque and colourless when cold. 

D. REDUCTION OF METALLIC OXIDES, BY IGNI- 
TION ON CHARCOAL, WITH SODA, BEFORE THE 
BLOWPIPE.— 

The reducing operation is performed as follows : The powder 
'' for examination is mixed in the palm of the left band with 
wet soda to a paste. This is put mto the cavity of a prepared 
plate of chareoal, which should be very solid for this experj- 
meat, and not less thtoi half an inch thick. It is then heated 
in a Btroiw reducing flame. A little more soda is afterwards 
added, and the ignition is renewed. And again, so long as 
any portion of the powder remains on the cnrfoce of the char- 
coal, fresh soda is added in small portions, and the blast is 
renewed. The heat must be strong, and the flame must cover 
the whole of the assav-. By this mesiw the mass is made to sink 
into the charcoal. A pretty stxong flame is aJW^uds ibrced 
upon the ^wt for a short time. A few drops of water are added 
to extinguish the fire, and then all the hornt ports of the char- 
coal with the salts that have been absorbed, are cut out with a 
knife and put into a small ^te mortftr, care being taken to lose 
nothing in the transfer. Tlie msse is ground to fine powdet^ 
mixed with water, and Bobjected to repeated gentle decantationa, 
til! the whole of the pnlverised chareoal is removed from the 
mortar, care being taken all the while that no metaliic particles 
flow over with the charcoal. No other precaution is neceasaty 
to prevent this, than that of allowing the contents of the mortw 
a little repose after stirring the water and charcoal together, be- 
fore pourmg off the matters that float. It is proper to use the 
washing bottle (page 80), in this process, when the charcoal 
is entirely removed &om the mortar, the metal, if any was in 
the assay, will he found at the bottom of the mortar. If it is 

£9. Mix ■ gnin or and* trKb the t'nth of ■ gnhi or blub oxlJe or manguof . 
Ignite Ihe mlitnra niKm m allp of platlnnn roll ipAgf S8}. Obtan tbt ■IMD 



170 ANALTBIB BT TBX BLOWPIPK. — OPBKATION IV. 

on inftuible or a brittle metal, it appeara in the form of a metal- 
lic powder. If it is a malleable metal, it produces flat Bhinuig 
platee (see page S). And in almost all cases the surface of the 
mortar exhibits numerous metallic streaks produced b^ the fric- 
tion of the metallic particles during the pulverisation of the 
charcoal. Among the metala moat easily reducible by this pro- 
cess, are tin and copper. 

Should you not happen to possess an agate mortar adapted to 
the performance of the washmg part of the operation, the best 
thing to me instead of the mortiu' is a small porcelain capsule. 
You place this in the middle of a flat dish or soup-plate, grind 
the charcoal in it by means of a porcelain pestle, and without 
lifting the capsule from the dish, wash out of it the lighter por- 
tions of the ponnded charcoal by a jet of water from the wash- 
ing bottle, applied in sufficient quantity U> make the contents of 
the cajole overflow its edge. When the charcoal is all pulve- 
rised and removed by this method, the particles of metal can be 
Been at the bottom of the capsule. 

dlffekenceb in the substances wbicr bvftga reduction when 
Heated with Soda, on Chabcoal, in the Reducino Flaue. 

Some of the metals reduced by this process became volatilised 
by the heat of the reducing flame, and undei^ing a contempora- 
neons oxidation, deposit upon the charcoal, at a certain distance 
from the assay, a sublimate of regenerated oxide. In this case, 
no metallic particles are procured by washing the fused mass in 
the mortar. 

Other oxides reduced by this process, afibrding fixed metala, 
present their results when the charcoal is eeparated by the pro- 
cess of washing already detailed. 

Nearly all the oompoundi of reducible oxides also, are reduced 
when treated by this process. Not only the salts which contain 
oxygen acids, but oven the compountu formed by the metala 
of the reducible oxidea with sulphnr, selenium, chlorine, bro- 
mine, and iodine, although none of these compounds become re- 
duced when ignited la the reducing flame without soda. It is 
necessary, however, when tulphur^ are to be submitted to the 
reducing proces, to roaat them thoronghly in the oTcidating 
flame iMfore mixing them with the soda. The smne precau- 
tion must be token with the compounds of arsenic and selenium; 
for the preience of either of thcae three elements ia very inja- 
tioua in the procesB of rednotirai. 

' Method qf Boatting Su^vreti. --^Aa the metallic sulphurets 
£all very frequently to be eicamined by the blowpipe, and as 
the expulsion of the sulphur from them, and their convei^n 
into metallic oxides, is at the same time a very necessary and 
very delicate operation, I shall describe it in detail. 
If it ia a factitious sulphuret which is to be decomposed, you 



SSDUCTION OF VOLATILE UETALS. 171 



make it into a thin cake by kneading with water. If it is a 
native sulphoret, you choose a rery tmn slice or Bplinter. You 
support it on charcoal, and espose it to the oxidating flame. 
At first, you apply a very gentle degree of heat, and take parti- 
cular care to avoid fuBiou.' If the Bulphuret fuecs accidentally 
you must ix^in with a fresh piece, or else reduce the melted 
portion to powder, and again heat it. When the roasting has 
proceeded to a certain extent, the sulphuret, or rather the oxide 
into which it is changed, is no longer in danger of iuaing. You 
may then increase the heat, and endeavour to reduce the por- 
tion of sulphate which is generally formed during the roasting. 

The slow and gradual application of the heat, is of gre&t im- 
portance. By applying a strong heat, you fuse the sulphoret, 
and cMinot drive off the sulphur. And if you merely roast the 
milphuret into sulphate, instead of into oxide, the consequence 
is, that when you proceed to the reducing process with soda, 
instead of obtaining reduced metal, you only obtain sulphuret, 
and this, combining with the sulphuret of sodium, produces 
a soluble compound, which dissolve in the wash water and dis- 
appears alt<^ether. 

Volatile siilphurets can only be roasted in the opes tube. 
The sublimed oxide can be afterwards gathered and examined. 

It sometimes happens that the oxides to he reduced, are ac- 
companied by irreducible matters that interfere with the opera- 
tion. In this case, it is of considerable advantageto mix a little 
borax wifli the soda; the borax melts into a glass with the 
irreducible matters, and leaves the reducible oxides to the free 
action of the soda. The addition of borax is often of great use 
in reducing some of the compounds of tin. 

Heduciblk Metais. — Gtasa \. — MetaU tchote campoundt gaffer 
redttctiim when ignited with soda on dtarcoai in the reducing 
fiame ; and tuhich produce volatile oxides, and deposit a sublimate 
on the charcoal. These metals are, 

1. Antimony I 5. Zinc 

2. Arsenic 6. Cadmium 
S. Tellurium 7- Bismuth 
4. Selenium | 8. Lead 

1. Antimony. — Particles of reduced brittle metal are easiljr 
obt^ned, which, on being_ strongly heated, give off a thick 
smoke, and produce a wmte sublimate which falls upon the 
charcoal, lliis can be driven from place to place, either by the 
reducing or oxidating flame ; but if the reducing flame is used, , 
the bluish green flame of antimony is produced. 

2. AitsENic. — It givea a thick smoke and white sublimate of 
arsenious acid, d^osited upon the charcoal at a good distance 
from the assay. The sublimate is easily volatilised, and if the 
reducing flame is employed, the odour of garlic is produced. 



172 ANALT8IB BX THX BLOWPIPE. OPKRATION IV. 

3. TiLLirBnui. — It giTW a white mblimate, with reddiifa 
edses. It is eaaly removable by the oxidating flame, or driven 
off 1^ the redocing flame, the latter producing a green flame ; 
or if seleniuin be present, a blueish-green flame. 

4. Sblbhium. — it aflbrds a steel-grey ahiiuDg sablimate, some- 
times a little blufush. The nibiimate is tcadilj' volatilised, and 
in the redncing flame prodocee a bine flame. 

6. Zinc. — It produces no visible metallic cine It gives a 
mbljinAte which is yellow and reflects much light whilfl hot, 
but is perfectly white when cold.^ The sablimate is not volatH- 
ised by the oxidating flame, birt can be driven off by the reduc- 
ing flame. If a drop of cobalt solution is put on the white 
sablimate and healed, it changes its colour to bright green. Mi- 
nerab which contain zinc, apon being heated wiu soda an char- 
coal, deposit a sublimate of oxide of zinc. 

6. Cadhiuh. — It gives no vimhle metal, hot produces a red- 
di^-brown sablimate, the colour of which is best seen when it 
is cold. The sablunat« can be volatilised by either the oxidat- 
ing or reducing flame. 

7. Bismuth. — The compoands of tliis metal readily give par- 
ticles of brittle metal, which crush under the hammer. After 
long exposure to the flame, it deposits a sablimate which is 
darx-orange when hot, lemon-yellow when cold, and in thin 
«oa(s blueiah. It can be driven from place to place either by 
the oxidatii^ or the redncing flame, but gradual^' diminishes in 
quantity. It gives no colour to tho blowpipe flame when vol- 
atilised, by which it is distii^nidied &>m antimony and tel- 
lurium. 

8. Lbad. — Its compounds veiyreadiiv yield particles of metal, 
which flatten under the hammer, and ao not crash like the par- 
ticles of reduced bismuth. It deposits a sublimate which greatly 
resembles that of bismuth, both m its oolonr and the distuice at 
which it rests &om the BBa&j. 

Reducible Metals, Clais II. — Metal* whaw compound* nfffer 
reduction when ignited v>ith goda on charcoal in the reducing 
flame, and which give metaUie grains and no tvblimate. 

These metals are k follows ; — 



1. Molybdenum 


fl. Tin 


2. Tungsten 


7. Copper 


3. Iron 


8. Silver 


4. Cobalt 


9. Gold 


fl. Nickel 


10. Platinum 



The reduced particles of iron, cobalt, and nickel, are magnetic. 
The other meljds are distinguished by their colours, mallea- 
bility, &o. 

Vanadium. This fasea and ^nks into the charcoal, but giv(>s 



BKDVCTION OF FISBD METALS. 173 

When the compound mbmitted to T«duction contains 
several metals, the result ia often an alloy ; but in other cases 
tJie reduced metals are obtained separately, ob when iron and 
copper are present together.^' ?!■ ^ 

Several substances of frequent occurrence are detected by 
processes closely related to the oue under consideration, for 
which reason I shall introduce them here. 

Arsenic. — Suhstances suspected to contain this metal in any 
state of combination must be mixed with soda, and heated on 
charcoal in the reducing flame. Whcreapon the smallest por- 
tion of arsenic produces the peculiar odour of garlic, by which 
the vapour of this metal is characterised. The odour is not pro- 
duced if the oxidating fiamo ia employed, aoi if the soda be 
omitted,^ ^ 

SuLPHcft. — The presence of sulphur in the mlphurels Mid 
sulphates is determined as follows : — The compound is ignited 
with soda, or with a dixture of 2 parts of soda and 1 part of 
borax, on charcoal, in the reducing flame, and the ignited mass 
is placed with a drop of water on a piece of bright silver, to 
which it communicates a yellowiah-black stain. The use of the 

70. TtiMD ndiusing experlmenti t,n at ytrj grtM ImporiBnce, u Uiey glre n- 
Bull) of the moU dedilre Iclnd. and ut npon utrsmely aniHll qnanUtln of Uie me. 
tilUe coR^DundL Tba]r cuuiot blL be made propvrly wllhoiit the help of m unall 
B^te mottar, though a good many opentions can ha perfoinued nith a small 

a Mibitilato for * pciUa- But if you poBaeta an agata mortv. yon shauld tt- 
peat Ba many of (ba procflua » Buflice la make you acqu^tad with the mode of 
openOag. Yon may begin by operoLlng upon bail a grain of oiddo of copper. 
Then upon a quarter of a grain. Theo upon the eighth of h grain. Afterirards 

hy the addldbn of a Qttle horax. then ucumiilidiiig 11 nlth eoda eloae, and work- 
may BDCceed nickel, and to that aeTanl of tho&e that givfi lublimatea ; In tvm-tdii^ 
npon »hlch, you are to obeerre perticulBrly the diilinctite chanaten of the dlff«. 
«nC tnbllmaCH ; ai, for eismple. their diOerent degrees of rolatilily ; th^r different 
rtactloni In the oxidatiiig and redudng Dame j their differenea in the dielantea at 
whldi thay rut aroand the heated ipot ; tlielr different eobjun, hot or cabt ; the 
diltbrentcolouie they glre to the redndnsdame; thebrltUeni 
Ok melale they aSird ; and u forth. 

7\. Yuu may then proceed to the roaating and reduction of 
anlpbureta, uich ai the predpilated lulphureta of tin, lead, I 



TS. 


And Bnally, you may ( 


examine some of the mineral 


.niphnref. anchaal 


Pyril 


les. Sulphuret of AnUmony, Galena, Kid Zinc Blon 


de. The whole of tl 






perin 


lent." The price of thh 


1 lltOe eal^et, wtuch compre) 




porta 


nt minenU, adapted for aipeiimcnti of this kind, i> 




73. 




U vlth a portion of an uu 


inical compound not 


eeedi 


Dsthetehthofagraln. 




reuiltwllti«y*naimi 



I , Google 



174 ANALTBIS BT THB BLOWPIPE. OPBRATtflN V. 

boi'ax is to prerent the sulphnret of aodinm from ainkiiig into 
the charcoal as it is producedJ* 

Or, the compcnuiil is mixed with soda and nlica, andfoaedoti 
charooal in tlie reducing flame till it foims a bead, which, if 
mlphur is preaeat, has a dark-brown colour. These two ex- 
peruaeats oisthiguish solphnr from all mbstaiices except sel- 

SEiiSNiuif.— The CMmpoanda of (elenimn bduve exactly like 
the compoimda of sulphiir towards the plate of aQver and the 
j^OBs of aiiicti deecribed in the last two ezperiraenta. 

But when the compotinds of seleniam are fiiaed with soda on 
chnrcoal in the reducing flame, they exhale the odour of horse- 
radish by which they are sofficiaitly distiugniahed from the 
compounds of sulphur. _^_^ 

MtKERAi: Acids, — A sabataoce Hospected to eontun a mineral 
add is fiised with soda upon platinum foil. The fosed mass is 
dissolred in water, filt^^ aatnrated with acetic acid, and tested 
with a solution of acetate of lead. All mineral acids, nitric acid 
alone excepted, give a precipitate when thug examined. 

E, SUBSTANCES WHICH SODA NEITHER FUSES 
NOR REDUCES. 
Alumina 



The oxides of Uranium 

The oxides of Cerium 

Tantalie acid 

Zirconia 

Thorina 

Yttria 

Olucina 



Magneua 

Strontianl The carbonatet of 
Baiytea / these earthsfiise. 
All the Alcaliea, which sink 
into the chorcoaL 



FIFTH OPERATION. 



Objeot.^-To see what coloured glass it gives. 

Method. — Microcosmic salt, or the phosphate of soda and am- 
monia, is resolved by wution into biphosphate of soda, a flux, 
which, in consequence of its excess of acid, has the power of fii*- 
ing almost every chemical compound except silica. The latter 
Kotens and swells, bat remains expanded m the fused flux like 
a species of skeleton. Microcosmic salt is commonly fused upon 
charcoal, on which it readily forma a round colourless transparent 

14. Repeat thliupsriBMitwlth t«7 BioaU qnuilifln of mlpteuat Mdi,iul- 
|AM«o(llDH,«lpliMaari»pp«,udirlIb«iiTorUHguJphiinti. CommonM wllh 
BqiBMerotBgnlDofltaBiiilpbUaor ■iilpfa"»t, uA rapeuik* aipnimeDt with 
•miller quuUllei, till ron Had the l«itp«U(aiCbU glTu ■ decided remit. 



FUSION WITH MICKOCOSHIC SALT. 175 

bead. (See the figure on page 123.) It cannot be convenientlv 
used on tlie platinum wire in consequence of its extreme fusbi- 
litj, and the readinesa with which it falls from the ring. When 
metallic osidea arc fused with microcosmic salt, the resulting 
bead is exposed altematelvto the oxidBtinK and reducing flame, 
becaose several metals which are euaceptible of being oxidized 
in different degrees, commnnicate difiercnt colours to the flux, 
according to the fiaine employed. A substamce exposed to the 
outer fliune becomes more highly oxidised, and wnea brought 
into the imiei fiame, becomes more or less reduced. And wben 
the difierent oxides have different coIouib, the flux is coloured 
accordingly. 

A bead that has been heated in the reducing flame requires to 
be cooled quickly on removal from the flame ; because slow re- 
frigeration induces a partial re-oxidation. This rapid cooling ia 
most ea^y effected by a current of cold aii blown upon the bead 
from the blowpipe. 

The re-action expected from redaction can frequently be expe- 
dited by plunginp; info the hot melted bead, just rfter with- 
drawing it from the reducing flame, the end of^ a small roll of 
tin foil, (pose 127,) and then again applying the reducing flame 
ibr a secondor two. This has on many metals the same effect 
as the long-continued action of the reducing flame. By this ex- 
pedient, for example, a minute portion of copper in a bead can 
be easily reduced to the protoxide or to the metallic state. 

Oxides which ore diflicult of reduction, and which cannot be 
converted into other oxides, commonly produce the same colours 
in both flames. 

Most oxides produce colourless beads ; but a great excess of 
any oxide generally gives the bead the appearance of white en- 
amel, particularly when it is cold, StiB, the number is consi- 
derable of the metallic oxides, which, on fuuon with microcos- 
mic salt, produce coloured beads ; and lor oxides of this aort 
microcosmic salt is a most usefiil re-agent. 

It is sometimes difficult to determine the colour of the bead. 
The depth of tint depends upon the quantity of the colouring 
matter dissolved in it. Sometimes it is necessa^ to add more 
of the colom^ing matter. Sometimes the bead is coloured too 
intensely, and appears black. ln,Buch a case, the bead, when 
hot, can he squeezed flat with the pincers, or drawn out to a 
thread, or a portion of it can be melted with a fresh qoantity of 
microcosmic salt. The colours of many beads change as they 
cool. Of othera, the colours vary with day light and caudle 
light, and often the colour of a head can be best seen at night, 
by holding it bej/oad the candle^ and not between the candle and 
the eye. 

The colours of beads producible with microcosmic salt are 
shown in the Table at pagee 178, 179.?' 



DPBRATION Tl. 

SIXTH OPERATION. 



OiUBOT.— To me what coloured glass it gives. 

Method. See p^ 12G. — Nearly all BubsUoces diaaolre when 
fused with borax, tooogh some diasolve in it much juok readily 
than otheni. 

The gubttaaeet tehuA dufolve in boras are these: — 1. All 
earths, metallic oxides and metallic acids, except those of gold 
and platimim, which too readily undergo reduction ; and those 
of mercury, which vaporise. 2. Salts of metals, after having 



had their acids dc^royed by ignition. 3. Metallic aulphurets, 
after being well roasted to drive oif the sulphur. 4. Carbonates 
and nitrates, the adds of which are expelled during the fusion. 



C Borates and phosphates, which fuses with the flax without 
suffering decomposition. 6. The compounds formed by chlorine, 
iodine, bromine, and fluorine with metals, (chlorides, &c.,) or 
with metals and o^gen, (chlorates, &c.) — all of which be- 
have pretty much like oxides. 7- Silicates, though sometimes 
slowly. 

Sulphates, sulphites, Beleniates, and selenites, suffer decompo- 
sition when iiised with borax ; but form beads coloured so deeply 
yellow or brown by sulphurct or seleniuret of sodium, that the 
action of the borax upon the metal cannot be observed. 

Subttaneei intohtble in borax. Reguline metals, alloys, and 
metallic sulphurets. 

The platinum wire is the best support for borax, which melts 
readily in the ring, without being so fusible as to fall from it 
when in the state of a bead. Upon charcoal, botax cannot be 
Fused to a bead without difficulty, and the coloum cannot be so 
conveniently examined as when in beads upon the wire. Many 
metals communicate to borax the same colours as to microcos- 
mic salt — but this is not always the case. The beads of borax, 
like those of microcosmic salt, change colour in the inner and 
outer flame. Several substances give clear beads with borax, 
which remain clear when cold, and even when greatly over- 
charged with matter ; but have neverthelesa the singular pro- 
perty of changing to an opaque enamel, when gently heated, by 
the oxidating flame apphed intermittingly. This mtermitting 
ajiplication of heat is best managed by keeping the oxidating 
ffame quite steady, as exhibited in the figure following on the 
following page, and chan^g.the position of the wire b, by first 

»tl>epniciired.nanulr.Ttli4>,tlioriiui,»ii&iUani,&i!. The 



I Goo'^lc 



TII9I0N WITH BOBAX. 177 

ratdng tho bead half an inch above the point of the flame, then 
bringing it down to the level of the flsme, then sinking it half 
on inch belom the flame; then aft^rirards nuwtg it gradually, 
first to the level, and then up above the Same, and so on alter- 
iiat«ly. 




The production of colours in beads fonned with borax in the 
oxidating flame can aometimea be fiicilitated by the addition of 
saltpetre. A small elender crystal of tbig salt ia supported near 
the lBnip,ason the projection marked din the figure on page 113; 
and when the beaid ia removed from the flame, it is instantly 
pressed upon the crystat of saltpetre. The bead immediately 
swells and fbams, and the oxidised metal exhibits its colour on 
the edges of the froth thus formed. By this expedient a portion 
of manganese so minute as otherwise to pass notice, can be 
readily detected. 

The colours of Beads produced by various metals with borax, 
are exhibited in the Tables at pages 180, 1 81 . 



°— 'Cot^gk- 



COLOURS OF BEADS OF MICROCOSMIC SALT, 



OXIDATING FLAME. 



'Barytea, 
Strontiaii, 

Magneraa, 

Olucina, 

Yttria, 

Thorma, 

ZJTconia, 

Alumina. 

Molybdie 



The whole of these when added in 

excess, produce a glass which ia 

milk-white when cold. 
When carbonates are acted npon, 

they discharge carbonic acid with 

efFcrvescence. 



fcolonr ia greenish, especially 
le hot. It con only be got co- 
leaa on the platinum wire, and 
always that way. 



Towli. «ad JBothaUltUyeUow. 
Antuuonions acid, ) ^ 



f Doea not become opaque when cold. 



tfrom the eartha. 
With an excess, yeUon 



Titanic acid. 

^?' . I An exceaa of these three irfvea a milk- 
J^"™' ( white bead when cold. 



rChromium, Reddiah while hot; green when cold. 
Q^^gj, J Uraninm. Yellow while hot ; green when cold. 

j Copper. Green while hot; blue when cold. 

(^Molybdic acid. Palewhcncold; colourless on the wire. 

Tsilrer / ^^P^^^x^^^^ when a great esoeas is present. 

j ' \ Colour reddiah by caudle light. 

Yellw i Bismuth, i^^f "pearly colourless when cold. 

1 {_A great excess produces an enamel. 

I Vanadium. 

LUranium. Yellow while hot; green when cold. 

^ ,0f these three metala the colour is seen 

\ Cerium. ( best while the bead ia hot. It gets very 
Bed ■< Iron. ■< pale as it cools. The addition of tin to 

/ Nickel, i the bettd containing iron, changes its co- 

^ ^lour to blueiah-^reen. 

Blue Cobalt. 

{The addition of saltpetre assista the 
production of thia colour. The addi- 
tion is made bv pushing the point of 
a small crystid of saltpetre into the 
Aised bead of manganese. 



C0L0UB8 OF BEADS OF MICROCOSMIC SALT, 



REDUCING FLAME. 



Boiytes, 

Btroutian, 

Magnesia, 

Glucina, 

Yttria, 

Thorina, 

Cerii 



Ziiconia, ~] 
Alumin% 

Cadioiaxa, 
Tin. 



a the oxidating flame. 



Red in the oxidating flame. 
Manganese, Violet in the oxidating flame. 
^ rDark blue and opaque vhile hot. 

J \ ducing flame. 

' ^ Chromimn. Same in oxidating fiame. 

V.n.d.^.lBXf^-S.S.'C.''''" "■'''■ 
Uraniimi. Same in oxidating name. 
Ulron. Red in oxidating flame. 

rTungstic acid containing Iron. If tin is added, the 
'l bead becomes blue, or if much 

I iron IB present, green. 

I Antimonions odd containing iron. 

I fThe colour of tliis bead becomes pale as It 

J cooIb. It gJTes the same colour in both 
I Nickel.< ilameB, by which it is diatinruished fixim 
■ iron. If tin is added, it first becomes giey 

[^ I, and opaque, and then colourless. 

{The Dead is opaque. In the oxidating 
flame it is green and tnumtareut. The 
addition of tin promotes the reduction. 
Too much tin precipitates all the copp«r, 
and the bead becomes colourless. 
rtJobalt. Same in both flames. 

rYellowiah white in oxidating flame. 
< TuniMtic acid J ^ '^'' "^ present, red in the reduc- 
V™^"*=""*'-img flame. The addition of tin de- 
I (.stroya the action of the iron. 

LMolybdSc add. Blue when liot ; green when cold. 
I" Yellow while hot. 
Titanic acid.-^ Becomes red and violet as it cools. 

|_ Colourless in oxidating flame. 
fTellurinm- m i ■ . , ,. 

Bismuth ^^leney colour IS owiM to the presence 
J x^ead V i^i^^ed metal. The beads sometunes 

1 Silver ^become clear in consequence of the en- 
Untimonj-* *"* separation of the metals. 



COLOURS OF BBAIffi OF BORAX, 

PBODCOBD IN ISB 

OXIDATING FLAME. 



Strontian. 

Magneoa. 
Glucina. 
Yttijft. 



The saturated beads of these 
twelve BubataDcea, produce ^a- 
que enamels when heated with 
an intennittuig flame. 



Tantallc acid. 
Titanic add. 

Cadmium, 
Silver. 

Alumina. 
Thorina. 



Tellurium. 
Bismuth. 

AnUmony. Yellowish while hot. 

Tungrticocid. { ^ex^^*^^ ^"^ "^^^ " *^' 
f Yellow while hot, or with a great 
Molybdic acid. < excess red wlule hot, and a 
.Tin. t_ blueish enamel when cold. 

T™ . „ fRed while hot; hecomes yellow and 

|_ Copper. Gieen mule not; blue when cold. 

^Vanadium. 

I rOeta pale as It cools. 

< Uranium.-/ With an excess, becomes opaque when 
/ |_ heated with the intermitting flame. 

^Lead. Nearly oolouilesa when cold. 

r f Reddish-yellow while hot; yellow when 

Cerium.-^ cold. Becomes opaque when heated by 

I Ithe intermitting flame. 

^ (3ccomo yellow as they cool, and nearly 

I Iron. _1 colourless when cold. The addition of 
Nickel.J saltpetre makes the Nickel glass blue, but 

L (not the Iron glass. 



Violet Manganese. Appears black with ai 



COLOUBS OF BEADS OF BORAX, 



All these are also without colour 
in the oxidating flame. 



Vanmlinin. 



REDUCING FLAMES. 
"Barytee. 
Stroutian. 

Magnesia. 
Glucina. 
Yttria. 
Zirconia. 
Tantalic Acid. 

Cadmiain. 
Alumina. 
Thorina. 
Silica- 
Tin. 

_^ ( With excesa white and crystalline. 

*''*™™' t Red u» the oxidating flame, 

r Violet in the oxidating flame. 
J The reduced bead acquirea a colour 
(^ if not quickly cooled. 
'Green both hot and cold; but in 
the oxidating flame, it ia red when 
hot, and green when cold. 
Brown while hot, green when cold. 
, Yellow in the oxitbting flame. 
TBlackened by an intermitting reduc- 
< ing flame. ' "' 

(_ Yellow in the oxidating flame. 
"ed in the oxidating flame, 
larker in colour as it cools, red with 
excess, tin renders the glass milky 
when cold. 
^Coloorless in the oxidating flame. 
Titanic acid. Yellow while hot, violet when cold. 
TMolybdic acid. Colourless in the oxidating flame. 
I rOreen in the oxidating flame; me- 

3 tallic tin assists the prodnction 
j of the opaque brown bead. See 
( page 175. 

Same in the oxidating flame, 
r Yellow while hot, violet when cold^ 
1 becomes opaque if heated with the 
Titanic acid. < intermitting flame. Coleurleasin 
I the oxidating flame when hot, but 
[_ white enamel when cold. 
r Antimony. 

I TeUmium. i , . ,. - 

J Nickel. >'" consc-qnencc of the presence of 

I Bismnth. 
LSilver. 



Uranium. 
-Irom 



JTuagBti( 
^Til 



1 Copper. 



Cobalt. 



Ked 

rDar 

icadd.J I 

CCol 



reduced metaL 



I , Google 



DSB or TBK BLOWPIFB. 



MINERALS FOB ANALYSIS. 

As no one can become maater of the blowpipe without a good 
deal of exerciss, and ae materiak for working upon are neces- 
narj for that purpose, I recommend to the reader's notice a 
small Cabinet or Minerals, which may be procured, at the cost 
.of half-a-gainea, from Mesars. Richard Griffin & Co. Glasgow. 
It is known by the title of "Grifdn'h Collbction or Minbiuls 
roB Examination by Experiuent: comprising fifty-four import- 
ant minerals, selected fi-om various cla^s, and adapted to differ- 
ent modes of' Analysis by Chemical Tests and the Blowpipe.' 
The Dames and locahties of the specunens contained in this 
Cabinet are aa follow: — 

. Maonetic Ibon Pteitis, B»- 

. Red Iron Ori, llsfeM, Hrti 
. Specular Irom, IsIb of Elta 
. Brown Iron Ore. Amberg 
Sfathosb Iron, Biber, Hesse 
Clay Ironstone, Wieserl, 
He»e 
. GrET MAHaANISE, Ilefeld, 



lind 

I. PtASTTC Clay, Wiewrt, Hssw ; 
. Amianthus, Sterxliig. lyol 
I. Ctaniti, ZliUrtb&l, Tynil 
>. ToFAl, Bruil 
'. Ai-LOFBANB, Better, Hungaiy 
>. Mica, AsrlieKiiiilKrg, Biie *' 



H»rz 



Tm, 



luid 

!. Schorl, (Black TfrurmaliHe,) 
:. MiSoTrPB, Seiiser Alps, Tyrol 
.. PcTHiCK, Isle nfLipiri 
I. Lefidolite, MnnviR 
>. Calcareous Spar, Iceland 
. BiTTKBSPAB, Zillertlial, Tyrol 
'. Phospuurite, Aniberg,BavirlB 
I, Fluor SfaR, Schrieaheim, Ba- 



. Anhtdhous Gtfsum, 

Wlrtemberg 
■ GtrauH. LunehiB-f, Hanon 
, MaohbSITE, Buidissfra, Pj 



Suli, 



S3. Heav 

!4. CcEi 



I, Schriesheim, Ba- 4 



K Salt, Hall, Wirtemberg 
gp, ALDHiTK, Tolfa, Italy 
27, OniDnLATKD Iron, Arenda], 



Atleubetg, 

Native Bishutb, Schueeberg, 

>. Natu-e ABSEinc, Aiidraasberg 
' "~ LOAR, Kapnib, Huiigsry 

Y Cobalt, Blehei-, Hfsse 
;, ScLPHnRKT OF Nickel, Ebera- 

dorf 
.. Grey Corraa, (Fabkrx), Sie- 

gen 
. Copper Ptrites, Dilleobiirg, 



I, Phosphate of Lead, Hofs- 

gnind, Baden 
I. Zinc Blenos. Han 
. Silicate or Zinc, Siberia 
:. Cinnabar, Mascbe Deux Poota 
I. Sdlfhdr, Bei, Moravia 
;, Anthracite, Ebendorf, Sax- 






i:, Google 



DISTILLATION. 



DISTILLATION. 
As Uie fluid carried off in the atote of vapour, during eva- 
poration, is entirely loBt, being sacrificed for tile sake of the 
nxed substance with which it vras combined, and which re- 
mains behind, that process is onlj employed when the fluid is 
of little value. But, when the fluid is of sufficient consequence 
to be preserved, we have recourse to digtiUalion, which may be 
defined a chemical operation whereby a volatile substance is se- 
parated from leas volatile Bubstauces, and the volatilised portion 
is collected for use. 

Solid sulphur becomes liquid when strongly heated, and if 
raised to the temperature of 6OO0 F. it boilt, behaving in that 
reject as water does at the temperature of 212" F., whereat 
ttu^ liquid changes the fluid for the gaseous state, and instsntly 
expan<& in bulk no less than seventeen hundred timea. Ad- 
mitting sulphur to expand in like manner, if not in like degree, 
a smalt piece of that substance toust be considered to be suffi- 
cient to fill a lai^ vessel with vapour of sulphur, and experiment 
proves this to be toe case. 
For example, when sulphur 
is boiled in a glass retort, a, 
over a spirit lamp, a very 
small quantity of the solid 
substance suffices to fill the 
entire vessel with gaseous sul- 
phur. If a considerable quan- 
tity of sulphur is placed in 
the body of the retort, and 
exposed to beat, gas continu- 
ally rises &om it as the boil- 
ing proceeds. This gas gradu- 
ally forces the atmospheric air out of the retort, and presses 
after it down the neck, c, of the retort. This neck, being be- 
yond the heating influence of the spirit lamp, is kept in a cool 
state by the surrounding air. The consequence of this is, that 
the gaseous sulphur which presses down the neck, soon reaches 
a situation when the temperature is below 230" F. Arrived 
there, it loses its gaseous form, and is deposited upon the glass 
in a fine powder, communicating, as it falls, a certain degree of 
heat to the glass. This production of gas in the body of the re- 
tort, and deposition of powder in its neck, continue till the entire 
retort becomes sufficiently hot to allow the sulphur to fiowA«m 
itfi mouth in the liquid state. The powder previously deposited 
in the neck then melts and runs out. If the beat is continued, 
the whole of the sulphur which was put into the retort is thus 
gradually converted mto gas, and the gas condensed in the neck 
mto a liquid which flows thence into the receiver 6. When the 
sulphur thus distilled has been previously mingled with clay, 
sand, or other substance not susceptible of volatll^tion by heat, 




184 



DISTILLATION. 



such Bobstances renuun in the Tet<»^ after the sulphur has been 
entirely expelled. We see, therefore, in this experiment, in 
what ntanner Babstoncea which differ io their yolatility, and of 
which some are easily raised in vapour by heat, and as easily 
og^n condensed by t»ld, and others not so, in what manner 
such Bubstances can be separated from one another by the opera- 
tion of Dittillalion. 

1 shall here Bhortly describe severel methoda by which this 
Operation ia effected both with small quantities and in the large 
way, premising only, that so &r as the large way is concerned, 
the description here given is not to be considered as full instruc- 
tions for the guidance of practical persons, but simply as a 
theoretical explanation of tne operation for the instruction of 
the chemical 8tudent;^The vessel usually employed for distil- 
lation, in the large way, is called a »tiU. It con^sls of a copper 
Tessel, of the shape of a tea-kettle, but without its spout and 
handle, enclosed in the brick-work of a furnace. Into tne open- 
ing of this vessel, instead of a conmion lid, a capital or moveable 

twisted spirally, and fixed in a wooden tub, so that it may be 
surrounded by cold water. When the apparatus is to be used, 
the liquid intended to be distilled is put mto the body of the 
still, and the head is fixed in its place, the pipe, wbicn termi- 
nates it, being received into the leaden worm. A fire is then 
kindled in the fiimace, and the liquid is made to boil as rapidly 
as possible. It is thns raised into vapour, which passes into the 
womt, is there condensed by the surrounding cold water, and 
flows out of the extremity of the pipe into the vessel placed to 




Google 



PISTILLATION, 185 

The last print very wdl represents the old form of the still 
and its worm-tub, auch as it is at this day to be seen in manj 
distilleries; but other forms have been contrived, both of the 
still and the condensing apparatus, which greatly accelerate the 
operation of distillation, and add considerably to the profits of 
the business. It isproperforme to explain these imprevements, 
not only that you may know the new as well as the old method 
of working, but that you may have an example of the apparently 
•%A( alterations by which a trade of vast extent is often won- 
derfully benefited. 

The first modem improvement upon the still was upon the 
Aape of the boiler, which, instead of being formed upright and. 
narrow, like the body of a tea-kettle, was made more nearly to 
resemble a stew pan, being diminished in height and increased 
in breadth till it exhibited the proportions of the following 



The reason for this change was the proof aflPorded hy eipert- 
ence, that evaporation was effected, with the same expenditure 
of fuel, more rapidly in broad shallow vessels than in deep 

The next improvement made was upon the form of thejEr«- 
olace, which was modified in such a manner as to apply the 
heat produced by the consumption of the fiiel, as directly^and 
as effectnaUy as possible to the boiler. With this view the 
boiler was so placed smid brick-work, above the fire-place, that, 
the flame of tue fuel, after striking directly upon its bottom, was 
forced to rise up on one wde and pass entirely round the body of 
the boiler before it reached the chimney; tne boiler being iup- 
poTted in its place by the resting of a portion of its edge upon 
the brick-work of the fire-place. Fig. 1, is a section of (he 
boiler and fire-place as seen in front, and fig. 2 is a section of 
the same seen Mdeways. The latter also exhibits the direction. 
of the flame, which, dter playing upon the bottom of the boiler, 
passes by e, into the flue that is built round the boiler, and mna 
m the direction c, a, into the chimney b. The advantage of this 
form of the still and fire-place is, that the greatest ev^Knqtioa 



166 PIBTILLATION. 

tokee place in the least apace of time, and with the atAallest ex- 
pense of fuel. 

I now come to describe aa improvement made on the form of 
the head of the still, the apparatus intended to convey the steam 
from the boiler to the condeoBer. In practice, it was found that 
the globular head, shown at ptwe 184, acted in some degree as a 
oondenser, being so much cooled by the surrounding air as to 
re-convert a portion of steam into liquor before it reached that 
part of the pipe which could carry it into the condenser. The 
result of this cooling was that this liquor ran back into the 
boiler, and had to be re-converted into steam, at a fresh ex- 
penditure of time and &iel. This drawback upon the rapidity oi 



the process, was remedied by the adoption of a head, having a 
conical or sugar-loaf shape. The above %ure represents a 
Btill fitted up with the improved head, c, from the summit of 
which a pipe, rf, descends at an acute angle to the condenser, 
e, e, which, in this case, is a perpendicular cylinder, and not a 
worm. The cold-water apparatus, answering to the worm tub, 
is represented here by g, g. The fire-place is at 6, and the 
ash-pit at a. The chunney is seen behind the head. 

The worm-shape, as it may be inferred from the description 
of the last figure, is not etsentiai to the condenser, thougn lis 
occurrence is so common. Any form of vesHel that can be kept 
oool by the continual application of cold water to its outer 
surface, answers the requisites of a condenser; and extremely 
diversified are the forms of vessels that have been contrived 
for this purpose. The last improvement which I shall notice 
on distilling apparatus, is the combination of vessels that ap- 
pears to answer best the purposes of cheap and rapid conden- 
sation. A figure of this apparatus is given in the following 
page. The pipe a leads from the head of the boiler into a close 



vessel, A, fritertninating in the pipe c. This close veBselishoUow. 
It is surrounded by a vegael filled with cold water, «, e, and tile 
hollow within it is occupied by another vessel filled with cold 
water. The fiirm, relative size, and position of these different 
Teesels is shown by the section. There L " ' 

for keeping the vessels always 
fullofcoirf water. Apipe,open 
at bottom, and surmounted by 
a funnel, is fixed in each cold 
water vessel, through which, 
from the stop-cock above, to 
the bottom of each vessel, 
there paases a constant stream 
of cold water; whUe the 
water, which, by condensing 
the steam, has become warm, 
rises spontaneously to the top 
of the cold water, and flows 
gradually oi^t of the vessels 
by the apertures v and /. An 
admirable practical applica- 
tion is made here of the scien- 
tific principle that water be- 
comes light as it becomes 
warm, and the application is 
found to be most profitable in 
the bu^ness we are consider- 



Dfttmpdon q/" a Still adapted for the teparalian of alcohol 
from irtTK*, ajid far use in other analytical inquiries, conf Hueti 

'y Dbsoboisbllks and Gav-Lussac 



Tliis apparatus is com- 
posed of a small cylindri- 
cal copper still, a, about 4 
inches high and 3^ inches 
wide, surmounted by a 
capital, or dome, n, which 
is open at its upper part, 
c. This openmg is in- 
tended to receive the ex- 
tremity, D, of the tube e, 
of which the other end 
forms a worm in the re- 
frigerant, r, and termin- 
ates in an orifice at o, as 
represented in the figures 
in the following page. 





I , Google 



DISTILLATION. 





Connected with this apparatus ore two cylindrical jara on feet 
■iniiln i- to figure n — one of them gradu^ed Into 300 diTimoOHi 
the other into about 130 divisions. These jars should be about 
6 inches high; the loiger 1} ioch wide, the smaller 1^ or 1 inch 
wide. 

In using this still, yon conuneuce hy filling the lar^ jar 
with the nine for analysis up to the division 300. This wine 
jDU poor into the still, to wliich you then adapt the dome s 
and refrigerant f, fixing the tube b in its place at n by means of 
the screw k, which passes through a moveable iron handle that is 
fastened to each side of the still at i, i. The still is placed within 
an iron cylinder, o, and heat is applied by means of a spirit 
lamp, Q, aunilar la that described at page 18. 

liiejar His placed below the refngerant, and serves to collect 



DIBTILLATIOK. 



189 



the alcoholic product of the distillation aa it eacwes from the 

Eipe o. It is neiXMory to be careful, during the distillation, to 
eep the refrigerant supplied with cold water, and continutdljr 
t« wet the cloth which envelopes the tube between s and d. 
The water which drops irom this cloth is collected by the gutter 
p, and carried to the little reservoir at its lower end. 

The distillation is arrested when the product in the jar h 
amounts to 100 divisions, or to one-third in bulk of the wine 
' submitted to anatvais. This distilled product consists of alcohol 
and water, the relative proportions of which are determined by 
taking its specific gravity, either by weighing in a thin bottle or 
by means of the hydrometer. The proportion of alcohol beii^ 
ascertained, the number is divided by 3, to find the per centage 
of alcohol of the wine submitted to analysis. 

Thus, for example, if such an eimeriment yields 100 parta of 
diluted alcohol at 30" of the ceutisunal alcoholiiueter, the rich- 
neas of the wine is =^ 10° — that is to say, it is to be considered 
as containing ten per cent, of alcohoL 

Whenever, through want of attention to the progress of the 
distillation, you happen to collect above 100 measures of product 
in the jar n, you cannot, after ascertaining the alcoholic strength 
of the product, determine that of the wine by simple division of 
the number by 3, as in the case where exactly 100 measures are 
collected. You have, however, still only a very simple calcula- 
tion to go through, to det«Tmiiie the pomt in question. If you 
collect 106 divisions of product, containing 33 per cent, of 
alcohol, yon divide this result by 3, which gives II. This you 
multiply by the number of divisions obtained, namely, 106, 
which gives 116G, and divide this by 100, which gives 11.66. 
This is the per centage of alcohol of the wine. 

DisnixATiOH Of Volatile Oit-a. — Tills little still can 
1)0 also employed in several other operations, as, for 
example, in the preparation of odoriierous waters and 
volatile oils, in tne determination of the quantity of 
alcohol capable of being extracted by distillation from 
a mass of fermented dough, &c. For operations of 
this sort, it is useful to have the little piece of addi- 
tional apparatus represented 
in the margin. It consists 
of a circular disc of brass, a, 
pierced with numerous small 
holes, supported on three 
legs about | of an inch long, 
and having a single rod as 

ra handle on its upper side. 
By means of this handle it 
can be introduced into the 
still. A, or withdrawn at will. The solid substances 
intended to be distilled are placed upon this disc, 



ir 



.CUhi;jIc 



190 DISTILLATION. 

and the whol« apparatna is put together, as before directed, 
for distillation. A quantity of diBtilled water ia next put into 
tlie KToduated pipette, b, whicli is then adjusted in tile opeDing, v, 
of tne dome, b, (pi^fe 187,) by means of the cork, u, fixed on 
the lower point of the pipette, of which the upper extremity ia 
closed by the cork, t. 

The apparatus being thus arranged, the cork, t, is loosened, 
and a small quantity of water ia introduced to the substance to 
be distilled. The cork, t, ia then fixed tisht. Thia wat«r 
reaches the bottom of the still through the tioles in the brass 
disc, B, and being, on the application of heat, converted into 
steam, it ascends and acts upon the substance placed upon the 
disc. Whatever this solid substance cout^ns of alcohol or vola- 
tile oil, is then extracted and carried off by the steam. When 
the first quantity of water applied has passed off in distillation, 
a second portion is added as before, by loosening the cork, t, and 
this ia continued until it is itn^ned that the substance in the 
Still is entirely exhausted of alcohol or of oil. This disposition 
of apparatus has the double advantage of prerenting the bum- 
mg of solid vegetable matter which occurs when it is placed im- 
mediately upon the bottom of a still, and of more completely 
effecting the separation of its volatile parts than it is possible 
to do when the substance is simply boiled in a quantity of water. 

The following is another method of distilling volatile oils, as 
described by Mitbcherlich, in connection with the large still 
figured on page 186. A cylindrical vessel, n,i9 hung in the still; 
__!._. - - 1 . 1-... lay above the bottom of the cyl' "' 
cal Tesaet; and the vegetable 
distilled is placed upon the sieve. 
The edge of this vessel rests on the 
' edge of the still, and ia so arranged 
that it can be screwed air tight to 
the still-head. The flat top of the 
still is provided with a hole, and 
there is another hole in the head of 
the still. Through both of these 
holes the bent tube, 6, passes, and one end of it descends below 
the sieve, c, in the cylindrical vesseL When the water in the 
stiU is boiled, the steam necessarily rises through the pipe, b, 
descends below the sieve, c, and thence rushes through the ve- 
getable substances in its way to the head and the condenser. 
The narrower and longer the vessel a ia made, the more effectu- 
ally is the vegetable substances which are placed in it exposed 
to the solvent action of the current of steam. 

The liquid which flows from the pipe of the i»ndensing ap- 
paratus, in an operation of thia kind, ia a mixture of water and 
oil. These liquors, npon reposure, separate, and the whole of the 
oil swims upon the surface of the water, excepting a certain 
quantity, which is dissolved and retained in solution by th» 




DltTlLI^TION. 191 . 

water— « qnanfity Tariable with difietent Bpedw of oil and at 
difiereut temperatureB. The apparatus nsoaJly emplojed in the 
'"■ -- separation of water from oil ia 

" termed the Florentine receiver. 

It ia represented in the margin. 
A ia a conical bottle, having a 
[ tubnlore, or mouth, b, near the 
bottom. A bent slaas tube, c, is 
fixed in this mouth bv means of 
' a cork, n. During the distilla- 
tion, oil and water flow togethei" 
into the mouth o, of the bottle a. 
Thej gradually separate there, as the mixture coola, and the oil 
rises to the top of the water. When the level of the mixed 
liquids in the vessel a, rises above the height of the tube c, die 
water runs through c till the level in the vessel is reduced to 
the height of c, at which it remains unaltered — water then iasu- 
ing constantly from the pipe c, in proportion as additional fluid 
comes into the vessel at d. The water which thus issues from 
the tube is collected in the vessel e. The widening of the 
vessel A is for the purpose of retaioing the water a auflicieat 
time to allow the oil to separate from it as completely aa possible. 
After all, however, the water thus separated is a saturated 
solution of the oil that has been distilled. When, for example, 
lavender is thus treated, the oil obtained ia oil of laxiender; the 
water thus separated is lavender mater. Nearly all odoriferona 
waters are prepared in this manner for the use of the periiimer 
and the druggist, although it is possible to make them directly 
by mixture of the oils with water. The mixtures termed esprits 
by the perfumers differ irom these scented waters simply in the 
substitution of alcohol for water: etprit de tavande is a solution 
of oil of lavender in diluted alcohol, and so on. In general, these 
eapriU are prepared by distilling the various plants, in the man- 
ner described above, with whisky, gin, or Drandy, instead of 

The following method of separating volatile oils from water 
may be employed where the Florentine receiver is not at hand. 
The mixed liquids are to be received in a cylindrical vessel. 
, When the latter ia nearly full, a syphon is to be used to draw 
off the water. To this end, the long leg of the syphon is put 
into the cylindrical vesecl, and a current is produced by suckinc 
with the mouth at the end of the short leg. The water runs oR 
till the sur&ce of the liquid in the cylindrical vessel descends to 
the level of.the mouth of the short leg of the syphon. The 
current then stops, but in proportion aa fresh mixed liquid ar- 
'. rivea in the vessel from the still, a corresponding proportion of 
water escapes by the outer leg of the syphon. , 

A third species of receiver, adapted for this purpose, is a stone 
jar, having a mouth at the top, in the manner of a greybeard, 
and another mouth at the side, near the bottom, to which a tube 



' 193 DISTUiATtON. 

can be atdMusted in the same nuumer m to the Florentine re- 
ceiver. Two-necked jois of this description, and which, as ore 
to be shown presently, are lueful for aupplying a stream of 
water, and other purposes, are now to be had in Qlasgow at a 
very moderate price. The price of a jar of one quart capacity 
ials. 

DrniLLATioN IN Retohts. — The common still, in all the fbre- 
gcang varietiee, can only be employed in the laive way, or in 
ue oislillatioa of such liquors as do not suffer injury from the 
copper, tin, lead, or other metal which enter into the construc- 
tion of the still or cooler. The vessel which is most employed 
by the philosophical chemist in the operation of distillation, is 
the retort. This is a pear-shaped vessel of glass, aJT"'!"'' in form 
to the figure given below. In the top of the body, or wide part, 
is an opening, or tabulure, through which the materials to be 
distilled arc inserted. This opening can be closed by a cork 
or by a glass stopple, ground so as to be tur-tight. Retorta are 
aometimes made without the opening at the top, as is that figured 
in the description of the distillation of sulphur, page 183. They 
are then cheaper, and are called plain retorts; but those with 
the opening, called tiilntlated retorts, are, in some cases, more 
convenient, though they are liable to the inconvenience of 
cracking at the tubulure, especially when the latter is put on 
clnroffily, like a thick lump of glass. Retorts are also made of 
porcelam and of platinum. 

A necessary appendage 
to the retort, is a receiver. 
The retort ia the vessel in 
which a liquid is raised 
' " I vapour. The re- 
er is the ve»el in 
which the vapour is again 
condensed into the liquid 
state. The receiver is a 
vessel of glass, generally 
of a globular form, though not always so. The annexed iieure 
represents a tubulated retort, connected with a tubulated re- 
ceiver. The tubulure of each of these vessels is represented as 
being stopped with a cork provided with a riaas tube. Some- 
times the neck of the retort is much too small to fit closely the 
neck of the receiver In that case, a cork must be provided 
that fits the latter, and must have a hole burned or boreothrough 
it, of a sufficient size, to hold the former. The pi* with a cork 
will not answer, however, when corrosive fluids are distilled. 




t then use an instrument of glass, called an Adapter. 
This consists of a glass tube, shaped like a rolling-pin, one end 
of which takes in the mouth of the retort, and the other end of 
which goes into tlie month of the receiver. The joinings are 
secured by cement, 

,. ,„Goo;,lc 



Disnu^TioH. 193 

Sam OF Oh^BB Retorts.— The sizea of retorts most generally 
useful to ft student are those of 2, 3, 4, and 8 oz. capacity, and 
fot occasional use, one that holds a pint. The 2 oz. and 4 oz. 
plain and tubulated are to be preferred. They answer best 
when made of hard glasa, but nint glass can nevertheless be 
used, excepting in dry distJUationa for the preparation of gases, 
&c., for which pnrpoaea hard glasa is indispensable. In such 
operations, it is ui general most advisable to ose veiy small dis- 
tuling Teasels. The little tube vessels described at pages 8 — 10, 
serre both p6 retorts and receivers, in a great nuracieF of cases ; 
and the student who can use the blowpipe, is able to modify 
their forms with bcility. 

The simplest of all such minate re- 
torts and receivers are those formed of 
small tubes without bulbs, which can 
be set together in the manner shown 
by the figure. They aie extremely 
useful in small experiments. The bent 
tube is, of course, the retort, and the 
straight wide tube the receiver. 

In some cases the retort answers 
best when made of the annexed ferm, 
etppecially when the purpose to be 
effected is a dry distOlation. 

The annexed figure exhibits another 
form of distillinx apparatus, which may 
be employed when small quantities ot 
substances are operated upon. It con- 
aista of two am^l bulbs, blown out of 
a glass tube by means of the blow- 
retort, and the other for a receiver, and 
ly a narrow glass tube. 

Here is another apparatus of like 
kind, a is the retort, b a receiver 
formed of glass tube, e a vessel of cold 
water, acting the part of a worm-tub. 
It is easy to connect a to 6 loosely, by 
a isork or a fold of paper, tf is the flame 
of a spirit-lamp. 

Aa the operator's command of heat is always ver^ great in 
respect to these small retorts, the economical' considerationa 
which are of so much importance in reference to the form of 
the sHtl, are in tbis case of no consequence. That form of small 
retort is best, which is easiest to make and easiest to clean ; 
which most readily permits the insertion of the chai^, and can 
be best connected with the condenser. 



C==^ 




I , Google 




I)imi.LATIOK. 

In many caste, a flask can be etn- 
ploved, instead of the retort, as a dis- 
lillmg Tesael, connecting it with the 
receiver, by means of a bnit giaes tabe. 
The figuTD in the maigin exhibtia a 
piece of tube of the size Eind atrength 
commonly employed in operations of 
this nature, and which is paned through 
a perforated cork of the size necesaaiy 
to fit the month of an ordinary flask. 
Thra species of tube is very mnch 
employed in the conveyance of gate»f 
from the veseeb in which they are ge- 
nerated into those prepaied wc their 
reception. 



Porcelain ttEToais. — For certain experiments, which requirQ 
a high temperature, retorts of porcelain are required. Thoee 
of the best quality are mode at Beriin. They are longh-on the 
outside, but glazed within. There are three sizes in common use, 
the prices of which in Olaagow are as follows : — 

No. 1, — 7 inchei long, 3b. pl&ln, — 4<. tubuUted. 
8,-9 . -- - 



3,-16 



do. 



. — 10i.6d. 



In general the operatbns for which these porcelain retorts are 
used, require so high a temperature that the aid of a fomace is 
necessary. The heat requires to be raised gradually to prevent 
the qilitting of the retort, and it should be as gradually reduced. 
The Berlin porcelain retorts will, howerer, undergo without in- 
jury such cnanges of temperature as immediately dortroy any 
other variety ofporcel^n. 

Retort and Receivbk ooubined. — The annexed figure exhibits 
the bent tube employed by 
Dr FiRADAT, to supply the 
place both <xf retort and re- 
ceiver. When a liquid is 
boiled at the bottom a, the 
vapour it produces can be 
condensed at the bend i, by 
the external application of cold water, while incondensable gases 
escape at the mouth e. Such a vessel is useAil in efiecting the 
solution of substances which dissolve with difficulty, and which 
require to be frequently redistilled with the sameliquid, of which 
substances platinum affords an example. If that metal is boiled 
in an open flask with aqna regia, a great loss of acid is sustained 
before the solution of the metal is effected; while, by using this 
bent tube for the operstion, the volatile add can be retained, 



DifiTILLATtON. 195 

Knd from time to time be returned upon the metal by a slight 
iuavement of the vessel. 

As to the way of using this little piece of apparatus in dis- 
JiUatton, I cannot do better than describe it in tac worda of Di 
Fakadat> ^See Chemical Manipulatiim, page 396.) 

" The fluid to be purified or distilled may be poured into the 
tube ; and the latter bein^ held upright, and the finger placed 
ever the aperture, heat should be applied below, aod vapour 
raised : tiiis will condense upon the udes of the tube, and flow 
down, carrying with it that portion of the fluid which, in pour- 
mg it in, adhered to the aide ; this should be done till it is ob- 
served that the vafoOT rises nearly to the top before it condenses, 
and insures the cleansing of the whole tube. This preliminary 
operation is intended simply to wash the adhering portion of the 
introduced fluid to the bottom of the apparatus, that nothing 
may remain at b to contaminate the distilled products. The 
tube is then to be placed as in the figore, the proportion of the 
Teasel and the charee being mch, that the latter should not oc- 
cupy more than half that part of the tube (from a to the first 
bend). Heat being then gradually ^plied near the top of the 
liquid, tbe latter should be distifled over into the angle at 6, 
which is now to be cooled by wet paper, water, or some other 
means. If. the distillation be nosatis&ctory, it is easy to return 
the product, and repeat the operation.'' 

Insb&tioh of the Charoe into a R^TottT. — The substances 
which are to be subjected to distillation should be put into the 
retort with care. When it has a tubulure, they are to be in- 
serted thereby. Solid bodies ought not to be dropped in so 
as to fall suddenly upon the bottom of the retort, otlierwise they 
will make a hole and faU through. The retort should be in- 
clined, and the pieces, reduced to a small size, be allowed to slide 
in gently. If there is no tubulure, care should be taken, in plac- 
ing the charee in the retort, not to soil the neck, otherwise the 
vapour which rises during the distillation, and wa^es the neck of 
the retort, will convey the impurities into the receiver. If the 
neck of the retort is first made very clean and diy, solid sub- 
stances may be passed in without soiling it ; powdcTS should be 
dried before the fire and then poured through a dry and warm 
funnel ; liquids ought to be inserted by a funnel, having a glass 
tube neck snfSciently long to reach into the body of the retort, 
and at the same time to project beyond its mouth. When a 
liquid has been poured through such a funnel into a retort, the 
iunoel should he carefully withdrawn, and in such a 



manned by holding the retort in such a position that the ojien- 
ing of its neck is brought ratlker lower than the part which joins 
the body of the retort. The drop then runs back into the neck 
of the Annel. 



196 mmuuTioM. 

The eluige jnit into a retort ought Mldom to ooenpy above 

one-tliird of its capacity. When a greater propoTtioi) or materj- 
tia ix inserted, the msas ia liable to boil OTer. 

For farther instmctioDs on this subject, see pages IS and lOS, 
where I have already f^okeii of the precantions neceasaty to be 
taken in putting charges into glass vessels. 

Applioation of Hbat to RBTosn. — The heat applied to a glan 
retortinay be that of a spirit lamp, a gas light, or a charcoal fire. 
When the retort is small, and only a moderate degree of heat is 
required, the retort may be snpported over a spirit lamp by means 
of the triangular retort-holder described at p^e 37, or still bet- 
ter by means of the flat ring of the lamp furnace, paw 24. In 
general it is advisable to pnt between the retort and the flame a 
thin stratum of sand contained in a, sand bath, which may either 
be a capsule of copper or of ironstone, of which description two 
sizes are now mode in Glasgow as accompaniments to the lamp 
furnace. Another addition to the apparatus last named, and 
specially provided for the operation of diBtillBtion, is an irmiftoite 
dome, adapted to the top of the lamp furnace, and intended to 
perform the same good ofiice of retaining heat about retorts, that 
the dome, d, figured at page 24, performs towards flasks. This 
new dome resembles a oee-bive, vrith a large door ; and when 
placed upon the lsmpftimace,it corers the whole upper part of 
the retort, excepting the neck ; and by keeping the retort warm, 
pierents the condensatbn of vapour before it fairly entws into 

The advantage derived from the use of such a dome is evident, 
if we consider that in distiUations of this sort it is of importance 
that no condensation takes place in the upper part of the retort, 
and that the retort be so snaped that whenever condensation 
begins, the resulting liquid mav flow into the receiver, and not 
retnm into the retort. If the latter occurs, the fuel is spent in 
run, and the operation may last for weeks, as the result of the 
distillation is then merely a circulation between the upper part 
of the retort and the lower. The first wood cut that fbllowB this 
parsgraph shows the best form for a retort to be used in distillft- 
lion over a lamp. Where the stoneware dome which 1 have 
described, cannot be procured, a cone of pasteboard cut nearly 
to the shape of the upper part of the retort, but somowiiflt larger, 
and filed above the retort during the operation, may supply its 
place. 1 have in another section (page 30) described a similar 
contrivance for this purpose. 

Of the two sand baths that I have alluded to, the smaller is 
adapted for the orifice of the ring-top, c, of the lamp furnace, 
page 24, and can be used with retorts of 4 oe. capacity. The 
larger is adapted to fit the top of the furnace cylinder, b, pag^ 
24, without the ring, and to receive retorts of 4 oz. to 12 oz. ca- 
pacity. When this sand bath is used, the edges of the dome 
resta upon the sand within the capsule. 



DISmXATIOH. 197 

In some cases, the retort is best held by the neck, instead of 
beiag supported below. The tube holder (page 43) is adapted 
to support retorts of one or two ounces capacity; and Sefstroem's 
holder (page 39), to support larger vesscla. When the retort 
ia large, tt may be exposed to the heat of a charcoal fire, or to a 
sand heat, by means of Luhme's furnace (page 291. If a furnace 
b not at conunand, a large gas fiame (page 28), or the large 
qpirit lamp (page 19), may answer the purpose. 

Best iiK4I«, ow BrrECTiNa Condensation. — In order that the 
T^iDur produced in a distHlation may be condensed as fast 
as it comes over from the retort, the body of the receiver 
attached to the retort is either placed in a tub of cold 
vater, or kept cool by the continually renewed application 
of wet dotha or wet blotting paper. It can also be kept cool by 
meauB of a small stream of cold water, so contrived as to ran 
continually from the point of a little glass syphon placed in a 
pan of water. A remgerant of this description is shown in the 
following figure^ where a and b represent a retort and receiver, 




•B a funnel holder, d a fbnnel with a atop co<Jc affixed to its neck, 
and c a ha^n. The receiver b is coveKd with a linen cloth, or 
what answers bettor, a nett thrown loosely together. The stop 
cock is only so Sea turned on as to allow a very small stream of 
wator to flow out When a stop cock is not at hand, the flow 
of water may be regulatod by merely patting a paper filter into 
the funnel, and letting the water pass through the filter, or by 
partially obstructing the neck of the funnel by means of a cork. 
When the bamn o is too fiill of water, a portion can be removed 
by a syphon. In some cosea it b advantageous to enclose the 
receiver entirely in the nett, as is shown in the following cut. 
The water soffn^d to foil upon its upper part is then very cS^ 



198 DISTILLATION. 

inally spread over its whole sor&ce, and effects a complete 



Theb«3t reirigerant yet contrived for use in amall operations, 
ia probably the one shown in the following figure : — 




a, K, is a tube of glass about 30 inches long, and § inch wide. 
The upper end is widening to admit the neck of a retort ; the 
lower end drawn out to a narrow orifice, b b ia a, thin braas 
tube, 20 inches long, and about 1 J inch wide, fastened upon the 
glass tube by a cork at each end. c is a funnel with a long braas 
neck, communicating with the large tube b b at the lower 
end. tl ia a brass pipe communicating with the large tube bb at 
the under side of the upper end. / is a hollow brass pillar 
screwed upon a mahogoDy foot. « is a brass rod that slides in 
the pillar/, and can be fixed at any height by the screw attached 
to the pillar. A brass band passes round the middle of the tube 
6 6, and is connected with the rod e bya joint g, so contrived as 
to allow the tube fr 6 to be placed at will more or less horizon- 
t illy or vertically. 

When water is poured into the funnel e, it runs through the 



siertu^TioN. 



199 




iqiparatiis iDthedLrectione,b,&,d^aiidtfaenes(»pe8. Initeposmgc 
it wets the entire Hurface of the eocloged glass tube from bU> b, 
CoiiBeg;iiently, if the tipper end of the tube a a is connected with 
a retort, and a stream of cold water is pcMed continoallr into the 
funnel c, rapid condeDsation takes place within the glass tube, 
and the liqnid product of the condensation flows out at the lower 
end of the tube. 

Although two or three methods of supplying a stream of cold 
water have been already noticed, 1 have yet to describe another 
method peculiarly adapted for use with thia refrigerant, a is a 
large and strong glass water flask, S inches 
wide and 6 inches high, exclnsive of the 
neck e. b is a atop cock fixed by meana of 
a cork into a hole drilled in the side of the 
flask near the bottom, d is a strong wooden 
support for the flask, conaiating of a hoDow 
pillar, and a rod surmounted by a small 
table. 

Upon comparing the last two figores to- 
gether, it will be seen that it is easy t« ad~ 
jnat the two parts of the apparatns accurately 
to one anotlier, so as to make the entire in- 
atmment a most effectual refrigerant. 

The glass bottle a, of this apparatus, may 
be advant^eoiisly replaced by a stoneware 
bottle of the form commonly used in this 

I country, for the conveyance and preservation 

~~\f ^ of galfons or half gallons of spirits. I have 

recently bad a quantity of vesaels of this de- 
scription prepared in Glasgow with an extra month, as figured 
in the article " Phosphoric Acid," for the insertion of a stop- 
cock. They are also furnished with a handle for more con- 
venient use. A bottle of this sort, of the capacity of one impe- 
rial quart, coats Is. A brass atop-cock, fiir regulating the supply 
of water, costs Is. 6d, 

The usehlneas of this species of condensing apparatus has in- 
duced me to make some attempts to render it cheaper than it 
can be when constructed in agreement with the description 
given above. The simplest and cheapest of the modified con- 
densers which I have yet constructed consists of a cylindrical 



!« 



y- 



JR. 



tube of japanned tinplate, 
ameter, through which [ 
diameter, and sufficientl; 
c, and 4 or 5 inches at 



I b, 10 inches long, and 1 inch in di 
, jes a glass tube, c d, half-aa-inch in 
ilylong to project 1 inch at the upper end^ 
the lower end, d. This glass tube is fixed 

„H,glc 



200 ■ dibtiujitiok. 

into the tin tube by two corka, a and b. The cork at the lower 
end 15 perforated in the centre. That at the npper end ia bored 
with two holes, as shown at e, the larger of wMch ia intended to 
fit the npper end of the ffhtss tube, c. . When you wish to use 
this apparatus, you pnt &e point of a funnel into the small hole 
in the cork, e, and fill the lai^ tube with cold water. You 
then fix the tube in a diagonal position, as represented by the 
cut on page 198, byadjiiBting the tube,/, soldered to the Bide of 
the larg« tube, and at r^ht angles to it, upon the tube, i, pag« ■ 
42, of the tube holder, by the intermediation of a small slip of 
^eet Indian rubber; that is to say, you fold the piece of rumier 
around the tube, ft, push the tube, /, over it, and then turn it 
round into the proper position. This apparatus can only be used 
in the distillation of very sm&Il quantities, because there is no 
oontriranco for changing the condensing water, and the appara- 
tus is useless when the condensing water becomes warm. It can, 
however, be used in all cases where the quantity of liquid to be 
distilled ia not more than a cubic inch, and where the loss of a 
small quantity of the liquid by evaporation is of no consequence ; 
in other words, it can be used in the preparation of small quan- 
tities of volatile acids, &c., for letting, where purity is required, 
or where particular facts have to be proven, and where so small 
a quantity suffices as can be condensed by the water which fills 
this apparatus once. 

A little retort, which answers very well for use with this con- 
denser, ia represented in its full uze in the following figure. It 




is best when made of Qermon glass; but green glass, or filnt 
^aas, may be used instead. The nock should fit the upper end 
of the g\£m tube of the condenser, as a stmiper fits a bottle. If 
it is much smaller, the two should be fitted together by means of 
a perforated cork. All the vapour which such a retort can give 
over, the small condenser can convert into liquid. 

When the distillation is finished, the condensing water must 
be shaken from the apparatus through the sm^ hole iu the 
cork, e, and the glaa tube, c d, must be washed clean. If the 



iManuATioN. 



condenfflng water ia allowed to remam in the apparatna, it 
qieedily produces ruat. 

The next form of the condenaing' ^panttua, which 1 have 
tried, is represented in the following figure : — 




c b a tinplate tube, 17 inches long and 2 inches wide, a 6 is a 
glass tube, nearly an inch wide and 25 inches long, f g are two 
narrow tinplate tubes, communicating- with the largo tnbe, and 
intended respectiyely to supply the places of the two tubes, c d, 
in the apparatus depicted on page 198. (j is a strong rod of 
wood or iron, forming part of a retort-stand, e ia a tube of tin- 
plate, 1 inch in diameter and IJ inch long, soldered, in the di- 
rection shown by the figure, across the large tinplate tube, and 
adapted, by means of a perforated cork, to the rod, d. This 
support permits the apparatus to be raised or lowered upon the 
rod d, or turned round about it, but does not permit of alteration 
of the angle at which the tube rests in reference to the upright 
rod and the table. 1 giie this very simple form of the large 
condenser, because it is one which a chemist can very easily get 
made in any village where there is a tinsmith. But it is a less 
convenient piece of apparatus for laboratory service than that 
which I have to descnbe next. 




a b is a tube of tinplate 2 inches wide and 17 inches long, c is 
a narrow leaden pipe which passes along the inside of the wide 
tnbe to within an inch of eacn extremity, ia left therein open at 
the lower end, but paesea through the wide tube near the upper 
end, and terminates there in a small funnel, e is a piece of si- 
milar lead pipe, which enters the upper side of the wide tube 



202 DISTILLATION. 

close to iphere the other pipe conies ont, and hangs down an inch 
or two below the wide tube. This short tube is, like the other, 
open at both ends. The whole of this apparatus is japanned 
both inside and outside, and in this state it is sold for 4s. 

When fitted for use, a glass tube, 2S inches in length, is fast- 
ened into the middle of it by means of corks fixed at a and b, 
and bored so as to fit the glass tube water-tight. The glass tube 
answers best when it is conical, being about an inch wide at the 
upper end, and rather less than hau-an-inch at the lower end. 
Tne upper end shonld be bordered or provided with a rim, so as 
to permit the insertion of a cork without danger of fracturine it. 
The lower end may be melted smooth, but should not be bor- 

The tnbe o, in this apparatus is put iMthin the lai^ tube to 
render the apparatus more handy. The tube e enters the upper 
instead of the under side of the large tube, in order to keep the 
enclosed glass tube the more completely covered with cold water, 
especially at the upper end, where rapid condensation is of im- 
portance, as it prevents too much pressure within the retort. 

Nothing answers better to hold up this apparatus than such 
a support as that of Seistroem, described at yage 39, a modifica- 
tion of which is represented below. This holder is strong and 
BubstantiaL It can support any long or large vessel such as the 
condenser, of many pounds weight, at any height within 18 
biches above the table, and in any requisite position. The price 
of this holder, made of white wood, is 6s. 6a. 



^ 



In dirtilling with a condenser of this description, it is neces- 
sarv, in experiments upon exact quantities, to be very particular 
to keep the water in the tube constantly cold, which is effected 
by permitting a small stream of cold water to flow continually 
into the funnel, and placing a vessel below the pipe, e, to receive 



the ejected warm water. But in many common operatioug, aa 

in the distiUation of water, it ia only necessary to chanee the 
WBter in the condenser occasionally, for even when Ihree-wurths 
of the length of the condenser feels warm on the outside, it still 
gives out water at the end of the tuhe nearly in a cold state. 

The distilled product can, in general, he conveniently collected 
at the end of the condensing pipe, by bringing over it a long- 
necked flask. 

I shall only add here, that 1 am now endeavouring to prepare 
both a retort (or still) and a condensing apparatos, of the some 
stoneware of which the lamp furnace (page 24) is composed, 
and which I expect will prove to be useful m the distillation of 
water, the purification of muriatic acid, and in many umilaT 
operations. If possible, 1 shall give an account of this apparatus 
in a subsequent part of the present Tolnme. 

Distillation of Oil of Vitbiol, — One of the most difficult dis- 
tillations to perform In a glass retort is that of oil of vitriol, for 
which reason 1 shall state, in detail, a method by which it can 
be effected. The causes of the difficulty eicperienced are, first, 
that this add has a ve^ low degree of volatiCty ; secondly, that 
it contains sulphate of lead in solution, which falls to the bottom 
of the vessel as the distillation proceeds, and ibrms a maas at 
which the boiling goes on in fits and starts with such explosive 
violence as either to shatter the retort or to drive the acid over 
into the receiver by its mechanical power. As it is, however, of 
great importance to be provided vnth pure sulphuric acid, it is 
absolutely necessary to compass its distillation. The following 
is the method reconunended by Bebzkuub. 




A low broad cone of sheet iron, with ite point cut off, a, is 
placed upon a hearth. A retort is chosen, the body of which 
fits the hole in the top of the cone, when about a tlurd part of 
the retort is passed torough the hole. Sand is put round the 
outer edge of the cone to hinder air from getting m below ; and 
a row of brick^ b s, is then placed round about it. A similar 
cone of sheet iron, but not naving the point cut off, is hung 
above the retort at the distance of half an inch. The retort is 
half filled with oil of vitriol, it is placed in the position above 
repreaented, and the neck is supported by a tile, f f. A chap- 

.oogic 



304 DISTILLATION. 

coal fire is then mode upon the under cone, within the bricka 
X B, and is csrefnlly sustained. After some time the acid in 
the upper part of the retort begins to Ixiil, without bumping, 
and as the overhanging oone keeps the fop of the retort hot, the 
volatilised acid does not condense beibre it reaches the neck, 
from the point of which the drops of distilled acid fbUow each 
other BO rapidly, that if the fire is properly attended to, it ia 
poEdble to distili a Ih. of oil of vitriol by this process in an hour 
and a half. The sulphate of lead deposited during the distilla- 
tion sinks to the bottom, of the retort, where it is out of contact 
with the hottest parts of the glaaa, and consequently produces 

The receiver devoted to the reception of the distilled acid 
roust be of thin glass, and the point of the retort must reach to 
the middle of the globe, in order that the drops of hot acid may 
not full npoD the glass but into the acid already contained in 
the receiver. These precautions are necessary to prerent the 
fracture of the receiver by the great heat communicated by the 
condensed acid. 

No cold water is to be applied externally to the receiver b 
which distilled oil of vitriol is collected. 

Another method of distilling oil of vitriol is described by Beb- 
ZBLins as follows: — The acid is diluted with water till the sul- 
phate of lead, which is insoluble in diluted sulphuric acid, pre- 
cipitates. The diluted acid is then concentrated by evaporation 
in a platinum capsule, after which it is put into a retort and 
distilled in the sand bath of Luhine's fiu^ce (page 30,) being 
protected from the air by a jacket or dome. 

Small quantities of oil of vitriol can be distilled in sm^ glass 
retorts over the lamp furnace, a long and thin glass tube, ter- 
minatiiig in a Florence flask, being loosely attached to the neck 
of the retort. 

In a diatUlation performed on the latter plan, the occurrence 
of explo^ve ahocks in the retort is much hindered by putting 
several crooked pieces of platinum wire into the retort with the 
acid. The boiling then goes on quietly, and the acid produced 
by the distillation ia perfectly pure. 

This power of feciutating the distillation of sulphuric add by 
the insertion of pieces of platinum wire, depends upon the 
general feet that rough and pointed bodies, placed in any liquid 
which is afterwards either warmed or ireed from atmospheric 
pressure, have the ^^perty to originate and promote the disen- 
gagement of gas. This power ia exhibited in the following ei- 
periment. 

A long platinum wire is twisted into a coil at the end and is 
ignited, so as to produce a clean and estensive surfiice. A flask 
is half filled witQ water that has become aatarated with atmos- 
pheric air by long exposure to it. The coil of wire is placed in 
the water, and the latter ia dowly warmed. The atmospheric 
ur, which is insoluble in warm water, thm assames the gaseous 



lASES. 205 

state, and appears in bubbles upon the platinum ^Ti^e■ If now 
the heat is increased till the water in the flask 
gently boils, the bubbles of Hteam produced will 
not appear, as usual, at the bottom of the flask, 
but fie formed round the platinum wire. This 
phenomenon is still more distinctly and elegantly 
exhibited when nitric acid (sp. gr. I'42), or sul- 
phuric acid, is boiled— these liquids can be kept 
boiling round a platinum wire for hours together, 
without the production of a single bubble of gas 
at the bottom of the liquid. As, under equal 
pressures, the boiling of liquids depends upon 
their temperature, it follows, from this experi- 
ment, that the temperature of vapours which are 
disengaged by platinum wire must be lower than 
vapours disengaged from the same liquors when 
heated without the wire. Consequently, the in- 
sertion of platinum wire into liquids, enables them 
to boil at lower temperatures. It overcomes also 
the attraction between the liquid and the solid material of the 
vessel which tends to produce that singular accumulation of 
intensely hot liquor in contact with the bottom of the glass, to 
which ue explosions that occur during the boiling of sulphuric 
acid must he attributed. 



^^ ..v,«™ — easy to extend the account of distillation far be- 
yond the limits which I have here assigned to it; but a" ' "■"" 



It would be I 



youu me iimiis wiucu i uave uere aasigueu lu ii; uuc oa i sutui 

nave to enter into many details in giving instructions for the 
preparation of various volatile chemical compounds, I do not 
think it necessary to enter now into those mmutiee, inasmuch 
as it would produce needless and not very entertaining repeti- 
tions. 



MANAGEMENT OF GASES. 

Fon performing experiments with gases, many articles of ap- 
paratus, not hitherto described, are necessary. These consist, 
partly of vessels for eontajnine the materials which afford the 
gases, and partly of vessels adapted to contain the gases and 
submit them to experiments. Some gases are procurable by 
the mere mixture of the substances, which, upon combining, 
evolve thorn; but others cannot be obtained without submitting 
the materiab to heat. For these different modes of proceeding, 
it is requisite to employ a diversity of vessels. 



206 HANAQBUBNT or OASBS. 

For the gaaea which are piepared with the aid of heat, yoa 
may employ a retort, a Florence flask, or any other glass venel, 

ithe bottom of which is toin enough to bear 
the appUcation of heat without crackiag. 
The Bame resels may be employed for Uie 
, preparation of such eases as do not require 
the aid of heat; but m general the lattercan 
be more readily preparad in veaselg which 
stand steadily npon the table without mp~ 
port. Such a Tessel is the Wonif^s lotOe, 
exhibited by the annexed figure. It is sim- 
ply a broad short glasa bottle, fomiohed with 
two necks. When very small quantities of eases are to be 
prepared, the operations may take place in muSl bottles of the 
'^\ description figured in page 11, or in little 

}^^^ matresees and retorts constnicted of glass 

S ^s. tubes (pages 10, 193.) Oxygen gas is some- 

y times prepared in an iron retort, and hydro- 

'"'"^ fluoric acid gaa in a platinnm or leaden re- 

tort; hot glass is the material which is gene- 
rally made useof fw retorts 

A very small qnanti^ of a gas can also be 
preparea in anch a tube retort as is figured 
below. This consists of a HtraJght dosed 

^-. -^ tube, the mouth of which is stopped by a 

cork, through which is passed a tube lor conducting gas. 




The wide tube may be 4 inches long, and of the width shown 
by the larger of the following figures. Hie condncting tube 
may be as wide as the smaller of the two 
. figures. The wide tube should be made of 
\ hard German glass. The narrow tnbe may 
■« of flint glass. This ^paratus is ver^ use- 
ul in the preparation tn Email quantities of 
pure oxygen gas. 



Omay 
figui 



UAMAOBMXHT OP OASKfl, 207 

When Tou need to ascertain the nature of a gas giYen ont in 
B particular operatioQ, a tube like the following may be em- 

E loved. This tube Bhould bulge out a 
ttle at the elbow, aud the part which 
bnlgea out should be below the sealed 
end of the tube. If you put BOiae muri- 
atic acid into auch a tnbe, then hold it in 
the poaitkiii shown by the figure, and 
drop a bit of marble into it, tlie marble will descend to the 
bulge, where it will be decomposed by the muriatic acid, and a 
quantity of carbonic acid gas will be produced, all of which will 
ascend m bubbles to the sealed end of the tube, and none will 
wcape. In this case, a single tube acts the double pul of a re- 
tort and a receiver. This apparatus is sometimes more ngefiil, 
when the sealed end is turned over a little, made into a month, 
and provided with a stopper. 

Previous to the exaniuiation of a gas collected in this maaner, 
it is often necessary to replace the acid in the tube by water. 
To do this, you close the open end of the tube with your thumb, 
plunge it into water, and then remove your thumb and elevate 
the dosed end of the tube, so aa to allow the denser acid to run 
down, and the water to ascend and supply ita place. 

It is in moat cases egaential to the form of a bottle in which 
gas is to be made, that ita mouth has a spreading tip, so that a 
cork can be readily fixed into it air tight. It is equally essen- 
tial that the neck of the bottle be either quite cylindrical, or 
else wider just at the month than it is a little way within it ; 
for if, as in many cases, the neck of the bottle gradually ffets 
narrower towards the mouth, so that the diameter there is less 
than at any other part of the neck, it is nearly impossible to 
adf^t a cork to it air t%ht, and consequently it is impossible to 
convey the gas thenoe to the place where it is required. There 
is no difGcnUv in procuring a bottle with a good mouth when 
the bottom of the bottle is allowed to be thick ; but it is im- 
possible to procure thin flint glaas flasks with turned lips, be- 
cause they cannot be made with turned lips, unlesa we submit 
to have a thick lump of glass left by the punty at the bottom 
of the flask, exactly in the place where it is certain to cause the 
glass to split the first time it is put over the lamp. This, 
however, is not the case with bottles made of crown glass, which 
are prohibited to be made in this country, but which can be 
procured from Gtermony, perfectly thin at tiie bottom, to admit 
of the ^plication of neirt, and yet with well formed mouths 
for the reception <^ corks. 

MbTEOD of PaoOEKDlNO TO HAEB A GaB. 

Put into the gas bottle the materials whose re-action is to pro- 
duce the deurea gas. Break the solid part into small pieces to 
facilitate chemical action ; put in the powder through a warm 
f^umel, and pour in the liquid through a Ainnel, to avoid soiling 




208 HANAOKMBNT or OASSS. 

the neck of the bottle. If your bottle has two necks, one of 

— them should be provided witli a 

ground glasa stopper, or a cork that 
fita close. The neck through which 
f the gas is to escape, should he clos- 
ed by a cork provided with a glass 
^ tube, bent more or less, accord- 
ing to the distance and shape of the 
vessels into which the gas is to be 
conveyed. The sort of tubes neces- 
sary to be employed in tbeae expe- 
riments, is of soft flint ^hias, because 
that kind is most easily bent idto 
the desired form. The size of the 
~ tube must depend upon the qnan- 

tity of gas that is to be conveyed; a wider tube being necessary 
where a large mass of materials is set to work at once, than where 
only a small quantity isemployed. According to circumstances 
tubes of the following sizes may be employed: — 

o o o O 

The point of a tube which is to deliver gas, should always be 
sli^tly turned up. It &ciKtatefi the discharge of the gas. 

When the conducting tube is fixed into the bottle, apply your 
month to the open end of the tube, and *«c/c strongly : yoa will 
thus ascertain whether or not the joinings of the apparatus are 
completely air tight, and if not, they must he made so. You will, of 
course, make thw trial when the bottle is empty, and not while 
a gas is being generated within it. If the joinings are not air 
tight, they may sometimes he rendered so by applying a small 
quantity of a cement; but it is better to fit new and sound corks 
on the tubes. The corks should be first perforated by the me- 
thod described in the section on " Cork Boring." 

The materials pnt into a bottle to produce a gas, must never 
exceed in bulk the third or fourth part of the capacity of the 
bottle, otherwise they arc apt to boil over when the action comes 
to be powerful, and the disengagement of gas rapid. When the 
materials constat of a liquid and a fine powder, the liquid should 
be put into the vessel first, and the powder afterwards, and the two 
should be carefiilly mixed by shaking the vessel. You must take 
care not fo respire an atmosphere contaminated by ddeterioua 
gases. Sulphuretted hydrogen gas is a particularly powerful poi- 
son, and itisfortunate tliatita noisome odour gives timely notice 
of its presence. Chlorine gas is exceedingly difficult to breathe, 
but it IS not so injurious as the preceding. Arseniuretted hydrogen 
gas is very dea<(ly; a celebrated German chemist was killed by 
smeUing it. Carbonic acid gas occasions sufibcation if mix^ 
with the air in large proportions. Experiments with deleterious 



MAMAGBJinNT Of QABBS. , '20S 

gasee oaght not to be made in a close apartment, but either un- 
der a large cliiinney or in the open oir. The first portion of 
gas, rf whatever kmd it msy iJe, evolved &om the vessel in 
which it ia formed, u always contaminated with the conunon 
air with which the ysmel wag filled at the beginnmg of the ope- 
ratiim. Aqnantitvof the firsts^ received, equal in bulk to twice 
the capacity of Uie veagel, must, therefore, in order to avoid 
accidents and iailiu^ be thrown away. The meaguring of tiiis 
quMitity is effected by collecting it in glaae jais over water, by a 
method to be described immediately. 

It is sometimes necessuy, ddrlng a distillation, 
to give a freah supply of acid to the mistuiji in the 
gM bottle. To be enabled to do this without in- 
terrupting the pntceae, it is proper to provide the 
neck of the bottle with a cork containing two 
: boles instead of one. You fix into ons of these 
mdinto 

upper end, and with a neck a, bo long that it 
dips into the liquid contained in the gas bottle. 
It is by means o£ this fonnel and tube, that you 
are to mtxoduce the acid at all times when it isre- 

When tke gas bottle is to be ezpoeed to heat, it 
must he held over the lamp by one of the snpp(»tst or retort 
stands, already deecribed. 

Clabe's Gib Bottir. — Thfl following apparatus is extremely 
useful in preparing sulphuretted hydrogen gas, to be used in 
testing, or in preparing hydro- 
gen gas, carbonic odd ^;bs, or 
any of tlu>8e gases which do 
not require the application of 
heat to the matemla which 
yield them. I shall describe 
this bottle and the method of 
preparing aulphuretted hydro- 
gen gaa with it, as an exam- 
ple ofitsuse. a is a glass bottle 
six inches high and two inches 
r wide ; c a coik adjusted to the 
nedi of it; 6 a round piece of 
wood cemented to the cork ; d 
a glaas fimnel with a long and 
narrow neck, passing through 
and cemented to the wood and 
cork ; e is a bent tube nearly 
half an inch wide, termmat- 
in a spreading mouth adapted to receive a cork ; / is a nar- 
ir glass tube open at both ends and fixed into a cork that suits 




210 HANAQBMXNT OF GASBS. 

the opening of the vide tube. All the parts of the apparaloa, 
therefore, hang together by the wooden block 6. 

Lumps of sulphuret of iron are put into the bottle a, and 
water is added till it lisea about an inch and a half in the bottle. 
The cork c vitb its appartenances, is then fixed in its place ; 
Hulphuric acid is pouted little by little down the ftmnel d ; upon 
which sulphuretted hydrogen gas is soon produced and expelled 
firom the mouth of the tube f. Ah the general puipose of pre- 
paring this Kas is to pass it into a liquid to ascertain what coloured 
precipitate it gives, the size and height of the bottle is adapted 
to this object. Tiie liquid to be acted upon is put into a test 
kIsss aa represented in the figure, and as described at page 53. 
The tube / is made of such a length aa to pass nearly to the 
bottom of the test glass. The liquid in the hottle a rises in the 
tubcfJBS high as is equal to the dip of the tube/into the liquid 
in the glass g. But no inconvenience arises &om this, and if the 
proportions of the parts of this apparatus are properly observed, 
there is never any violent effervescence, or absorption, or other 
accident produced, to intenupt the experiment in progress. 
. When the operation is over, and no more gas is required for a 
time, the cork c is removed from the bottle a ; the liquid is 
thrown out, but not the solid sulphuret of iron ; the latter is • 
rinced with clean water which is thrown away, and then the 
battle is filled up with clean water, the cork is put in its place, 
and the apparatus is set aside till the kks is Bgaio in request. 

When the gas produced in such a bottle is to be collected as 
gas, in cylinders, then the tube / is withdrawn and is replaced 
by the tube A, by means of which, properly bent, the gas can 
be conveyed in any required direction. 

- In passing the tube A into a water trough, heed mast be taken 
as to the depth of the dip into the water ;for,as I have said, ac- 
cording to the dip of thu pipe below the surface of any liquor, 
is the height to which the water in the bottle a rises in the fun- 
nel d. If you incautiously force the tube h very &r below the 
surface of the water in a trough, the consequence may be the 
expulsion of the whole of the liquor irom the bottle o, through 
the funnel A. In all cases where it is neceesary to pass the tube 
h &r into a mass of Uquid, the funnel tube d must be lengthened 
as shown in the upper figure on page 209. The notice here given 
applies to all bottles in which th^ is, as in this bottle, a com- 
bmation of two open tubes. 

The next figure exhibits an imitation of the above appa- 
ratus made in stoneware. It consists of a Woulfc's bottle with 
two necks fixed on diagonally. The funnel is here replaced 
by a tube of stoneware, U»e lower end of which nearly touches 
the bottom of the bottle. The other neck of the bottle is about 
an inch wide, and is fitted with a large perforated cork. The 
materials for producing a gas are introduced by this neck, the 
cork being removed for that purpose, and the vessel is emptied 
at this nei±. When the gas issues through the hole in the cork. 




o 



^t 



it is conveyed thence in any direction it may be wanted, by a 
amall delivering tabe adjusted by a small cotk to the large 
•^ ■ — cork. Ah represented m 

the cut, it 13 delivering 

Cinto a water trough ; 
. with a tube of a dif- 
ferent shape it can be 
used in testing with bdI- 
pliurett«d hydrogen gas, 

Clark's gas bottle. The 

opacity of the • bottle 
renders it less conve- 
nient than the glass bottle, but it is much cheaper. The price 
of Jh Clarft's gas bottle is Ss. The price of this stone bottle 
is Is. 6d. or when not fitted with tubes. 
Is. The annexed figure exhibits another 
cheap stoneware bottle adapted for the 
same purposes as the above. It appears 
needless to give any particular description 
, of it, as it B used precisely like Clark's 
I bottle. Both the funnel and the dehvering' 
\ tnbe of this apparatus are of stoneware. 
I The funnel is passed through a cork. — I 
, have several other forms of stoneware flasks 
in course of manufacture, that is to say, I 
have flasks of different sizes and shapes, 

Krt with flat and part with thin round 
ttoms, — some of them making, and some 
under tnal, with a view to ascertain whether 
generaUy useful forma of vessel ibr gas dis- 
tillationB superior to ihoee of glass now in use, and much 
cheaper, cannot be made of stoneware. These trials are how- 
ever not so far advanced as to enable me to give any exact de- 
scriptions of them at this moment ; but I hope and expect to 
suoce^ in preparing cheap stone flasks adapted for use in many 
casea of gaseous distillation. 

CoLLBCTiNO OF Oases. — When glass jars, or any other vessels, 

Xa only at one end, are plunged under water, and inverted 
r they arc filled, they will remain full, notwithstanding their 
being raised out of the water, provided their mouths bo kept 
immersed ; for, in this case, the water in the jar is sustained by 
the pressure of the atmosphere, in the same manner as mercury 
in a barometer. It may without difficulty be imagined, that if 
oommon air, or any other fluid resembling common air in light- 
ness and elasticity, be suflered to enter these vessels, it will rise 
to the upper part, and the water will subside. If a bottle, or 
cup, or any other vessel, in that state which is usually c^led 
empty, though in reality full— of air, be plunged into the water 



212 MANAOIUXNT OF QABBB. 

with ita month downwsnU, scarcely any water vill enter, becaiue 
its entrsnce is opposed by the elasticity of the included air ; bat 
i£, while the reetel is inuaersed, its mouth be turned upwards, 
the ur will rise in bubbles to the surface of the water, leaving 
the water to occupy its place in the vessel. Suppose this opera- 
tion to be performed uader one of the jars which are filled with 
water, the air will ascend as befbre ; but, instead of eacapiag, it 
will be detuned in the npper part of the jar. In this manner, 
therefore, we see, that air may bo emptied out of one vessel Into 
another by an inverted pouring. Just in this manner are gases 
collected in vessels placed in what is termed a pneumatic trough ; 
the ja« which are to receive cert^ elastic fluids, are filled witA 
water, and placed, mouth downward, upon a shel^ and the necks 
of Ntarts, and ends of tubes, from which gases are evolved, on 
directed below holes made in the shelf under the jars ; then the 
gases, as they issue forth, rise in bubbles through the water, 
enter the jars, driving thence the water, and occupying its place. 
When, therefore, the jars are thus ranptied of water, they are 
filled with gas. 

The pneumatic trough is simply a wooden 
tnb, OF vessel of tin-plate, filled to within two 
inches of its top with water It should be pro- 
vided with a snel^ placed an inch below iht 
surface of the water, or with a wooden block, 
cut into the form shown by the figure, and 
plugged with lead t^i make it sink in water. 
When you wish to fill a jar with gas, you 
place it full of water, in an inverted position, 
over the hole cat in the block, tuad you direct the point of the 
tube whence the gas is to isnie into tnis same hole. The water 
in the tub must rise about an inch 
above the top of the block. The 
size or form of the trough is quite 
immaterial. A wash-hand basin 
aniweiB the purpose very well. 
The annexed figure exhibits tiie 
mode of putting t^^etbei a pnen- 
inatic apparatus, such as has been 
here described. 

1 shall describe a difFeient sort of shelf and pneumatic tnragh 
presently. 

RscKtvsRS FOR Gases. — Any kind of glass vessel can be em- 
ployed as a reeeiver Sot gases ; in the last figure, a plain cylin- 
der is repreeestod ; but particular experiments require vessels of 
a particular size and form. This will be adverted to when ne- 
cesauy. Lecturers on chemistry generaUy employ a metallic 
MS holder to contain large quantities of oxygen or hydrwen gas. 
If at uiy time a laive quantity of oxygen gas is prepared, when 
no gas holder is at hand, it may be put into green glass wine 





HAMAOBMBNT OP OASEG. 213 

bottles, and corked tip. Each bottle shonld be placed aside, 
bottom upwards, with the mouth plunged into a little pot of 
water. The gas will not escape. 

AWlien a battle has been filled with gas in the 
manner described above, it may be corked under 
water, and then removed from the trough. If a 
jar with a wide mouth has been filled, you must 
fill a tea saucer, a soup plate, or other shallow vea- 
8el, with water, and shde the filled jar from the 
block into the sonp plate, the small quantity of 
(i^^^ water contained in which will prevent the escape 

^- ' of the gas from the jar. 

Little trays of stone ware are prepared for this purpose in 
Glasgow, Three sizes are to be had. The price of each of which 
is three halfpence, or the set for 4Jd. 

A set of four small cylindrical glass jars adapted for expcri- 
ments upon gases have been described at page 61). The price of 
the set is 2s. Another jar useful in eucfl. experiments as the 
burning of phosphoms m oxygen gas, open at the bottom and 
with a wide neck at the ton, should also be provided. The 
price of such a jar of five inches in height is Is. 

Wlien yon want to transfer gas from a wide mouthed into 
a narrow mouthed vessel, you must hold a funnel in the mouth 
of the latter. All transfers of gas must be effected under water, 
and, aa it has been expressed above, by an inverted pouring. 
As wafer emptied in air descends, so air emptied in water as- 
cends. This is the principle upon which depends the decan- 
tation of gases. 

Filling of Bladders with Qaeea. — As it ia freiiuently necessary 

to fill biaddcra with gases, 1 shall describe the method of doing 

it. The following fig^ure represents an apparatus employed for 

this purpose, a is a glass 



^ . is open at the 
bottom, and provided with 
a brass cap and stop-coek 
at the top. A vessel six 
inches in diameter and 
eight inches high, is suffi- 
ciently largeibr a student's 
experiments, rf is a blad- 
der, in the mouth of which 
a atop-cotk is fastened by 
means of a ferrule, f is 
the side of a pneumatic 
trough ; A is the shelf, g 
the level of the water, e 
andftare thest«p-cocksby 
which the bladder and re- 
ceiver are connected. 



S14 MAKAGBUBNT OF flABKB, 

Moisten the bladder with water to render it flexible, squeeze 
it oloae to expel the common air trom it, then shut the atop 
cock e, and screw it to the stop-cock 6, on the top of the re- 
ceiver, which is supposed to be placed on the shelf in the trough. 
Next, open both the stop-cocks, hold the apparatus in the man- 
ner shown bv the figure, gently slide the receiver off the shel^ 
and press it down into the water; the gas will soon enter and 
fill the bladder, being forced through the opening by the up- 
ward preasure of the water. The stop-cocks are then to be 
dosed, the receiver replaced on the shel^ and the two vessels 
disunited. Previously to undertaking experiments on gases, the 
young student should accustom himself to the dexterous m 
" "anent of gases, by performi" ~ *'" " ' ' ''' 

iug of bladders, &c, with ci 

Stoheware Oas Holder. 

In all cases where a aerieg of esperiments with the same ^ 

are to be performed, as when a teacher has to demonstrate the 

Kaperties of oxygen gas or hydrogen gas, it is eonveuient to 
gin by preparing a quwitityof gas sufficient for the perform- 
ance of tne whole series, and then to proceed unintermptedly 
with the experiments. I shall here describe a cheap and handy 
apparatus for storing gas for this purpose. 



a is a stoneware bottle of about a gallon and a half capacity, 
or about 10 inches in diameter and 13 inches in height. It ia 
tiunished with three necks, b, c, d. The neck d ia fitted with a 



HANAOKHSNT 07 OASES. 215 

cork. The neck b is provided with e, stop-cock, /, which is 
cemented into it. The neck ciscemraited round the upper Mid 
of a metal tube, whicji descends veiy nearly to tlie bottom oi 
the bottle. There ia a coupling screw soldered to the t^ of this 
tube, to which the large japanned iron funnel e can be con- 
nected when neceesary. g h a flexible metallic pipe two feot 
in length, connected to/by a screw. 

To fill Mu Gag Holder vnth Water. — CloM the neck d with ita 
cork. Opat the atop-cock /, and pour wato' into the fiumel e, 
till it runs out at/, (the tube g beuig supplied away). 

TofilllheGa»SoldertDilhGa».~Ciose the atop-cockf. Take 
ont the cork at d, and pass into the neck d, the delivering tube 
which comes from the battle in which tbe gaa ia being [separeil. 
Tlie gaa will then riae in the vessel a, and an equivalent bulk of 
water will flow out at d. Of course, the gas holder roust be 
placed during tliis process over a tub sufficiently large to re- 
cdve the water that runs out. The quantity of the water thus 
collected, shows the quantity of gas that has entered the gw 
holder. When water ceases to run out of the mouth d, not- 
withstondinK the continuance of the deliv^^ of the gas into it, 
the gas hol&r ia filled with gas. 

Stonb Pneumatic Tbotwh. — Before noticing the method of 
expelling the gaa from this gas holder, it is pnqjer to describe a 
new form of pneumatic trough which is to be used with it. 

h, in the last figure, is this trough. It is a pan of stoneware 
11 inches in diameter, and 5 inches deep. The shelf for support' 
ing the jara in tliis trough, and for gathcriog the gas beneath the 
jars, ia the moat peculiar part of it^ Tiiia ia represented by let- 
ter i in the above figure, and under difierent points of view by 
the two figores below. 



This shelf is an inverted stone pan, cylindrical on the outaid^ 
but shaped like a bee hive within. It is 4 inches broad, and 3J 
inches high. On the side it has a round opening of 2 inches dia- 
meter to admit the entrance of retort necks and d»livering tubes, 
and in the top it has an opening- of half an inch in diameter, to 
permit the passage of gas from the bec-hivc below, into the jars 
placed upon it. When this shelf is put into the trough, hut 
dose to one side of it, there ia room left for working with pretty 
large cylinders. The gaa ia collected veiy effectually from any 



216 MANAGKHBNT or OUnt. 

sort of deliTovig ]^pe, and with great Teadineas, and vithont any 
toss, it ia conveyed eriin into narrow mouthed flasks, placed in 
thepoution indicated by figure k in the cut on page 214. 

To pMt Oat from the Oat Bolder into a Jar. — The flexible 
metal pipe is first placed in the position shown by the figure on 

n^ 214, and adjusted to tlie bee-hive and trough, which is 
ed with water to within half an inch of the top. The jar is 
filled with water, inverted, and placed upon the beo-hive in the 
trough. The funnel e is filled with water. You have then only 
to open the atop cock J, when the gas immediately passea into 
the jar k. When the jar is as full as you wish it to he, you close 
the stop cock/. 

In experimenting with this apparatus it ia advisable slwa^to 
use cylinders of a smaller capacity than the Jiinnel e, in order 
that one filling of the ftmnel may be sufficient tor each experi- 
ment. 

TofiU a Bladder or a BaUoon tri(A Qat/tvm the Oct Bolder.— 
Attach the compressed bladder to the end of the pipe g, pour 
water into the funnel e, and open the atop cock./. 

In the same manner can the gas be ibrced out upon-any given 
object. Thus, oxygen gas can be forced out upon burning 
charcoal to cause the fusion and combustion of met^ &c 
Hie price of this gas apparatus is as follows : — 

Ou holder iiitfa funnel uid Sexibis pipe, . Si. Od. 

IhieuniBtlc trough uid bee-hive shelf, . . Ss. Od. 

Setof4cj1iDdricdglusjBr9, . . . Zs. Od. 

Open glus jir fOr defluntion, . . . . Ia. Od. 
Iron «poan for deBigntlon, . . Os. 6d. 

Set or 3 itone tr>ys for the Jul, . . Oa. 4M. 

14i.'4id.' 
It Is scarcely necessa^ to add that this is the cheapest gas 
apparatus that haa eyer been produced. 

Jafuined Wateb. Tiiairou. — Thefigureon p. 217, rejtresents a 
Tery light and convenient pneumatic trough made of japanned 
linplate. It is adapted for experimenting with jais of 60 cu- 
bital inches and under. The trough is 10 inches long, 6^ 
inches wide, and 4 inches deep. The dear water way a mea- 
sures 10 inches by 4 inches. The shelf 6 ia J inch wide. The 
shelf c is li inch wide. These shelves arc made by bending 
a tin plate into the form shown by the end of the trough e. 
At the owner of the trough / there is a small tube wliich 
carries off the water that descends from jars when filling with 
gas, as soon as the level of the water in the trough arrives 
within half an inch of the edge. A Beparato tray, of the uze 
of the cavity a, is provided to catch this water, and is placed 
fcr that purprac lufler the side /of the trough. The ^elf d is 
moveable and slides between the shelves b and c, the whole 
length of the trough. A small box is made below the shelf d, 
to catch the gas from the delivering pipe, which is brought 



MANAGEMENT OF GASES. 217 

below it, and a email hole in the upper 
part of the box permits the gaa to paas 

into jars placed above it. In operating 
with this trough, yon place it crOBswise 
on the table before you, with the end e 
to your right hand. The bottle in 
which you are preparing the gaa that is 
to be collected, must be placed upon 
your left hand, with the deUveriug tube 
dipping into the water trough just low 
enough to go under the box soldered 
below the shelf d. You then fill the 
a jar with water, invert it, and 
r place it upon the shelf d, and adjust 
I the latter over the mouth of the de- 
livering tube. When the iap is full, 
you remove it upon a small tray, and 
place it, if you wish to set the small 
tray at liberty, in the long fray which 
serves to catch the overflowing water 
from the trough. By this means the long tray is rendered 
equivalent to extra shelf room in the trough. The price of this 
trough, 3 pieces, japanned, is 4b. 

Mbrcubt Troi-or. 
Many kinds of gas are condensed by water, and cannot he 
collected in jars inverted over water in the manner described 
above. Such gases can only he confined by mercury, for which 
reason it is necessary for the chemist who desires to operate 
upon gases of that kind, to be provided with a trough contain- 
ing a quantity of mercury. The expensiveneas of that metal 
makes it de»rable to have the trough so formed as to take as 
little mercury to fill it as is consistent with the power of per- 
fbrming the necessary operations. I shall describe two troughs 
of this description. 
Berlin Porcelain Trough for Mercury. — The iigures represent 
a surface view and a section of 
this apparatus. It is 7 inches 
long, 4 inches wide, and 3 in- 
ches deep, o a are two shelves 
IJ inchhigh. Thepriceofit 
in Glasgow is 10s. This trough 
is employed by Liebio as a part 
of his apparatus for Omnic 
Analysis, and it is used by 
several of the German chemists 
in the performance of class ex- 
periments. It requires about 
101b. of mercury to fill it pro- 
perly. 




,,glc 



MAN^avMBNT or OAns. 



Stoneaan Mercary Trough. — I hare Ittteljr made some en- 
deftvoim to coutmct a stoaeware trough, tliat should be lower 



in price than the foregoing, that ghonld require a Bmaller 
quantity of mercury to fill it, and yet be luge enough to 
peTmit of the perfomiance of Tery satisfsctory enerimenta. 
The result is depicted in the abore cut. It requires 41bB. of mer- 
cury to fill it. It takes in a tube 6 inches long and 1 inch wide, 
aud allows it to be safely inverted when full. At a there is a 
shslf upon which the tube rests to be filled with gas, which can 
be passed in by a delivering pipe under the bee-hive o, whence 
it passes through a hole at e. At o, i, there is a cavity which 
admits a glass tube 2 inches by i inch, and gives the operator 
the power of patung caustic potash or other re-agent into the 
cylinder placed al>ove the hole *. Between a and t are two ra~ 
ceeses wtuch afford pasB^c tor a. thumb and fingo", to man^e 
the small tube depregsed for this pui^KMe into the cavity o i. 
The following figure gives a surface view of this trough, which 



bears some resemblance to an Egyptian mummy case, while 
the aide view of the apparatus is not very unlike a shoe. The 
price of it is Is. 6d. When in use, it rei^uires to he placed in a 
dish or tiay to catch the mercuiy which may run over the 
edge during the operations. The stone water trough, page 214, 
answers this purpose vety well. 

Cooper's Mercuiual Reobiver. 
The following cut exhibitB a method of collecting eas over 
mercury in a tube, and therefore t£ diepenung with the use of 
B tronglt. ef,e/, are two tube holders, such as are described 
at page 41. a is a flask in which a gas is supposed to be eene- 
ratme; b a narrow tube for delivering; the sas; c a corK b^ 
which the delivering tube is adapted to the flask, d d is 
Cooper's bent gas receiver. The length of it is 12 inches to the 
elbow ; the neck is 2 inches; the width, i inch. It is closed at 
the top, but open at the bottom. Atthe beginning of the oper- 
ation, this receiver is filled with mercury, and a basin is placed 
below the mouth of it to catch the mercury which may be 
displaced by the gas. The operation is stopped when the tube 
is filled with gas nearly to the nend. The fiJlowing account of 



UANAQXHINT 




the method of exammlng & gas collected in ancli a tube receiver, 
1 take the liberty of extracting from Dr Paiudit'b " Chemical 
Manipa lation." 

" The gas thus collected may be examined as to a ereat nnniber 
of itfi characters without the help of any other tube, or of any 
transference but what may be obtained by moving it from one 
part of the tube to another. For instance, the finger may be 
placed on the aperture, in contact with the metal, so as to ex- 
clude all air, and close the month of the tube ; then inclining the 
tube, a bubble of the gas may be made to pass round the bend 
towuds the finger ; thiB done, upon restoring the tube towards 
an upright position, the larger portion of gas will still be in the 
upright part, but a quantity varying from a quarter to three- 
quarters of an inch in extent, according to the will of the opera- 
tor, may be confined tietween the mercury and the fin^, and 
Suite unconnected with the larger portion. This quantity may 
e tried as to inflammability by bringing a lighted taper near the 
aperture, and immersing it in the gas the moment the finger is 
removed. Suppose this trial made and that knowledge acquired, 
then by pouring in mercury, bo as to fill the small apace now 
unoccupied, ra-applying the finger and re-inclining the tube, 
another portion of the gas is brought into a situation similar to 
the former; this may be examined as to smoU, and its odorous or 
inodorous nature ascertuned. Ag^n filling the ^ace with mer- 
cury, and repeating the operations as before, a third portion of 
SB is brought to the mouth of the tube, and this may be exam- 
ed as to whether it is heavier or lighter than the atmosphere, 
if from tile two previous trials it appeared to differ in quality 



from cmnmon air ; thus, i£, after leBving the mouth open a ihort 
tkae, the gaa, or a part of it Btill remains ia the tube, it moHt be 
heavier ttun air, wnereas if all signa of it have disappeared, it is 
a proof of its lightness as compued with that standard. In a 
aimilBT manner trial may be made of the solubility of the gas in 
water, by filling up the space left by the last exp^iment with 
water instead of mercury, or at least in part by water, and then 
bringing a bubble of gas to that part as before ; if it instantly dis- 
appear, it indicates considerable solubility, if it does not at all 
dmiinish, it shows comparative ingolubility. If a solution be ac- 
tually formed, then upon removing the finger it may be exam- 
ined as to its acid or alkaline nature, or other properties. 

" In these and mmilar experiments great care should be taken 
that no water pass beyond the bend into the tnbe, for which 
reason but little water should be put in at once ; there should be 
Builicient mercury between it and the angle to replace the bub- 
ble of gas which is to be brought to the mouth, and the inclina- 
tion of the tube shonld be carefully attended to, that no water . 
inadvertently pass backward into the higher part. When the 
trial of solubility is over, the water should be taken irom the 
mouth of the tube, first by a folded piece of bibulous paper, and 
afterwards with tow upon a wire- Trials may he made with 
liroe water or alkaline solutions, their action upon a part or the 
whole of the gas bring in this way easily obeerred. 

"Thus the gas may be divided into many succesaive portions, 
and submitted to nnmerous examinations; and should it so hap- 
pen that a part is absorbed by water and a gas left which could 
not be properly examined wlulst in a state of mixture, then, after 
having made the proper experiments upon the mixture, a little 
water may be let into the liody of the receiver, and shaken with 
it, to absorb the soluble gas, and the finger being removed Irom 
the aperture, either under mercury or water, those fluids will 
enter and supply the place of the absorbed substance. The in- 
soluble and purified remainder may now be examined In succes- 
«ve portions in the manner just described." 

Tube 



The following appaiatns pretty nearly resembles Coopers Ti 
I its nature. It is useful in cases where the relation of a 




I , Google 



UANAfllUIEKT OF 0A8BS. 221 



to a partionlar liquid is to undergo examination. For this pur- 
pose, the tube is three parts filled with the liquid in question, 
BO as to shut out atmospheric air from the branch d. It is 
then fixed in a slit boafd or in a tube holder, in the position 
here exhibited, and the gas delivering tube, a c, is then inserted, 
and the gaa passed up into the liquid between c and b. Its ab- 
sorbability is thus readily ascertained, and the resulting solu- 
tion can be readily examined. If any gas remains nnabsorbed, 
and is to be further examined, the tube must be first filled with 
water, and the fine point d be then plunged into water, and 
broken off below a vessel placed to receive the liberated gas; or, 
after closing the tube bytiie thumb, the gas may be transferred 
to the branch a c, and be let out at the mouth c. 

This apparatus can also be usefullv emploved as a receiver in 
the distillation of nitrous acid and other condensable gases. The . 
retort, containing the materials for producing the gas, is ad- 
justed by means of a perforated cork or a caontchone connecftr 
to the month a of the recover, which is to be supported by a 
tube holder, A bulb retort, such as is represented on pa^ 200, 
answers this purpose best. The bend of the receiver is then 
to be dipped into a mixture of ice end water, or to be loosely 
wrapped about with tow, and kept constantly moistened witn 
ice c^d water. Heat being applied to the retort, nitrous acjd 
passes into the receiver and is condensed at the bend e. 

Glass Pneuhatio Troitoh. 

The trough exhibited in the following cut is ad^^d for the 

Lecture Table. It is constructed of plate glass, bound tojjether 

by a frame of polished brass. The operation exhibited m the 




cut is the preparation of spontaneously combustible phosphnr- 
etted hydrogen gas. The dutiUation is effected in a retort, which 
is supported upon a shallow sand bath; a method of spreading the 
beat of a lamp which is useful in ma^ cases, and frequently 
eaves a glaas vessel from destruction. The neck of the retort is 
gripped by a Gay Lussae's retort holder (page 3S.) 

Here is another representation of the glass pneumatic trough, 
vrlththe addition of its pl»te glass shelf for the support of jan, 



UANAaEMBNT OP OURS. 



the shelf itself bein^ sapported by a frame of brass which fits 
the edges of the tiongh. The operation exliibited in this print 
is the preparation of chlorine gas. 1 recommend your observ- 
ance of the method of adiuatine the parts of the apparatus, 
and the mode of seciiriDg the fla£ above the lamp. 








Gihh'b Cvlindsr Hou)bb, 
The folloving is Benelins's account of Gahn'a holder for 
flasks, cylinders, and bell jars, 
■*■ over the pneumatic trough. 

The first <H the following fig- 
\ tires. A, represents the prin- 
cipal portion of this apparatus, 
as when teen &om above. 
The second figure, b, exhibits 
the same in profile. The in- 
strament is made of wood. A aUt three qnarters of an inch 
deep is sawed in the block at a b, and in this slit a strong silten 
band or ribbon of the some 
width is placed, the end of 
it being secured ty a thick 
edge or seam down the side 
h. The end of thia hand is 
then carried round from a, 
in the direction x h s i &, 
taxi throngh the slit / g, 
(fig. B.) into the conical 
hole 0, where it Is fastened 
in another slit, k i, eat in 
the conical peg ». The 
bond is woimd np round 
this conical peg and fixed. 




HANAaBHENT OF 0ASB8. 223 

when neceasaiy, by presaing the peg into the conical hole. Con- 
renely, the band con he loosened by slackenrng the conical pe^. 
Conseqaently, e. glass cylinder, as o, placed 
in the triangular opening A i, can be held 
fast or let loose at pleaaure. The remun- 
ing part of this apparatus consistB of the 
frame, i s u, which can be Bciewed to the 
Bide of a pneumatic trough by the screw at 
M. The upright rod, h d, is cylindrical, 
the arm i ia Bquafe, and adapted to the 
gqnare bole f shown in figure a. The two 
screws, h and s, permit of all requirit« ad- 
justments ofpositioD, and when the inatni- 
ment is mfiQctently strong, it holds the 
glass jar with perfect steadiness. The oper- 
ator who has once experienced the great 
convenience afforded by this instmment in 
experimenting upon gases, says Berzelius, 
will be extremely unwilling to dispense 

The price in Glasgow of this apparatus, of 
German make, is 8s, I shall describe a 
J cheap modification of it, under the head ol 
" Universal Support." 




COLLECTINO OF QaSES BY DiBFLACBHGNt. 

Several gases, which are either lighter or heavier than at- 
mospheric air, may be collected in tolerable purity, and with- 
out the aid of any trough, as follows ;— 

^^sz3 b To GoUeet Heavy Oa»ea. — Let a represent a cleui 
dry glass cylinder, and i the tube which brings the 
gas to be collected frem the vessel in which it is pro- 
duced. As the heavy gas issues from the tube, it 
settles at the bottom of the cylinder, and forces the 
lighter atmospheric air to ascend and flow out of the 
top of the vessel. Thus the heavy gas gradually 
displaces the ur, and soon fills the cylinder. ChlorineL 
muriatic acid, sulphureous acid, and carbonic acid 
gases can all be collected in this manner. You 
readily ascertain when the vessel is full of chlorine gas, in con- 
sequence of the yellow colour of that gas. Muriatic acid gas 
flows over and produces &mes in the air. You test the fulness 
of vessels containii)g carbonic acid and snlphnreous acid gaa, by 
putting a lighted match near the opening. If the light goea 
out, the gases have risen to the top. .You must allow a little 
KM to flow over, to ensure the expuMon of all the common air 
from the cylinder. It is best to use a very small receiver, and 
to conduct the operation slowly, and when the receivw is &11, 
to remove it from the delivering tnbe gradually. 



224 



HANAaXHXKT Ot OASKS. 



To OoBeet lAght Oattt. — Oases that are lighter than 
atmtH^heric air, snch, for example, tta aminoiua, can 
be collected by a process which is the reverae of the 
preceding, and which is pictured in the margin. A 
tube pBMes upfnardg to the top of a receiver, the light 
gas escapea from the tnbe, settles at the top of the re- 
ceiTcr, and depresses and drives away the whole of 
the atmosphenc air. By holding a slip of wet tur- 
meric paper to the moath of the jar, you easily leam 
when it IS fnll of ammoma, because turmeric is co- 
loured red by ammonia. 

When gases are thus collected, they can be se- 
cured in Dottles by the insertion of greased glass 
stoppen, or in cylinders by the application of greased glass 
plat«s. But gases thus collected ought to be immediately sub- 
mitted to experiment. 

Dkyikq or Oabes. 
It is often necessary to prepare a current of chlorine gas or 
hydrogen gas, freed mm wat«ry vapour. This is the appara- 
tos employed ftit the purpose : — 




The gas is prepared in the flask a, whence it passes into tlie 
two necked receiver, or intermediate vessel b. A good deal of 
the moisture is deposited there, whence the gas, pursuing its 
course, passes into the tube c, which is filled with lOmps of 
chloride of calcium, recently fused to deprive it of water. This 
, substance eagerij abstracts the vaponr from the gas, and the 
latter issiies nirth at the other end of the tube perfectly dry. 

The tnbe c employed to contain the chloride of caicinm, best 
answers the purpose when it is about 10 inches long and two- 
thirds of an inch wide, and is closed at each end by a cork with 
a short piece of gas delivering tube passed through it, as repre- 
sented m the figure. 



UANAOElfENT O 



The ends of this diying tube are not fixed immoveable to the 
other parts of the apparatus, but are connected to it by means 
of abort tubes of indian mbber of the following size, and tied on 
in the following manner : — 



mm 



I 



1 shall describe the method of making these tubes in another 
section, making here only the remark that they are extremely 
useful in connecting together the tubes of a distilling apparatus, 
because they easily m&e air tight junctions, while they permit 
a considerable degree of moveability among the connect^ Te»- 

Meaeukeueht or Oises. 
Gases ate measured by being introduced, either over water or 
mercury, into jars or tubes graduated into parts of equal capa- 
city. The accurate measurement of gases cannot be effected 
without taking a variety of precautions. 

Weighing of Oases, 
To ascertain the specific gravity of gases, it is necessary to 
have good apparatus and great skiU in experimenting. A ^aas 
globe, provideil with a stop cock, is weighed. It is then ex- 
hausted of air by an wr pump, and weighed empty. It is after- 
wards filled with gas, and again weighed. The weight of the 
comtnoD, air, compared with the weight of the gas, shows, the- 
specific gravity of the latter. 

If it were any part of my object, in tbia work, to treat with 
precision of quantitative analysis, the subjects of the last two 
paragraphs would have been discussed at considerable length. 
As it is, 1 pass them over with these brief notices, referring those 
who require more ample information on these points, to Dr 
Faraday's work on Chemical Manipulatum, 

Metailio Reductions effected bt Gases. 

Hydrogen gas, chlorine gas, and some others, are irequently 
passed over substancea heated in tubes, for the purpose of effect- 
ing particular decompositions or reductions. 1 shall, as an ex- 
ample of thia method of experimenting, deBcribe,'after MiTCCKsa- 
LiCR, the reduction of mel&lllc oxides Dy means of hvdrogen gas. 

The oxides which become decomposed when heated with 
hydrogen gas, are pretty numerous, embracing those of cobalt, 
iron, and copper. Their oxygen combines with the hydrogen 
and forms water while the metals assume the reguline state. 

I ;; Cookie 



MANAOBUBNT or OASBB. 




The hydrogen gas is sIowIt generated in the flask a. To ae- 
pamte the aqueous rapoiir m>m it, two bulbs, e e, are blown 
upon the delivering tube. The water which does not condense 
there is fully absorbed by the fused chloride of calcium, with 
which' the drying tuhe.d is filled. The gas then passes in a diy 
state into the bulb e. In this bulb is placed the metallic oidde 
which is to be reduced, oxide of copper, for example. When 
the apparatus is Med with hydrogen gas, a spirit lamp ia appliod 
below the bulb e. Only a slight neat is necessaty, for when the 
action of the hydrogen be^ns to take place, so much heat is 
produced by the conreTsion of the oxygen and hydrogen into 
water, that the solid metallic oxide becomes red hot. The water 
produced passes into the bulb g, and is there depo- 



sited in the liquid state ; but to prevent the possible escape of 
any water with the superfluous current of hydrogen gas which 
continually Ibsugh from the tubes, a second drying tube k u 



added to the apparatus. The excess of hydrogen gas, in a per- 
fectlv diy slate, then escapes at the pomt i. The bulb e is 
weiaaed previous to the operation, both emptj- and when filled 
witE the oxide of copper. The bulb g, and the drying tube A, 
are also weighed previous to the operation. When all is ended, 
the bulb t is weighed again with the metallic copper within it. 
The lose of weight shows the quantity of oxygen which has 
been abstracted. The bulb g, and the tube A, are also weighed 
again. Their increase of weight consists of water. The'd^er- 
ence betwixt the weight of the water produced, and the weight 
of the oxygen lost, shows the weight of the bydrc^n which is 
required to produce a eiven quantity of water, by combining 
with a given quantity of o^gen. 

This expennlent serves therefore to show not only the com- 
position or relative component parts of water, but also the com- 
position of the metallic oxide employed in the operation. 

The size of the bulb and tube best adapted for use in experi~ 
ments of this sort, is shown by the following figure. Notning 
hut hard German glass can possibly be employed for such an 



tlANAGBMENT 01' OASIS. 




In some cases decompositions of this sort axe effected at very 
high temperatures. It is then necessary to place the sohd 
matter wtuch is to be reduced in a tuhe of glazed porcelain, and 
to fix the porcelain tube across a furnace. In other cases, it is 
useful to place the subject of experiment in a glazed porcelain 
tray or narrow capsule, such as la represented in the following 
fibres. This gives you the power of weighing it both before 




and after the experiment, vrhich is scarcely possible when the 
substance ib placed in a long tube. The ring at the end of the 
tray is to permit it to be withdrawn from a tube by means of a 
crooked wire. Such trays can also be employed in exposing 

giwders to beat in an iron tube. Two sizes of these trays of 
eriin porcelain are now to be had in Glasgow — 

No. 1, three inches long, .... price 8d. 
S, four inches long, 8d. 

The prices in Glasgow of glazed Berlia porcelain tubes are as 
follow — 

Hkir-Inch wide, 6 inchsslinig, . . . price 8b. 4d. 

, ^ j3 inches long, . 4s. Od. 

: ,»} inches long, . . . . 68.6d, 

I) Inch wide, 15 Inches long, ... 8b. 6d. 

SoLUTlOn OF OuES. 

When gases are prepared for analytical experiments, they are 

geneiallv made to act upon liquids. In this case, the extreme 

end of tne delivering tube is made to dip into the liquid which is 

tobeexposedto the action of the gas. In proportioa aa the gas 



HANAQBUBNT OF OASB8. 



a 



bforcedfrom the flaakinwhichit is generated, it passes into the 

liquid at the end of the tube, and is there absorbed. The liquid 

' "~" '""^ to he acted on by the gas, may be contjun- 

ed either in a test gla», a cylindrical solu- 
tion jar, or a bottle provided with a glass 
Etopper. The latter is often made ose of 
with advantage when the liquid is to be 
completely saturated with the gas. When 
the gas has been passed for some time into 
the Equid, you withdraw the bottle irom 
"^^^ the tuDe, put in the stopper, and shaJfe the 
bottle. If, upon withdrawing the stopper, there is a rush of air 
into the bottle, the liquid is still unsaturated; if, on the contrary, 
there is no ru^ of air, and the bottle smells strongly of the gas, 
then the liquid is near the point of saturation. 

Experiments of this description are liable to a variety of ac- 
cidents, unless they are performed with a suitable degree of care. 
I shall mention these accidents, and the means oi preventing 
them. — 1. If the mixture which disengages the gas is thick, and 
(he effervesenoe so powerful as to force a portion of the mixture 
into the tube, ttie bottle may burst, in consequence of the ina- 
bility of the gas to escape through the obstructed tube. To 
prevent this, you must, as before (Greeted, put but a small quan- 
tity of the mtxture into the bottle, and you must keep the ac- 
tion moderate and regular by a suitable apphcation of heat. — 2. 
If the mixture boils over into the liquid which is exposed to the 
action of the gas, the whole operation is spoiled. To prevent 
this, yon must take notice when the mixture rises up in the 
battle, and eiither remove the lamp from below the iKittlo, or the 
liquid fcom the mouth of the conducting tube, — 3. If the disen- 
gagement of gas from the mixture happens to slacken, in conse- 
quence of the application of too low a degree of heat, or of some 
other cause, a vacuum is produced in tho bottle, and the liquid 
which is exposed to the gas is forced through the gas tube into the 
bottle. In this case, the operation is ruined, thu liquid lost, and 
very often the bottle broken. To prevent this, you must keep 
the tube dipped but a little way into the liquid, so that, when you 
observe the liquid begin to mount into the tube, you have 
Mily to lower the vessel a httle, so as to bring the liquid below 
the mouth of the tube, to avoid the above effect. You must also 
take care to heat the gas bottle with a steady and regular fire. 
Remember, that an operation of this sort must never be neglect- 
ed. Youmust watch the progress ofadifltDlation as a cat watches 
amouse. Yonr eyes must neverbeoffthe vessels, and vour hands 
must never be occupied with any other business than that belong- 
ing to the process. A «ngle moment of inattention may mia 
the result of many days' labour. 
The eagerness with which the solution and the mixture in the 



gas bottle encroach upon each other's domain are such, that it it 
advisable, in all experiments of importance, to place an interme- 



MANAOEMBNT OP 0ASB9. 22'J 

diote Teaeel between the otlier two. This may be a Woolfe's 
bottle, OP a receiver with two necka. The three bottles are con- 
nected together by corka 
and glass tubes. In this 
CB^ the solution is less 
liable to be spoiled, and 
the gas bottle less liable 
to he broken, than whea 
the solution and the bot- 
tle are connected only by 
ft single tube. 

The following appa- 
ratus, employed in the 
preparation of umriatic 
acid, exhibits an exam- 
ple of tlie use of the 
I mtermediate vessel. The 
use of the bent funnel or 
safety tube, I shall des- 

icribe under the head of 
Wonlfe's apparatus. The 
rest of this figure will be 
lined when 1 come to the article "Muriatic Acid." 
preparing a small quantity of a solution, Mr Davy's hulb 
sometimes useful. It affords a pressure which facilitates the 

V saturation of the liquid, but it is a com- 
paratively expensive form of apparatus, 
and is too easily broken to be fit for 
common use. It is shown in the margin. 
The stone bottle described at page 211 



•t 



of many gases. It should be half filled 
with liquid. The wide diagonal tube 
should be pushed into the bottle till it 
just enters the liquid, but it should not 
dipfarinloit. You learn when the point 
of it is below the liquid by blowing down 
it. When the tube has been previously fixed in the bottle, you 

Sour water through the wide mouth until you find, by blowing 
own the tube, that the water covers its lower end. The wide 
mouth of the bottle is then closed, and the gas delivering tube 
is passed down the wide diagonal tube till it projects beyond it, 
whereupon the gas passes clear of the wide tube into the liquid 
and is absorbed. 

Woulfe's Apparatus vob Compound Distillation. 

In several cases of diatitlation, the substance raised is partly a 

condensable fluid and partly a gas, which gas is inconaensable 

by itself, hut capable of being condensed by being transmitted 

through a liquid. The apparatus required by a process in which 



,31c 



230 

this double purpose is effected, is represented by the following 
figure, and is ccoimonl}' termed Woulfe'H apparatus. It is a 
series of reoeivere, connected toeether in a particular manner, 
and more or lesa in number, as the case may require. Tile dis- 
tilling vessel made use of is the retort {pa^ 1 92), into the tubu- 
tnre of which, instead of a glass stopper, is inserted the s^ety 
tnhe, of wbidi a descr^tion is given below. The first receiver, a, 
is joined to the retort, and aas a bent glass tube <, open at 



both ends, fixed into its tubulure. b, the second receiver, is a 
bottle which, besides its usual neck at the top, has an opening 
just where its ades fall in to form the top ; into which opening a 
glass tube is fixed diagonally, and the juncture is secur^oy 
the application of cement. The lower end of this tube must be 
about an inch from the bottom of the receiver, c is in evay^xo- 
i^ct the same as b. The openings spoken of are at g g, «nd the 
tubes fixed in them are shown by d d. The small tube e, which 
rises from the first receiver, passes down the diagond tube in 
the second receiver ; and another small tube, ffliewjoe marked 
ty riung from and cemented into the neck of the second reo^ver, 
passes down the diagonal tube in the third receiver. If there were 
mtffe receivers, they would be like b and a, aod Vonl4 be con- 
nected in the same macuer. The lower entls of the tabes e e 
must project as £ar beyond the ends of the tubes dd,aB they can 
do witiiout toudiing the bottom of the bottles. TTie liquids by 
which the gas is to be absorbed are put into the second, and sub- 
sequent receivers, each being filled two-thirds full, 1'he nature 
of this liquid is regulated by the nature of the gas to be absorb- 
ed, or by that of the solution intended to he produced. For 
gases that are rapidly absorbed by water, such as sulphureous 
acid, &c., distilled water is made use of; for other gases, the car- 
bonic acid, for instance, solution of caustic potash is employed. 
In e^neral, it is advisable to put water into the second receiver, 
and the alcaline solution into the third; the firH receiver, a, is 
always left empty. 

The materials being introduced into the retort, the arrange- 
ments completed, and the joints secured by cement, the distillation 
is begun. The condensable vt^ur collects in a liquid form in 



UANAOBMBNT OF SASBS. 231 

lbs receiver a, which is kept cool by being placed in water, or 
by 'Iiaviiig wet cloths applied to it. In the meantime, the 
evolved gas passes tluxingh the bent tube e, into the water con- 
tained in b, which continues to absorb it, if it ia a gas absorbable 
by water, till it is saturated. When saturation takes place, or 
when no absorption ensues, the gas bubbles up through the 
Water, passes tluough the second pipe e, and enters the receiver 
C. And so the process continues till tbe liquids in all the 
bottlee are saturated ; and then, if any gas continues to be pro- 
duced, it eecwes through the neck / of the last receiver. Should 
it be required to preserve this overplus gas, it may he conducted 
into a receiver placed in the pneumatic trough, by fitting into 
the neck/the bent tube figured at page 208. 

It will be now proper to point out the nae of the 
tube of safety, figured in the margin, and of the 
wide diagonally fixed tubes d d. Supposing the re- 
tort to be closed by a stopper as usual; and suppos- 
ing the bottles to be destitute of those tubes, and 
consequently that e e were luted into the receivers 
at g g, the process would then be liable to be inter- 
rupted by an accident ; for if, in consequence of the 
irregularity of the heat, or other circumstances, a 
vacuum should be produced in the retort, by the re- 
al»orption of gas, the liquids in the dUferent re- 
ceivers, being acted upon by the pressure of the 
atmosphere aXf^ would rush from one int« another 
to supply that vacuum, and by such a mixture of products the 
wbole experiment would be spoiled. I^ on the contrary, gas 
were to be evolved faster than it could be absorbed by the cUf- 
ferent liquids, or than it could escape at /, the apparatus 
might burst, with considerable danger to the operator. Should 
the operator close /as well oli all the other openings, then the 
apparatus would be destroyed, if either absorption or expansion 
took place ; for, in the one case, the external air would press the 
vessels till they broke, and in the other, the same effect would 
be produced by the elasticity of thS gas confined within. Now 
all these inconveniences are obviated by the employment of the 
different tubes. If an absorption takes place, when these tubes 
are fixed in the manner that has been described, the vacuum u ' 
inatantly supplied by the external air, wiiich rushes down the 
tubes d d, into the receivers, and down the tube of safety into 
the retort. The experiment being thus prevented from uiling 
alh^ther, at the price of having a small portion of common air 
mixed with its products. On the other hand, no gas can escape, 
for any pressure within is instantly followed by a formation of 
a bi^ colnmn of liquid in the tubes i^ d, which resists the egrcBs 
of the gas, as long as is consistent with safety. 

The TuU qf Safety is a glass tube about sixteen inches in 

length, and bent as represented in the above figure. One end 

<^ this tube is fastened into a cock, and the other made into the 

u2 



332 

form of a iimall fiumel; a a the cork,6tiie fdnnel. In cases of 
distillation in which sudden absorption or expanuon may take 
place in tlie retort, this utenwl is fitted into the tubnlure of the 
letort, and the bended part of it, cc,iB filled with wat«r. Then, 
if a vacuum happens to be produced in the retort, the external 
air forces its way through the tube to supply that vacuum ; and, 
on the contrary, if expansion takes place, the elastic fluid gains - 
room by forcing the whole water between c c up 
into the straight part of the tube under the fun- 
nel 6. A number of other uses to which the 
safety tube is applicable, wUl be hereafter de- 
scribed in particular experiments. 

The Woulfe's apparatus ia frequently com< 
posed of a seri.es of bottles, resembling the 
second figure on page 206. In tlib case the 
gas delivering tube from the retort is passed 
through one of the months of the first bottle,and 
made to dip into the liquid which it contains. 
The other mouth of the bottle is provided with a 
tube which does not touch the liquid in that 
bottle, but dips into the liquid in the second 
bottle, and so on. This ^paratus is liable to 
the accidents described above, which, however, 
can be generally prevented by a careful attention 
to the application of heat to the retort. Abetter 
method of guarding against accidents, is to nae 
three necked bottles, and to fix in the middle 
neck of each bottle a tube of 12 inches in length, 
with a top such as is represented in the margin. 
The point b should dip about half an inch into 
the liquid contained in the bottle. Then if ab- 
sorption occurs, common air enters by a c x 6, 
to supply the vacuum produced, while, if expan- 
sion takes place, the half inch of liquid into 
which the tube b dips in the battle, is driven np 
6 X c into the space + +, and the superfluous gas 
escapes at a. It will be perceived that the use 
■of the external tube a++ is to prevent the loss, 
which might be important in an analysis, of the 
half inch of liquid which ia forced up the tube fr 
by the pressure in the bottle. But when tubes 
of this particular form are not at hand, a plain 
tube can he used for the same purpose, the pos- 
sible loss of a little of the liquid being then sub- 
mitted to as unavoidable. 

The tubes which connect the Woulfe's bottles 
together in a distillation of tliis kind, are com- 
monly joined by caoutchouc tubes, as described 
at page 226. 



»-i h, Google 



KANAfiBUSNT OI DABKB. 



WoDLrsa AP?amtu3 for Shall Ezfirihintb. — WlieD it hap* 
pem that & diaUUation effected in the small way, yields both a 
condensable and an incondeowble product, and it ia uecMsary to 




collect for examination the gaa, or incondensable product, as well 

aa the liqiiid product, you can accorapliah that o^ect by em- 
ploving a vessel such as ia represented in the above Bgnre. 
This is a tube retort similar to that already deBcrihed at page 
194, bnt the neck of which, after the iusertion of the charsie, is 
drawn out and bent before the blowpipe into the Ibmi shown 
b^ the figure. The mixture submitted to distillation in this 
vessel is Boiled at the end a. The condensable vapoar which 
it afFords is coaled Into a liquid at the bend 6, in the manner al- 
ready described at pt^e 194. The iocondensablo gas then escapes 
at the mouth c, and ia passed into tube receivers placed in the 



is apparatus is very difficult to clean, it can scarcely be 
used for more than one operation. A more economical contri- 
vance, and one which answers equally well for many experi- 
ments, consists of the tube retort shown at page 194, connected 
hy means of a cork with a small gas delivenng tube. 

CoNQLUDiNo Notice aESPBOTina Gases. 
The student should make himself perfectly master of the in- 
formation relative to the mechanical management of gases here 
given, and accustom himself to transvase common air with skill 
before attempting to work with gases. I caution bim against 

Eutting into operation the experiments of this section, bcibre he 
as acquired some degree of practical knowledge in other branches 
of chemistry. Beginners see so many experiments upon gases 
made during their first visits to the lecture table, and the ex- 
periments are generally of so brilliant a description, that they 
natnrally fall mto the opinion that they must begin their own 
operations with the same subjects. This, however, is a mistake. 
Experiments with gaseous bodies require much more core and 
experience, much more apparatus, and a much greater outlay of 
money, and are attended with more danger and disappointment; 
than tho erperimcntshelonging to many other branches of prac- 
tical chemistry. I would, thereibre, recommend a beginner not t6 
trouble himself with repeating experiments upon the gases, until 
he has been occupied for some time with experiments on solu- 
tion, evtqKnation, crystallisation, neutralisation, precipitation. 



filtration, &o. He will thna acquire tligt experience and llght- 
□eaa of hand, which will qualify him to perfimn more dimeult 
^KperimeDta without risk of foilore. 

It is because I consider the performance of experiments npon 
gases to be comparatively improper work for a young Btndrait 
of chemistry, that I liave treated of the manipnlations relative to 
gasea in an extremely (some may consider reprehensibly) sum- 
mary manner. 1 have been desirouB to make not too large a 
book, but to give in a small compan a compendium of sach in- 
formation, as appeared to me to be best adapted to promote the 
object of those engaged either in learning or teaching the ele- 
ments of practical chemiHtry. On this ground I consider my- 
self fairly warranted in passing over many subjects, however im- 
portant, that did not seem to assist my main object, which is a 
limited object, and not intended to embrace the whole circle of 
chemical knowledge. A complete account of gaseous manipula- 
tion would fill a volume. 1 nave restricted it to a few pages, 
and beg to refer the reader to Dr Faraday's work for longer ge- 
neral descriptions. When, however, I come to treat of the pre- 
rition and examination of particular volatile substances, I shall 
obliged, and it will then too be the proper time, to enter 
into various important details. 



WEIGHING AND MEASURING. 

Wbiohino. — The b^finning and end of every exact chemical 
process consists in weighing ; and the best means of ascertaining 
the we^ht of bodies ia by means of scales, which are therefsic 
indispensable. What are termed apothecaries' acalea, are very 
convenient for students who operate od small quandties, and 
who do not aspire to the utmost degree of accuracy in their first 
attempts. They are put np in a Bttle box, which, besides the 
acales, contuns a series of weights, from half a grain to two 
drachms, in all about 20. These scales are sufficiently acevrate 
for experiments connected with qualitative analysis. The 
charge made for the box complete ia 4s. You must be carefdl 
^ot to use scales, or any other delicate metallic apparatns, In 
any place where acid vapours are flying about; for if you do, 
they will be seriously injured. 

1 have found these apothecaries' scales to possess a high de- 
gree of sensibility. A pair which had been employed in ordi- 
nary operations for several years, and always without the pro- 
tection of a glass case, gave, upon being examined, theibllowing 
results: o turned, when not loaded, with ^ of a grain; 6 turned, 
when loaded n-ith 240 grains in each scJe, with A of a grain. 
The beam can be suspended when in use to the triangle of the 



WBIOBINO AND MXiSnRINO. 235 

retort stand. When not in use, the scales Eire to be kept in their 
box. 

If a student, who lias had some experience in chemistry, 
wishes to have a more sensible balance, he will be obl^ed to 
pay from 30s to 40s for a good one. It is advisable to jrovide a 
D|liaa case to protect sach a balance from damp, or acid fbmn. 
The g:lass case must open only at the sides. A balance adapted 
for use in accurate and important experiments, costs about ;£12 
or £16. 

BeMdesgood scales, accarateweiehta are indispensable. These 
are best mode of brasa, or if Bmall, of thin flattened platinuin 
wire. They should be all grain weights, proceeding from -^ of 
a, grain up to 500 jfmns. A good variety of the small weights 
arc requisite. Thm brass leaf or tin foil, cut into small sups, 
and cryBtalB of pyrope, a clean and very cheap mineral, are very 
useful for counterpoises. A pmr of very small pincers or for- 
ceps, of hrass or iron, should be provided to lift up the weights, 
which ought never to be touched by the fingers, for handling 
is liable to soil them, and affect their weight. These pincers 
answer beat when they have ivory points, 



Every time you are going to weigh, yon ought to hepn by 
examining whether your balance is accurate; and if not, ^ou 
should justify it by putting' a bit of wire or paper into the hght 
scale, of sufficient size to make it counterpoise the other scale. 
The substance to be weighed is placed in one of the scales, and 



weights are placed in the other till the substance is counter- 
poised. Or the Buhatance is first counterpoised, then removed 
from the scale, and weights are put in its place till the balance 



is again in equilibrium ; this method is very good when the a< 
curacy of the balance is doubtful. 

When powders are to he weighed, they ought not to be laid 
on the scale of the balance, but upon a counterpoised watch 
glass, or what is better, npon very smooth glazed paper, the 
edges of which ought to be cut with scissors. The powders may 
be transferred by spatulas formed of platinum, of iron, or of 
paper. Little ivory paper knives answer this purpose very well. 
When crucibles are to be weighed after ignition, they ought 
not to be placed in the scale till sufficiently cool to be handled 
by the fingers. Volatile liquids must be weighed in closed 



= f 



; CiHvjIi: 



WBIOHINQ AND MBASDRINO. 



1 = 3 = 60 

1 = 20 

FRKHCB DECIMAL WEIOBT. 

MUUgramme := 0'01S4 troy grains. 

Cen%ramnie = 0-1540 

Dedgramme = l'S407 

Owmme = 19'4063 

Ms*SDitTRa. — !n a great number of experimeota, It Is neces- 
isry to be supplied with a determinate quantity of a liquid; as, 
for example, an ounce of water. This quantity may be esti- 
mated by means of the balance, but a great deal of time is saved 
by having an instrument by which the ounce of water can be 

^^^ measured. The subjoined figure represents a gra- 

^^B duatedjarfor measuring liquids. This is a cylindri- 
^H cbI glass vessel, which holds, when filled to a certain 
IH mark made near thetop, two ounces of distilled water, 
1^1^ at the temperature of SO" ; that is to say, it holds 
,rf-^^^^ two ounces of clear cold water. It has other marks 

all down it, as low as one drachm; so that any 

quantity of water &om one drachm (or, indeed, the half or 
third of a drachm) to sixteen drachms, may be rewlily obtained 
for any required purpose. An ounce by meanire of any liquid 
is the bulk of an ounce of water. 

Besides tha utility of this uten^ for measuring water, it may 
be also employed, when the purpose does not require great ac- 
curacy, to measure liquids whoso specific gravities are different 
from that of water. If, for example, you wish to obtain an 
ounce of sulphuric acid, vou proceed as follows; — Knowing that 
the specific gravity of sulphuric acid is to the specific gravity of 
water, a little leas than as 2 is to 1 ; and that, consequently, if 
an ounce of water occupies a certain number of divisions In this 
tube, then an ounce of the acid can only occupy a little more 
than half that number; you readily obtain an ounce of sul- 

fhuric acid bv pouring that liquid into the tube till it rises a 
ttle above the mark for J an oz. of water. Vou proceed in 
like manner for other fluids, calculating the bulk according to 
the specific gravity. It is by no means intended, by the re- 
commendation of this manner of measuring liquids In general, 
to do away with more accurate modes; I only point out a mcr 
thod of proceeding calculated to save time in common cases. 

Taeino of Spkoifio Qhavities. 

By the term apecific gravity Is understood the density, or 

quantity of matter under a certdn bulk, of one body, compared 



WBIOHINQ AND UEAfitRINS. 337 

. to the density of another. This latter body is aasnmed as a 
standard, and the Htandard to which bodies are ^nerally com- 
pared ii pure water at the temperature of 60°. la other words, 
specific gravity is the comparative weights of different sort* of 
matter. Having found, by a certain proceas, that a given quan- 
tity of water weighs 1000, we employ the same method to ascer- 
tain the weight of the same quantity of the metal mercury; we 
find it to be 13000; thus we have the comparative weights of 
the same bulk of these two bodies, and we say that the specific ■ 
gravity of mercury is, to that of water, as 13 to 1. If water at 
1000 19 asaumed as a standard of specific gravities, which, as it 
has been said, it generally is, then the specific gravity of mer- 
eury, given with arefetence to the standard, is 18000. Tike 
object of finding the specific gravity of bodies, is to distinguish 
them irom each other in one of their most obvious qualities — 
namely, weight of matter contained in a given space. Students 
of chemistry have frequent occasion to test the specific gravity 
of alcohol, acids, and other hquids, because for many purposes 
these regents require, to bo applied at a particular state of con- 
centration. I proceed to describe the methods by which the 
specific gravities of different kinds of bodies are determined. 

To DETEHHiNB THE 8PECIFJ0 OHAYITV OF A SOLID, it IS Weighed, 

first in air, and then in water. To do this, it is necessary to be 
provided with very accurate scales, to the bottom of one of 
which is aifixcd a small hook, to which the substance is iastcned 
by a fine thread or hair. When the solid, after being weighed 
in the air, is lowered into the water, it loses of its weight a quan- 
tity precisely equal to the weight of its own bulk of water ; and 
hence, by comparing this weight with its total we^:ht, we find 
its specific gravity. The rule therefore is, divide the total weight 
by the hie of weight in water, the quotient is the specific gra- 
vity. Thus, if a mineral weigh 3 ounces in air, and 2 ounces in 
water, and the lolal weight be divided by the lots, which is 1, 
the quotient, or specific gravity of that mineral, will be 3. 

To DEtEHUINE WITS READINESS THE SPECIFIC OHAVITT OP A LlQUID. 

— We use for this the Specific Gravity Bottle. It is a little 
globular bottle, with a flat bottom. It has a glass-ground stop- 
per, with a small hole through it. When the bottle is filled 
with water, or any other Uquid, and the stopper put in its place, 
the superfluous water escapes through the hole, and the bottle 
remains quite full, without any portion of air. A weight to 
counterpoise the bottle must be obtained, made of brass or lead. 



This bottle, when filled with water, contams 600, 1000, 



I number of grains. It is filled with the liquid, the speci- 
fic gravity of which is required, and then weighed with its con- 
tents: the result, deducting the weight of the bottle, is the 
weight of the liquid under examination, which can then he com- 
pared with the weight of water. If, for instance, the bottle holds 
1000 grains of water, and 18C0 grains of sulphuric acid, then the 



Z38 flLASa BLOWINS. 

^eaflcgnritj of the latter ia to that of the fonnw, aa 1860 ia to 

looa 

Students will find it uBeful to use a very thin glaae flask, of 
about half an ounce capacity, and with a long narrow neck, on 
which a mark can be cut, indicating the qpace filled by 200 or 
250 grains of water. This bottle can be employed to ascertain 
the specific gravity of small quantities of acids, alcohol, &c. 

In taking the specific gravitiea of bodies, attention ahonid 
always be paid to their temperature ; because the specific gra- 
Tity of a body when heated is much Icm than the specific gra- 
vity of the same body in a cold state. 

A VBRV BBiDY WAY TO DETEBIIINE THE SPBOIFIC GRiTITT OF BOLIDS, 

is to fill a phial with water, and note the weight of the whole 
accurately in grains. Then to weigh 100 grains of the mineral or 
other substances to be examined, and drop it gradually into the 
phial of vrater. The difference of weight of the phial, with its 
contents now, and when it was filled with water only, will give 
the specific gravity of the matter under consideration. For ex- 
ample, if the bottle weighs fiO grains moTe than it did when 
filled with water odIj, it shows that 100 grains of the mineral 
displace only 60 grains of water, and consequently that its spe- 
cific gravity is 2000, or twice that of water. 



GLASS BLOWING.* 

Thb m<«t eMontial instruments for the practice of this art ore 

the Blowpipe and the Lamp. 

The Comuon Blowpipb.— • Two 
varieties of the blowpipe are em- 
ployed in glass-blowing, the 
simple mouth blowpipe described 
at page 110, and the table blow- 
pipe, worked by bellows. When 
the former is used, it must be sup- 
ported by the tube holder(page 43), 
so as to leave both your huids at 
liberty. The nozile should have a 
pretty large hole. This blowpipe 
can, however, for want of power, 
only be used occasionally in glasa- 
blowmg. 

• A HHuidinbIs porttoD'of thli vlide lanprintcd from the "A>t or Qt,u> 
uiviNa," from the Preorh of " Danger," ft work oT irUrh bat a imiilL InjprFtHuu 
Bi printed, jiud wMch li now fcaTC«. 




OI^RB BLOWING. 



Tablb Bwwpipk. — The conetniction of this appawtns is showH 
by the following diagram- <t is a cylindrical vessel, open at the 
top, and containing water. 6 is a similar vessel, open at the 
bottom, bat provided with a neck at the top. These vessels 




UMy be made of tinplate, but answer better when made of stone- 
wme, because the tinplate is soon destroyed by rust, o is an 
ordinaiy kitchen beUowa, the nnder board of i^ch is fixed in 
a homonfal powtion below the work table, by fillets which cob- 
neot it with the &ame. jr is a round rod of wood, one end of 
which is fixed to the under handle of the bellows, and the other 
end to the under side of the top of the table, in the direction 
shown by the figure. This rod passes through a hole in the 
tipper h^dle of the bellows, but is not attached to it. A coil of 
Strong iron wire (1 inch thick) ia pnt round the wooden rod, 
between the two handles of the bellows, but is not attached 
either to the handles or the rod. A is a string fixed to the appw 
Jiandle of the bellows, passed through a hole in the under handle, 
and fastened at the other end to the treadle ti, e is a leaden 
pipe, affixed to the nozzle of the bellows, and terminating bdow 
the opening of the inroad cylinder b. This end of the pipe 
has a slip of waxed silk tied loosely over it to prevent the back 
preesore of water into the bellows. / ia a leaden pipe fixed air 
tight into the nedc of the cylinder £, and passing upwards 
through a cork fixed in a hole in the table. 

When left at rest, the bellows is kept open by the spring of 
the coiled wire on the rod 7. Theveeeel b is Uien full of water, 
and without air. t 

When the treadle d is forced down by the ibot, the coiled wire 
gives way, the bellows is compressed by the action of the cord ft, 




240 GLASS BLOWING. 

and air ieforced through the pipes into thereeset fi, while the water 
rises in the vessel a, and produces & pressure upon the air in the 
vessel b, Beiteration of this process forces so much air into the 
vessel 6, and bo much water into the vessel a, that the blast 
which issues from the pipe / soon becomes forcible and steady. 
This pipe is provided with blowpipe nozzles, and the jet of air 
is then ready to act upon the flame of the lamp. 

The Glass Blower's Lamp, — It is made of tinplate, of an oval 
OT pear shape, 7 inches long, 1^ inch deep, and provided with a 
shallow tray of somewhat umUar form, but larger size, the use 
of which is to catch overSowing oil. The wick holder is of on 
oval shape, and measures 11 
inch len^hwsys, and } inch 
crosBways. The wick should 
be of clean cotton yam. The 
bestcomhuHtiblelBcIrOfiptnjrs 
qfgweetoU. The wick should 
be kept clean, and cut very 
level, and should be divided 
into two eqoal portions, to 
give a free passage to tho . 
current of air from the blowpipe. This division of the wick is 
best managed by placing a tin partition across the wick holder, 
so as to produce a combmation of two wicks. 

It has been observed that cotton, which has been for some 
time exposed to the air, no longer possesses the good properties 
for which glass blowers esteem it. The alteration of the cotton 
is probably brought about by the dust and water which the air 
always holds in suspension. Such cotton bums badly, forms a 
bulky coal, and permits with much difficulty, the capillary as- 
cension of the hquid which serves to support the flame ; so that 
it is impossible to obtain a good fire, and necessary to be incesr 
eantly occupied in snuffing the wick. Cotton is equally subject 
to alteration when lying In the lamp, even though impregnated 
with oil. You should avoid making use of wicks that are too 
old. When you foresee that you will rem^n a long time 
without having occasion to employ the lamp, pour the oil into a 
bottle, wWch can be corked up, and let the wick be destroyed, 
previously squeezing from it tne oil which it contains. 

It is indispensable to make nse of none but new and good cot- 
ton ; it should be clean, soft, fine, and not twisted. It is best 
to preserve it in boxes, after having folded it in many double 
papers, to exclude dust and moisture. When you wish to make 
wicks, take a skein of cotton and cut it into four or six pieces, 
die^wse them side by side in snch a manner as to make a bundle 
more or less thick, and e^ht or ten inches in length ; pass a lairge 
comb lightly through the bundle, to lay the threads even, and 
tie it gently at each end, to keep the threads from getting en- 
tangled. 



OLASS BLOWING. 241 

A wick of the size here prescribed should tiae | of an inch — 
never more than an inch— above the surface of the oil. 

When you have the command of gas, the burner repre- 
sented at page 114 will be found useful. The neck a of this 
burner fits most common gaa sockets prepared for single jets. 
When this burner is used for glass blowing, the point + must be 
turned towards you, and the point c farthest away, so as to place 
the orifice + c in a line before you. 

Jets or Nozzles. — The point of your blowpipe should be form- 
ed in snch a manner tliat you can fix upon it various little jets, 
or nozzles, the oriAccB in which, always perfectly round, ought 
to van' in size according to the hnlk of the flame upon which 
you desire to act. The best way to manage this ia to let the 
pipe / (page 239} terminate at tne surface of the table, and to 
attadi to it a bent brass tube such as is shown in the wood cut 
which represents the lamp, page 240, the upper opening of which 
brass tube should spread a bttle outwards, to faciUtate the adjust- 
ment of small nozzles by the intermediation of soft paper or corks. 

You cannot, without this precaution, obtain the maximum of 
heat which the combustion of the oil is capable of affording. 
This employment of little moveable jets offers the facihty of es- 
tablishing a current of air, greater or smaller, according to the 
object you wish to effect ; above s!I, it allows you to clean with 
ease the cavity or oriiice of the beak, as often as it may be ne- 
cessary. 

These jets con he made of different materials. It is most ad- 
visable to have them made of copper or brass ; those which are 
formed of tin plate (white iron), and which are commonly used 
in chemical laboratories, are the worst kind of all. They soon 
become covered with grease or soot, which either completely 
closes up the orifices, or, at least, very soon alters the circular 
form which is necessary to the production of a good fire. Glass 
jetj! are less liable to get dirty, and are much cheaper than the 
above; but, on the other hand, they have the disadvantage of 
being easily melted. This can to a certain extent be remedied 
by making the points of very thick glass, and by always keep- 
ing them at some distance from the flame. Moreover, aa you 
can make them yourself when you are at leisure, theit use is 
very commodious. 

Another method of affixing jets to the hydrostatic blowpipe^ 
may be that described at page 1 10, in reference to the mouth 
blowpipe. The leaden pipe /, p^e 239, may be soldered U 



brass pipe c, page 110, and the latter be capped by such jets aa 
<f, page 110. 'file pipe / may, aa I have said at page 239, pass 
up through a hole m the table, and be fixed in that hole by a 



cork; or, where it is not expedient to perforate the table,' the 
pipe may be steadied by being tied to a wooden clamp screwed 
to the edee of the table, — the bellows and blowpipe being u 
that case fitted together, but not fixed to the table. 



24S GLABS BLOWIKO. 

Of whatever mftteml the beak may be made, its orifice mtut 
be perfectly round, and the tize of the orifice, as I hare before 
observed, must have a relation to the size of the wick which is 
to be twed with it. The diameter of the orifice of the jets best 
adwted for use with a wick of the eixe pretcribed above, ii the 
twei/thofanitich. 

When soot is departed oo a giass jet, yon mngt replace it by 
a, new jet, and then clean it l^ liumiug off the soot in the flame ; 
but you must take care not to let the glass get softened durine 
the cleaning, otherwise the jet wilt be spoilt, for a sharp weU 
defined orifice is indispensable to the production of a good name. 

Mbahs of Oftaikino a Gooo Flame.-— It is only by long habi- 
tude, and a species of routine, that workmen come to know, 
not only the kind of flame which is most proper for each object 
they wish to make, bnt the exact point of Hie jet where they 
ou^t to expose their glan. 

When the oij^ce of the blowpipe is somewhat large, or when 
(the orifice being capillary) the current of air is Tery strong, or 
the beak is somewhat removed frora the flame, the jet al fire, 
instead of lieing prolonged into a pointed tongue, is blown into 
a brash. It makea then a roaring noise, and ffl>reads into an ir- 
regular figure, wherein the different patta of the flame are con- 
founded beyond the posBibility of discriminatinn. Tliis flame is 
very pToper for workiug glaae tubes ; it ought to be clear and * 
very brilliant, and above ^, it should not deposit soot upon cold 
bodies suddenly plouged into it. The mtunmutn of temperature 
in this flame is not well marked ; I may say, however, that in 
general it will be found at about two-thuda of the whale length 
of the flame from the jet. As this roaring flame contains a 
great quantity of carburetted hydrogen, and even of vapour of 
oil, escaped from combustion, it possesses a disoxidiong or re- 
ducing property in a very high degree. 

The lamp would be finuy seated upon a steady and per- 
fectly horizontal table, and snonld be kept continuallv full of 
oil. The oil which escapes during the operation, from tne lamp 
into the tin stand placed below it, should be taken up with a 
glass tube having a large bulb, and returned to the lamp. 

When you set to work, the fint thing you have to do is to ex- 
amine the orifice of the beak. If it be closed, or altered in form, 
by adhering soot, you most carefully clean it, and open the canal 
by means of a needle or fine wire. In the next place, yon 
freshen the wick bv cutting it square, and canriug off with the 
•cisBOrs the parts that are carbonised. You then divide it into 
two principal bundles, which you separate suflldentlv to permit 
a current of air, directed between the two, to touch their surfiaee 
lightly, without being interrupted in its progress. By pushing 
the bundles more or less close to one another, and by snufling 
them, yon arrive at lengi:h at obtaining a convenient flame. It is 
a good plan to allow, between the two principal bundles and at 



243 

(heir inieiior part, a little portion of the wick to remain: yoa- 
ieni thia down in the direction of the jet, and make it lie imme- 
diately beneath the current of air. When you once get a Kood 
flame, you take particular care not to alter the position of the 
lamp or blowpipe, for everything depende npon this position, 
and a hair's breadth of alteration often makes or mars a good 

The wick must be prevented &om touching the rim of the 
lamp, in order to avoid the running of the oil into the etand of 
the lamp. This is easily manned by means of a bent iron wire, 
brought down round the wick and level with the surface of the 
lamp. A few drops of oil of turpentine spread upon the wick, 
makes it take hre immediately over its whole extent, on the ap- 
proach of an inflamed aubatance. 

To obtain a good flame, it is necessary to place the lamp in such 
a position that the oriflce of the blowpipe shall juat touch the 
exterior part of the flame. The beak must not enter the flame, 
as it can then throw into the jet only an incon^erable portion 
of the ignited matter. On the other hand, if the lamp he too far 
away from the blowpipe, the flame becomes trembling, appears 
blueiah, and possesses a very low degree of heat. 

The flame should be directed upwards at an angle of 20 or 25 
degrees, as exhibited by the cut at page 240. 

The current of air ought to be constant, uniform, and sufiicient- 

. ly powerful to carry the flame in its direction. The point to 

which you should apply, in the use of these instruments, is to 

enable yourself to produceacurrent of air so uniform in its course 

that the projected flame be without the least variation. 

Finally, when you leave off working, yon should extinguish 
the flame by cutting off the inflamed portion of the wick with 
the scissors. This has the double advantage of avoiding the pro- 
duction of a mass of smoke and of leaving the lamp in a fit state 
for another operatioik 

Places Fir to Work in. — Every place k adapted for a work 
shop, provided it be not too light and the air be tranquil. The 
light of the lamp enables one to work with more safety than 
day light, which does not permit the dull red colour of hot glass 
to be seen. Currents of cold air are to be avoided, because they 
occasion the fracture of glass exposed to them on coming ont of 
the flame. 

Choice of Olasb Tubes. — The only materials employed in the 
fabrication of the objects described u this treatise, are tubes of 
hard glaas or of flint glass. They can be had of all diameters, 
and of every variety of thickness. They are commonly about 
three feet long, but some are found in commerce which are six 
feet in length. You should choose tubes that are very uniform 
— that is to say, straight, and perfectly cylindrical, both inside 
and outside. A good tube should have the same diameter from 



244 ai 

one end to the other, and the sides or substance of the glass shonld 
be of equal thickness in every part. This is indispensable when 
the tubes are to have spherical bulbs blown upon them. 

The substance of the glass should be perfectly clear, withont 
hlebs, or specks, or stripes. The tubes ore so much the more 
easy to use, as tiie glass of which they are made ia tlie more ho- 
mogeneous. Under this point of view, the white glass, known 
in commerce by the name of crystal or flint glass, is preferable 
to hard glass : it is more fusible, less fragile, and leas liable 
to break under the alternations of heat and cold : but it is dearer 
and heavier, and has the serious disadvantage of becoming per- 
manently black when exposed to a, certain part of the flame. 
. The best hard white glass tubes are made in Bohemia. 
They are formed of potash and lime in combination with 
silica. The best soft white glass tubes are made in France. 
They consist of soda in combination with silica. Both of 
these sorts are &ee from lead. In England, it is seldom poB- 
uble to get made any other sort of glass tubes than those of 
flint glass. Chemists have therefore to import tubes for experi- 
uental purposes from the continent, as it rarely happens that 
flint glass tube vessels can be employed with confidence or suo- 

You must take care never to employ fiint glass for inatro- 
ments which are to be submitted to the action of certain 
fluids—such as sulphuretted hydrogen, and the hydro-sulphu- 
rets ; for these compounds are capable of decomposing flint 
glass, in consequence of its contaming oxide of lead. In ^ 
neral, hard German glass is preferable to flint glass for dl m- 
Btruments which are to be employed in chemistry. Flint glass 
should only be used for ornamental objects, and for barome- 
ters, thermometers, and other instruments employed in pliiloso- 
phical researches. 

Peiepabation of Tubes before hea.tiko them. — Before present- 
ing a tube to the flame, you should clean it well both within and 
without, in order to remove all dust and humidity. If you 
neglect to take this precaution, you run the risk of cracking or 
staining the glass. When the diameter of the tube is too small 
to permit of your passing a plug of cloth or paper to clean its 
interior, you can accomplish the object by the introduction of 
water, which must, many times alternately, be sucked in and 
blown out, until the tube is deemed cleau. One end of it must 
then be closed at the lamp, and it must be gradually exposed to 
a charcoal fire, where, by raising successively all parts of the 
tube to a sufficientiv high temperature, you endeavour to volati- 
lise and expel all the water it contains. In all cases you consi- 
derably Ikcititate the disengagement of moisture by renewing the 
Bjr in the tube by means of a bottle of Indian rubber fastened to 
the end of a long narrow tube, which you keep in the interior of 
the tube to be dried during the time that it is being heated. 



OLA SB BLOW IN a. 245 

Yon can here advantt^eously substitute alcohol for water, as 
being much more volatile; and as dissolving greasy matters ; but 
theM methoda of cleansing should only be employed for valuable 
objects, because it is extremely difficult fully to expel moisture 
from a tube wherein you have introduced water, and because al- 
cohol is too expensive to be employed where there is no particu- 
lar necemity. 

When the tubes no longer contain dust or moisture, you mea- 
sure them, and mark the divisiona according to the sort of work 
which you propose to execute. 

8[iEs OP Glass Tubes — It may be useful to give cross sec- 
tions of the most usetul sizes of glass tubes, with notices of the 

chemical vessels, or parts of vessels, for which they best answer. 
Here they are : 

1 9 s ( I e T 

oooOOOO 

» 9 ID II II 

OoOoo 

Nob. 1 to 5. Hard. Oosed sabliming tubes for arsenic and 
other volatile substances, pages 104, 132. Open subliming 
tubes for use with the blowpipe, page 160. Little matrasses 
for the sublimation of water, cage 10, &, page 106, i. 

Nos. 1 to 5. Soft. Gas delivering tubes, pages 194 and 203. 
Dropping tubes, page C8. Tube funnels, page 15. 

Sos. 6, 7, 8. Sard. Test tubes, page 8, c, page 10, page 
49. Bulb tubes, p^ 8, a, b. Tube retorts, pages 193 and 206. 

Nos. 6, 7, 8. Sojl. These also can be used for test tubes, 
but very rarely can be procured sufficiently thin is the glass, 
to answer so well as the hard tubes. Strong tubes of these 
siaes, and 2 or 3 inches long, sealed at one end, and bordered 
at the other, are very useful as bottles for the preservation 
of small quantities of valuable substances. Nos. 6 and 7, serve 
for the wide part of dropping tubes. 

Nob. 8,10. So/t. Coopers Gas Heoeiver, page 219. Dry- 
ing tubes for gases, page 224. Bent gas receiver,- page 220. 

Nos. 9, 12, Hard. For the preparation of bulb retorts, page 
10, and 200, and for bulb decompo^g tubes, page 227- 

Nob. 9. Sqfl. Bnlb tubes and retorts for boiling liquids in, 
x3 

..oogic 



246 OLAsa Bi/iwiNO. 

but not for preparing gases, or for any case of exposure to high 
temperature with d^ chaif^ in them. 

Nos. 7, 8, 10. Hard. Tubes for organic analysis by com- 
bustion with oxide of copper. Tube retorts, page 206. 

No. 10. Soft. Conoensing tubes of the I^ge distiUing or 
rather cooling apparatus, page 201. 

No. 11. Soft. Gas delivering tubes for ordinary use. This 
size makes a pretty substantial tube. It also serves for strong 
stirrers when closed at the ends, page 48. 

Nos. 7, 8, 9, 12. .Si;^. Oaa receivers to be used with the 
mercury trough, page 218. They should be C inches lonj;, 
sealed at one end, and ground flat at the other, so as to be capable 
of being closed by the pressure of a finger. 

Mktbod or Pkesbntiho Tubes to the Flaue ahp or Work- 
INO THBk TiiEFtEiK. — The two OTms are supported on the front 
edge of the table, and the tube is held with the hands either 
above or below, according as It may be necessary to employ 
more or less force, more or less lightness. You ought, in gene- 
ral, to hold the tube horizontaUy, and in such a manner that 
its direction may be perpendicular to that of the flame. Yet, 
when you wish to heat at once a large portion of the tube, or 
to soften it so that it shait tank together in a particular man- 
ner, as in the operation of sealii^, you will find it convenient 
. to incline the tube, the direction of which, however, must 
always be such as to turn the heated part continually towards 
you. 

I am about to give a general rule upon the observance of 
which I cannot too strongly insist, as the success of almost 
every operation entirely depends upon It. The rule is, never 
to preg^ a tube to the flame mthout continuat.ly turnino it; 
and turning it, too, with such a degree of rapidity that every 
part of its circumference may he heated and sonened to the 
same degree. As melted glass necessarily tends to descend, 
there is no method of preventing aheated tube from becoming 
deformed hut that of continually turning it, so as to bring the 
softened part very frequently uppermost. When you heat a 
tube near the middle, the movement of the two hands must be 
vniform and timultaneout, or the tube will be twisted and 
spoiled. 

When the tubes have thick sides, they must not be plunged 
iuto the flame until they have previously been strongly heated. 
You exjpose them at first to the current of hot au" at some 
inches from the extremity of the jet; you keep them there 
some time, taking care to turn them continually, and then you 
gradually bring them towards, and finally into, the flame. 
The thicker the sides of the tubes are, the greater precaution 
must be taken to elevate the temperature graduaUy : this is 
the only means of avoiding; the fractures whii^ occur when the 
glass is too rapidly heated. Though it is necessary to take sq 



OLASB BUIWIMQ. 247 

much care with large and thick tuhea, there are, on the con* 
trorv, some tubes so small and so thin that the moat sudden 
application of the fire is insufficient to break them. Practice 
Boon teaches the rule which is to be followed with regard to 
tubes that come between these extremes. 

Hard glass ought to be fused at the maximum point of 
heat ; but glass that contains oxides capable of being reduced 
at that temperature (such as flint glass) requires to be worked 
in that part of the flame which possesses the highest oxidating 
power, li you operate without taking this precaution, you 
run the risk of decorapoaing the glass. Thus, for example, 
in the case of flint gla^ you may reduce the oxide of lead, 
which is one of its constituents, to the state of metallic lead. 
The consequence of such a reduction m the production of a 
black and opaque stain upon the work, which can only be re- 
moved by exposing the glass, during a very long time, to the 
extremity of the jet. 

You must invariably take the greatest care to keep the flame 
from passing into the interior of the tube ; for when it gets 
there it deposits a greasy vapour, which is the ordinary cause 
of the dirt which accumulates in inHtruments that have been 
constructed without sufficient precaution as to this matter- 
In order that you may not blacken your work, you should 
take care to snuff the wick of the lamp whenever you per- 
ceive the flame to dnmsit soot. 

You can judge of the consilience of the tubes under opera- 
tion as much by the /e^ as by the look of the gloss. The 
degree of heat necessary to he applied to particular tubes, de- 
pends entirely upon the objects for which they are destined. 
As soon as the glass begins to feel soft, at a brownieh red heat, 
for example, you are at the temperature most favourable to good 
bending. But is it intended to bloin a bulb ? The glass must, 
in this case, be con^letely melted, cmd subjected to a full 
reddish white heat. I shaU take care, when speaking here- 
after of the different operations to be performed, to mention 
the temperature at which each can be performed with most 
success. 

When an instrument upon which you have been occupied, is 
finished, you should remove it from the flame gradually, 
taking care to turn it continually, until the glass has acquir- 
ed sufficient consistence to support its own weight without be- 
coming deformed. Every instrument formed thus of glass re- 
quires to undei^ a species of annealing, to enable it to l>e 
preserved and employed. To give the instrument this anneal- 
ing, it is only necessary to remove it from the flame very 
gradually, allowing it to repose some time in each cooler place 
to which you succesaively remove it. The thicker or the more un- 
equal the sides of the glass, the more carefully it requires to be 
annealed. No instrument should be permitted to touch cold 
or wet bodies while it is warm. 



248 QL 

FuKDAHBm'&i, Opbbations in Glabs BLowrso.— All the modifi- 
cations of shape and size which can be given to tubes in the 
cwnstniction of varions instrDineiitB, are prodnced by a vety 
small nninber of disainiilar operations. I hare thought it best 
to unite the description of these operations in one article, both 
to avoid repetitions and to place those who are desirous to exer- 
cise this art in a state to proceed, without embarrassnient, to the 
construction of any instrument of which they may be prorided 
with a model or a drawing ; for those who attend properly to 
the instructions given here, with respect to the fundamental 
Operations of glaai blowing, will need no other instructions to 
enable them to succeed in the construction of all kinds of inatra- 
ments that are capable of being made of tubes. These funda- 
' ' ' ' ' ■ ■ I, which may be named 



1. Cutting. 
3. Bordering. 

2. Widening. 



7. Bloning. 
a. Piercing. 
9. Bending. 
10. Soldering. 



I. Dnwi 

6. Choking. 

I proceed to give a detailed account of these different operations. 
1. — Glass Cuttino. 

The different methods of cutting glass tubes, which have been 
contrived, are all founded on two principles; one of these is 
the division of the surface of glass by cutting instrumenta, the 
other the effecting of the same object by a sudden change of 
temperature ; and sometimes these two principles are combined 
in oas process. 

The first method consists in notching the tube, at the point 
where it is to be divided, with the 

^ — -. edge of a Lancashire crossing file, 

^ — -■ — ' or with a thin plate of cast steel 

having a rough edge prepared by 

rubbing it on asandstone or a sanded board. The nails of the two 

thumbs are then placed against the cut 

^jj. jga- in the tube, but upon the opposite side 

— Iu^^gtfj7^r= '^^ ^^ tube, the cut being turned Jrom 

<*i>j tii*' you, and at the same instant the two 

ends of the tube are pulled asunder, 

while the thumb nails are pressed against -the tube opposite to 

the notch. This method is sufficient for the division of small 

tubes, such as Nos. 1 to 6, page 245. Larger and thicker tubes, 

Nos. 7 to 10, need to be sawed into by the steel blade; and when 

they are very thick or la^e, the notch requires to be q 

even half way round the tube. You can also employ a f '' 

wire stretched in a bow, or, still better, the glass cutter!^ 

with eitlier of which, assisted by a mixture of emerv ancM 

you can cut a circolar trace ronnd a large tube, and thenV 



OLASa BLOWING. 249 

When the pottioa which is to be remoTed from a tube is so 
Biuall that you «umot easBy lay hoU of it, you cut a notch with 
s file, and expose the notch to the point of the blowpipe flame : 
the cut then flies round the tnbe. 

This brings us to the second method of cutting tubes — a tnetiiod 
which has been modified in a great variety of ways. It is founded 
on the property possessed by vitrified matters, of breaking when 
exposed to a sudden change of temperature. Acting upon this 
principle, some artists apmy to the tube, at the point where they 
desire to cut it, a band of fused glass. If the tube does not im- 
mediately separate into two pieces, they gire it a, alight smart 
blow on the extremity, or thev drop a little water on the heated 
ring. Other glass blowers make use of a piece of iron heated to 
redness, an angle or a comer of which they apply to the tube at 
the point where it is to be cut, and then, if the fracture is not at 
once effected by the action of the hot iron, they plunge the tube 
suddenly into cold water. 

The two methods here described can be combined. After 
having made a notch with a file, or the edge of a flint, you in- 
troduce into it a little water, and bring close upon it the point 
of a very little tube previously heated to the melting point. 
This double application of heat and moisture obliges the notch 
to fly right round the tube. 

You may cut small portions from glass tubes in a state of fn- 
aion, by means of common scissare. . . 

The necks of the large retorts and flasks are cut off by means 
of- a ring of iron fastened to the end of an iron rod, several of., 
which rings of various sizes should be found in a laboratory. A 
ring of the proper size for the object being chosen, it is brought 
to a full red heat, and stuck upon the neck which is to be cut. 
After a minute, it is taken off and a few drops of cold water or a 
wet stick is applied to the heated glass; upon which the neck 
immediately flies ofl'. 

Another and better method of cutting off the necks of thick 
glass vessels, is by means of jxatile glass cutters, which are pre- 
pared as follows : Take of gum arable Ipart, of gum tragacanth 
Ijpart, and digest them in hot water till yon obtain a slimy mass. 
The mixture must make 10 parts. Add J part of gum benzoin 
dissolved in the smallest possible quantity of alcohol, and 10 or 
12 parts of extremely weU pulveriaed charcoal. Mix the wh<de 
intimately together, work the mass into a stiff paste, roll it be- 
tween two boards rubbed over with charcoal powder, into cylin- 
ders j inch thick and 8 inches long, and let tnem dry. 

It is of importance to have the charcoal thoroughly pulverised 
and sifted, and well kneaded with the other ingredients. 

These pastile glass cutters when heated at one end, continue 
to bum uke an ordinary fomigating psstile, producing a red- 
hot point, by means of which a crack in a glass can be led in 
any direction with as much certainty as a line can be drawn with 
a pen. When the glass that is to be cut has no crack, it is no- 



250 QL 

ceggaiy to make a acntch with a file, and then Hpring it opeu by 
^proximatine the heated pastile. When ;□□ wish to cut off the 
' neck of a flask boss to obtain both piectsof the veaaelin an no- 
broken state, or when you wish to cut a flask acroea the middle 
without firat commencmg at the edge and so briugiug down a 
vertical split, you obtain yonrobject by first making a scratch or 
cut on the flask with a £le, in the direction of the desired frac- 
ture. You then hold the lighted pastile cloae to the glass, and 
St a little distance (the eighth of an inch) from the end of the 
scratch, and in the directiim in which you wish the split to be 
extended, and you push the pastile slowly towards the scratch till 
the split takes plat^, which generally is to the extent of the heat- 
ed portion. You then again remove the pastile to the eighth of 
an inch &om the end of the split, and again push it towards the 
split; upon which a second extension takes place. The same 
operation can be repeated till th» split has taken the whole 
course you desire it to do. It is useml to make an ink line, or 
to tie a thread round the vessel, to guide the pastile in a right 
line. With a little exercise yon will become able to cut glass in 
this manner as strmght and as neatly as by the use of a rule and 
diamond. When the pastile ia finrt lighted it must be allowed 
to bum to a point lieibre you attempt to cut glass with it. When 
you have finished your operation, you extioguish the £re by 
plunging the pastile into dry sand. 

How TO Bore Holes in Glass. — Hard steel tools, such as 
drills, files, rasps, &c., cut glass with extraordinary facility 
when thoroughly wetted with a solution of camphor in oil of 
turpentine. With a sharp three edged drUl, and a drill bow, 
holes can be bored easily, and still better when the drill is fixed 
OD a lathe, SB rapid motion is useful. The drill can nevertheless 
be eflfectively used by the hand alone, but an abundant supply 
of the camphorised oil of turpentine tnust be applied to the 
cnttiog toot during the operation. In the same manaer, a hole, 
when once made, can be readily enlarged by a round file, the 
ragged edges of tubes or glass plates can be removed by a fiat 
fi^ female screws can be cut in thick plates of flint gliuB, flat 
window glass can be sawed by a saw made of a watcn spring; 
and, in ^ort, glass, brittle and refractory as it is, yields so ef- 
fectually to the action of camphorised oil of turpentine, as to 
prove umoat as readily worl^ble with cutting tools as biosa 
Itself. 

2. BOBDERING. 

To whatever use you may destine the tabes which you cut, 
they ought, almost always, to bo bordered. If you merely de- 
sire that the ei^es shall not be sharp, you can smoothen them 
with the file wetted with camphoriSed oO of turpentine, or, 
what ia better, you can expose them to the flame of the lamp 
until they are rounded. If you fear the sinking in of the edges 
when they are hi a softened state, you can hinder this by work- 
ing in the interior of the tube a round rod of iron, one-sixth of 



0LA8B BLOWING. 25t 

an inch thick; and one end of which should he filed to a coni- 
cal point, and the othw end be inserted into a thin, round, 
wooden handle. You will find it convement to have a umilai 
rod with a slight bend in the middle. 

When you desire to make the e^ea of the tube pnjecL 
bring the end to a Boft state, then insert in it a metallic rod, and 
move it about in such a manner aa to widen a httle the opening. 
While the end of the tube is still soft, place it suddenly upon a 
horizontal surface, or press it by means of a very flat metallic 
plate. The object of this operation is to make the end of the 
tube flat and uniform. The metallic rod which yon employ 
may be the same as I have described in the preceding paragraph. 
Instead of agitating the rod in the 

tube, you may hold it in a fixed . 31 

oblique position, and turn the tube ( ,,ij|m 

round with the other hand, taking WJ. 

care to press it continually and regu- v, 

larly against the rod. See the figure. w. 

Very small tubes can he bordered by « 

approaching their extremities to a 

flame not acted upon by the blowpipe; particularly the Same 
of a spirit lamp. 

The edges of flasks and of thick tubes con be most readily 
bordered by means of a stick of hard and well burnt charcoal, 
cut into the form shown by the mar- 
ginal figure, and having both a blunt 
point and a narrow point, to suit open- 
mgs of different sizes. 
When the edges of a tube are to be rendered capable of Buf- 
fering considerable pressure, you can veiy comaderably augment 
their strength by soldering a rib or string of glass all round the 
end of the tube. Holding the tube in the left hand, and the 
string of glass in the right, you expose them both at once to the 
flame. When their extremities are sufGcieutly softened, von 
attach the end of the rib of glass to the tube at a very short 
distance from its extremity; von then continue gradually to 
turn the tube, so as to cause the rib of glass to adhere to it, in 
proportion as it becomes softened. When the rib has made 
the entire circumference of the tube, yon separate the surplus 
by suddenly darting a strong jet of fire upon the point where it 
should be invided; and you continue to expose the tube to the 
flame, always turning it round, until the ring of glass is fully 
incorporated with the glass it was applied to. You then re- 
move the instrument from the flame, taking care to simeal it in 
so doing. During the operation, yon must take care to prevent 
the sinking tJDgether of the udes of the tube, by now and then 
turning the iron rod in the interior. It is a rtdhml, or adfwm- 
t«A red heat that is best adapted to this operation. 



I , Google 



S52 OLASa BLOWINO. 
3. WiDSBINO. 

When you desire to enlai^ the diameter of the end of a tube, 
it is necessary, after having brought it to a aofi state, to remove 
it from the name, and to press the sides of the glaaa outTrardg by 
meansof alorgetDdof iron with 3 conical point. The tube most 
be again heated, and again pressed with the conical iron rod, 
ontil the proper enlargement is effected. This operation is much 
the same as that of bordering a tube with projecting edges. 
4. — Da*.wiNo OtT. 

You can drain out ot contract a tube either in the middle or 
at the end. Let us in the first place consider that a tube is to 
be drawn out in the middle. If the tube is long, you support it 
with the right hand beUm)^ and the left band oAotre, by which 
means you secure the force that is necessary, as weU as the posi- 
tion which is commodious, for turning it continuallv and uni- 
formly in the flame. It must be kept in the jet till it has ac- 
quired a cherry red heat. Yon then remove it from the flame, 
and always continuing sen tly to turn it, you gradually separate 
the hands from each other, and draw the tube in a sfraight line- 
In this manner you produce a long thin tube in the centre of the 
original tube, which ought to exhibit two uniform cones where 
it joins the thin tube, and to have the points of these cones in the 
prolongation of the asisof the tube. 



>=<: 



To draw out a tube at its extremity, yon heat the extremity 
till it is in fusion, and then remove it from the flame; you im- 
mediately seize this extremity with the pliers, and at the same 
time separate the two hands. The more rapidly this operation 
is performed, the glass being supposed to be well softened, the 
more capillary will the drawn-out point of the tube be render- 
ed. Instead of pinching the fused end with the pliers, it ia 
simpler to bring to it the end of a httle auxiliary tube, which 
ahould be previously heated, to fiise the two together, and then 
to draw out the end of the original tube by means of the auxili- 
ary tube. In all cases, the smaUer the portion of tube softened, 
the more abrupt is the part drawn out. 

When you desire to draw out a point 
from the side of a tube, you must heat 



that portion alone, by holding it fixedly 
at the extremity of the jet of flame. 
When it is sufficiently softened_, solder to 
it the end of an auxiliary tube, and then 
draw it out. The annexed figure ex- 
hibits an example of a tube drawn out 
laterally. A red heat, or a cherry red/iealy 
is best ad^ted to this operation. 




353 



5. — Chokino. 



I do not mean by choking, the closing or atopping of the 
tube, but uinply a dimination of the interior passage or bare. 
It ia a sort of contraction. You perform the operation by pre- 
Benting to tiie flame a zone of tbe tube st the point where the 
contraction ia to be effected. When the glaas is softened, you 
draw out the tube, or puah it together, according as yon dedre 
to produce a hollow in the surface of the tube, or to hare the 
surface even, or to cause a ridge to riae aboTe it. A cherry red 
keat ia the proper temperature to employ. 
6. — Sealiho. 

Kthe Bides of the tube to be scaled are thin, and its diameter 
is small, it is sufficient to expose the end that you wish to close 
to the flame of the lamp. When the glass is softened it sinks 
of itself, in consequence of the rotatory motion giren to it, to- 
wards the axis of the tube, and becomes rounded. The appli- 
cation of no instrument ia necessary. 

If the tube is of considerable diameter, or if the sides are thick, 
you must soften the end, and then, with a metallic rod or a flat 
pair of pliers, mould the sides to a hemisphere, by bringing the 
circumterence towards the centre, and continuing to turn the 
tube in the flame, until the extremity is well setJed, and per- 
fectly round. Examples of the figure are to be seen in fig. c, 
page 8, and fig. a, page 10. Instead of thia method, it is good, 
when Uie extremity is sufficiently softened, to employ an auxi- 
liary tube, with the help of which you can abruptly draw out 
the point of the original tube, which becomes by that means 
cut and closed by the flame. In order that thia part may be 
well rounded, you may, as soon as the tube ia sealed, close the 
other extremity with a little wax, and continue to e:^ose the 
sealed part to tne flame, until it has assumed the form of a droft 
'o/laHotr. Fig. 6, page IIM. You can also seal in thisfoahion, 
by blowing, with precaution, in the op^i end of the tube, while 
the sealed end is in a softened state. 

If yon desire the sealed part to be flat, you must press it, 
while it is soft, against a flat substance. If you wish it to bo 
concave, like the bottom of a bottle, you must suck air from the 
tube with the mouth j or, instead of that, force the softened end 
inwards with a metallic rod. You may also draw out the end 
till it be conical, as figs. 4, 6, page 104, or terminate it withalit- 
tlc button. In some cases the aeal^ end is bent laterally, as 
fig. 4, page 104 ; in others it is twirled into a ring, having pre- 
viously been drawn out and stopped in the bore. In short, the 
form given to the sealed end of a tube can be modified in an in- 
finity of ways, accordbg to the object for which the tube may 
be destined. 

In preparing test tubes like fig. c, page 8, yon begin by cut- 
ting the long glass by means of the pastile cutter, into lengths 
eqoil to two tubes. Yon then draw ovt each of these pieces of 



a LAM BLOWIMQ. 



tube in the middle, w as to produce a short narrow tube b a. 
If the glass at a is now held steadily in the flame, and the piece 






pnlled aw»7, the other tobe melts toaetber at a. TMa 
sd end is then turned in the flame, till it beoomes nniferml]' 
round and thick. 

Yon should take care not to accmnnlBte too mnch glsM at 

the place of sealing. If you allow it to be too thick there, yon 

run the riak of seeing it crack during the cooling. The opera- 

tioB of seeling succeeds best at a cherry rtd heat. 

7. — BLDiriNo. 

The construction of a great number of pluloeophlcal instraments 
requires that he who would loake them should exercise hima^ 
in the art of blowing buib» poss a wing a figure exactly qdierieaL 
This is one of the mo«t difficult operatioos «f the art. 

To bk)w a bulb at the eztraaiity <^ a tube, yon commence by 
sealing it; after which you c(dlect at the sealed extremity more 
ur leae glass, according to the size and the st^iditT which vou de- 
sira to give to the bulb. When the eoA of the tube is made thick, 
completely sealed, and well roouded, you elerate the tempaia- 
ture to a reddith whtU heat, taking care to turn the tube contin* 
uallr and nf>idjy betweMk your bigeis. When the tad b p«r> 
fectly soft, you muare it from the fiavw, nd, holdnig the tube 
hwizontally, you blow quickly witit the mouth into the op«a Nid, 
without discontinuBg for a esBglemomesit the moraoeat of rotk- 
tion. If the bulb does not by this operation acquire the neees- 
saiy size, jron eoftra it again in the flame, while wtder the ac- 
tion of which yon turn it very rapidly, lest tt sink together at 
th« aides, and become deformed. When it is sufficiently softened 
you introdnce, in the same manner as before, a ireait quaatity 
6f air. It is of importance to obeerre that, if the tube be of 
large diameter, it is neceewuy to contract the end bj which y 



When the bolb which you detdre to make is to b« semawhat 
large, it is necessary, after having sealed the tube, to soften itibr 



hich you 
h laejlity 

emawhat 
large, it is necesHoy, after having sealed the tube, to soften itibr 
the ^>ace of about half an inch from its extzemity, tud then, witli 
theaidof a fiat piece of metal, to press modcxitMy and repe^ciUy 
on the softened po^on, until the sidesofthe tube whidi are thus 
pressed upon, sink together, and acquire a orrtaia d<^;ree of thick- 
nsse. During this operation, hewerer, yon omet take care to 
blow, now and th^ into the tube, in order to retain a hollow 
space in the midst of the little maas of glass, and to hinder the 
bore of the tube from beroK closed up. Whcoi yen hare tins, 
at the expense of the lei^th of the tube, aeeuv^ted at its nc- 
tremity a quantity of glaa sufficient to produce a bnlh, yon have 



0LA«8 BLOWING. S5S 

nothing more to do than to heat the matter till it is rdsed to a 
temperature marked by a reddUh white colour, and then to ex- 
pand it by blowing. 

Instead of aocumolating the gldn tiuis, U v> more eiqiiadietit to 
hlow on the tube a eeries lA little bulbe doee to one another, and 
then, by beating the intervals, and blowing, to aut« these mtle 
bolbe into a larg^ one of convenient dimensionB. 

I have already obaerred, and I repeat here, that it ia indispen- 
oably neeeeaary to hold the glass out of the flame during the act 
1^ blowiag. This is the only means of maintaining ujiiformity 
t£ temperotture in the whole softened parts of the tnba, without 
which it i& uapossUtle to produce bulb* with sides of equal thick- 

When you dedre to form a bulb at the extremity of a Cil- 
iary tube, that is to say, of a tube that has a bore of veiy small 
diuneter, such as the tubes which ore commonly employed to 
form thermometers, it would be impr(^>er to blow it with Ute 
mouth ; were you to do bo, the T^Kiur which would be introdoc- 
ed, having a great affinity for the glass, would soon obstroct the 
little canal, uid present to the pavage of the air a resistance, 
whidi, with the tuoei of sm^lest interior diameter, would irftenbe 
insurmountable. But, even when the tubes you em^dev have 
jiot so Tery small on internal diameter, you should still take care 
to avoid blowing with the mouth; because the introduction of 
moisture always injures fine instruments, and it is imposuble to 
dry the interior of « capilloiy tube when once it has become wet. 
It is better to make use of a bottle of Indian rubber, which oan 
be fixed on the open end of the tube by means of a cork with » 
hole bored through it. You press the bottle in the hand, taking 
care to hold the tube vertically, with the hot part upaardt ; 3 
you were not to t^e this precaution, the bulb would be turoed 
ou one side, or would exhibit the form oi a pear, because it 
is impossible, in this case, to give to the mass in fusion that ro- 
tstory motion which is necessary, when the tube is held hori- 
zontally, to the production of a globe perfectly spherical in its 
form, and with sides of equal thickness. 

Whenever you blow into a tube you should keep your eye 
fixed on the dilating bnlb, in order to be able to arrest the pas- 
sage of air at the proper moment. If you were not to attend 
to this, yon would run the risk of giving to the bulh too great 
an extension, by which the sides would be rendered so thin that 
it would be liable to be brokffl by the touch of the lightest 
bodies. This is the reason that, when you desire to obtain a laige 
bulb, it is necewary to thicken the extremity of the tube, or to 
combine many small bnlbs in one, that it may possess more so- 
lidity. 

In general, when yen blow a bulb with the mouth, it is better 
to introdnce the air a Uttle at a time, farcing in the small por- 
tioDS very rapidly one after the other, rather than to attempt to 
produce the whole expansion of th« bulb at once; yon. are then 



259 HI 

more CArtain of being able to an«st the blowing at the proper 

When yon, desire to produce a moderate expanmon, either at 
the extremity or in any other part of a tube, you are enabled 
ennly to effect it by the following process, which is fbnnded on 
the property possessed by all bodies, and especially by fluids, of 
expanding when heated ; a property which characterises air in 
a veiy high degree. After having seated one end of the tube, 
and drawn out the other, allow it to become cold, in order that 
it may be quite filled with air; close the end which has berai 
drawn oat, and prevent the air within the tube from commnui- 
cating with that at its exterior; then gradually heat the part 
which you desire to have expanded, by turning it gently in the 
flame of a lamp. In a short tirae the softened matter is acted 
on by the tension of the air which is enclosed and heated in the 
interior of the tube; the glass expands, and produces a bulb or 
■welling more or less extensiye, according as you expose the 
glass to a greater or lesser degree of heat. 

To blow a bulb in the middle of a tube, it ia sufficient to seal 
it at one of its extremities, to heat the part that you wish to in- 
flate, and when it is at a cherry red heat, to blow in the tube, 
which must be held horizontally and turned with both hands, 
of which, for the aalce of greater facility, the left may be held 
above and the right below. 

If the bulb is to be large, the matter must previously be 
thickened or accumulated, or, instead of that, a series of small 
bulbs be first produced, and these Buhaeqnently be blown into a 
little larger bulb, as I have already mentioned. 

Yon make choice of a tube which is not capillary, but of a 
sufficient diameter, very cylindrical, with equal aides, and 
tolerably pubstantial : it may generally be from the twentieth 
to the twelfth of an inch thick in the glass. You soften two 
zones in this tube, more or lesa near to each other, according 
to the bulk yon desire to give to the bulb, and you draw out the 
melted part in points. The talent consists in weU centering — 
that is to say, in drawing out the melted tube in such a man- 
ner that the thin parts or points shall be situated exactly in 
the prolongation of the axis of the little portion of the original 
tube remaming between (hem. This operation ia technically 
termed drawing a cylinder between tico points. You cut these 
points at some distance flvDm the central or thick part, and seal 
one end ; you next completely soften the tittle thick tube and 
expand it into a bulb, by blowing with the precautions which 
have already been described. You must keep the glass in con- 
tinual motion, if you desire to be successful in this experiment. 
Much rapidity of movement, and at the same time hghtness of 
touch, are requisite in the operation 'here described. It is 
termed bkming a bulb bettceen too points. 

To obtain a round bulb, you should hold the tube horizon- 
tally ; to obtain a ^ttened bulh, you should hold it perpendicu- 



QUMa BLOWIMO. 257 

]arlj, with tlie fused extremity turned atwTe ; to oUiin » 
ptar thaped bulb, you Bhould hold the fiised extremity dovn- 
wwds. 

When yoa are working upon a bulb between two itoiiits, or 
in the middle of a tube, you ihould hold the tube horuentally, 
in the w^inBiy manner ; but yon are to pndi the softened por~ 
tioD together, or to draw it out, according as you deeiie to pro- 
duce a lidge or a prolongation. 

Foi some instnunent^ the tubes of wlw^ mnet be small, it 
is neceagaiy to blow the bulba separately, and then to tMer 
them to the requiBite Etdjunota. The Ma»ou of this is, that it 
would be loo dif&cult to produce, from a very snail tube, a 
bulb of sufficient uze and solidity to answer the intended pur- 

The foBowing figure afforda an exoniple of this tort of inak. 
c IS a bulb blown from a 
large tube ; a b, are two 
narrow tubes, soldered to 
the bulb c at two oppoHte 
drtmn out points e and i. See the article " SoUering." I hare 
shown the full size of a bulb of this descaiptiM, at page 227. 

When yon aro at Hb^y to choose the point from which you 
are to blow, you should prefer, let, that where the moisture of 
the breath can be the least prejudidal to the instrument which 
js (o be mada ; 2dly, that which brings the part which is to be 
expanded neareet to your eye ; 3dly, that which presents the 
fewest difficulties u the execatiiw. When bulbs are to be 
formed la complicated apparatus, it is good to reflect a littie en 
the best means of effecting the object. It is easy to an- 
derstEuid that contriTances which may appear very simple i 
per, present difBcultiea in thepra " ' '' ■ ■ > •■ 

1 for conaider^le management. 

8, PlEROINO. 

You first seal the tube at one extremity, and then dire«t the 
point of the &UAe on the part which you desiro to pierce. 
When the tube has acquired a reddiA white heat, you suddenly 
remoTe it from the flame, and forcibly blow into it. Tlie 
softened portion of the tube gives way before the pressuro of the 
air, and bursts into a hole. You expose the tube again to the 
flWe, and border tiie edges of the hole. 

It is scarcely necessary to ohserre, that, if it be a setded ex- 
tremity whidi von dedre to pierce, it is necessary to turn the 
tube between tne fingue while in the fire ; but if, on the con- 
trary, you desire to pierce a hole in tiie side of a tube, you 
should kee^ the glMe In a fixed poutiou, and direct the jet upon 
a single point. 

If the ude of the tube Is thin, you may dispense with Mow- 
ing. The tube is sealed and alWwed to oool ; then, aconiatdy 
closing the open extremity with the finger, or a little wax, yoB 



i,.".oogL' 



25B OLABB BLOWINO. 

expose to the jet the part which yaa derire to h&re pierced. 
Wnen the glaai is Buffidently softened, the sir encloeea in the 
tube being expanded by the heat, and not finding at the eaften- 
•d part a sufficient reeistaiice, bunts through the tube, and thus 
pierces a hole. 

Yon may generally dispense with the sealing of the tahe, by 
closing the ends with wax, or with the fingers. 

There is atill another method of perfbrming this operation, 
which it very expeditions, and constantly sncceeds with objects 
which hare thin sides. Yoa raise to a raliiiih v!hUe heat a uttle 
cylinder of gla», of the diameter of the hole that you desire to 
make, and you instantly apply it to the tube or globe, to which . 
it will atrongly adhere. You allow the whole to cool, and then 
give the auxiliary cylinder a sharp slight knock ; the little 
cylinder drops off, and carries with it a portion of the tube to 
which it had adhered. On presenting the hole to a slight de- 
gree of heat, you remove the sbarpnegs of its edges. 

When yon wish to pierce a tube laterally, for the purpose 
of joining to it another tube, it is always best to pierce it by 
blowing many times, and only a little at a time, and with that 
*iew, to soften the glass but moderately. By this means the 
tube preserves more thickness, and is in a better state to sup- 1 
port the subsequent operation of soldering. 

There are circumstances in which you can pierce tubes by 
fordhly sucking the air out of them ; and this method some* 
times presents advantages that can be turned to good account. 
Finally, the orifices which are produced by cutting off the lateral 
point of a tube drawn out at the side, page 2fi2, may also be 
reckoned as an operation, belonging to this article. 
9. — Bbkdiko. 

If the tube is narrow, and the sides are pretty thick, this 
operation presents no difficulty. You heat the tube, but not 
too much, lest it become deformed ; a reddUh brown heat [a 
sufficient, for at that temperature it gives way to the slightest 
effort you make to bend it. You should, as much as possible, 
avoid making the bend too abrupt. For ^tie puipose, you heat 
a zone of one or two inches in extent at once, by moving the 
tube backwards and forwards in the flame, and yon lake care to 
bend it very gradually. 

But if the tube is large, or its sides are thin, and yon bend it 
without proper precautions, the force you employ entirely de- 
stroys its cylundrical form, and the bent part exhibits nothing but 
a double flattening, — a canal, more or less compressed. To avoid 
this deformity it is necessary, first, to seal the tube at one extre- 
mity, and then, while giving it a certain curvature, to blow cauti- 
juslyl 



isly by the other ex:tremity, which for convenience sake shonld 
preTiouflly be drawn out. When tubes have been deformed by 
bad bending, as above described, you may, by following this 
method, correct the fault ; that is to say, upon si'sling one ex- 



OLAHS BLOWINQ. 2S9 

tremity of the defonned tube, heating the flattened port, and 
blowing: into the Otiier extremity, you can, with care, repnidnce 
the round form. 

That a currature may be well made, it is in general iim iiwiiiiji 
that the Bide of the tube which is to Form the concave part be 
WifBciently softened by heat to aink of itielf equally in every 
part during the operation, while the other side be only softened 
to such a degree as to enable it to give way under the force 
applied to bend it. On this ac«>unt, i^ef having softened in a 
tA^rry red heat one side of the tube, yon should turn the other 
side, which ia to form the exterior of the curvature, towards 
yon, and then, exposing it to the point of the jet, you should 
bend the tube immediately upon its beginning to sink und^ 
the heat. 

Many glass tubes con be conveniently bent after beiiur heat- 
-'- — ■*^-' ■--■■' ' el9). ■" ' ^*--- 



Veiy large and thick 



If the tubes whieh yon propose to solder are of small diame- 
ter, pretty equal in size, ana have thick sides, it is sufGcient, 
before joining them together, to widen them equally at their 
extremities, by agitating a metallic rod within them when soft. 
But if they have tmn aides, or ore of large diameter, the 
bringing of their aides into juxta-position is very difficult, and 
the method of soldering just indicated becomes insofBcient. In 
this case you are obliged to seal, and subsequently to pierce, the 
two ends which you deaire to join. The msposition which this 
operation gives to their aides very much facilitates the soldering. 
Finally, when the tubea are of a very different diameter, yoa 
must draw out the extremity of the la^r, and cut it where the 
part drawn out corresponds in diameter to the tube to which ft 
IS to be joined. 

For lateral solderings you must dispose the tubea in such a 
manner that the sides of the orifices which vou dedre to join to- 
gether coincide witu each other com- 

pletely, as represented in the annraced 

ngure. The upright tube is drawn out 

latterlv, pierced, and bordered, and the 
end of the other tube is bordered to cor- 
respond with it ia size. 

When the holes are well prepared, yoa 
heat at the same time the two puts that 
are to be soldered tc^ther, and join them 
at the moment when they enter into Vi- 
sion. You must pnah them slightly together, and continue t(t 
heat successively idl their points of contact ; whereupon the two 
tubes soon unite perfectly. As it is almost always necessary, when 
you deaire the soldering to be neatly done, or the joint to be 



n 



260 01 

impeioeptiUe, to tenoinate th« operBtion bj blowing, it ia pn- 
per to prepare the extreme ends M the tubes before band. That 
end of the tube b v which you intend to blow Bhould be csrcfuUjr 
fywm out, proTided it be w large as to render dramue out ne- 
oeoBty; ana the other end of the tube, if luge, should be eloaed 
with wax, or if ■mall, should be lealed at the lamp. When ih» 
points of junction ue perfectly softened, and completely ineor- 
ponted with each other, yoa introduce a littie ab into the tube, 
which produces a swdling at the joint. As soon as this boa 
taken place, yon must gcntiy pull tbie two ends of the joined 
tube in difiorent directions, by which means the swelled portiea 
•t tfaa joint is brought down t« the sise of the other part of the 
tabe, 80 that the whole surface becomes continuous. The 
soldering is then finished. 

To solder a bulb or a cylinder between two points, to the 
extremity of a ca^kry tube, you cut and seal one of the punts 
at a short distuice dnxn the bulb, and at the momcmt when this 
extremity is in fusion you pierce it by blowing strongly at die 
other extreniitv. By this means the opening of the reservoir 
is terminated by edges veir much widened, which fecilitates 
considerably its being brought into juxta-poaition with the little 
tube. In order that the ends of the two tubes may be wcU 
inoMporated the ons with the other, yon should keep tlw sol- 
dered joint for some time in the flame, and ought to blowin the 
tube, posh the endf together and draw them aMinder, until 
the protuberance if no longer pereeptible. — See tbe Kticle 



dura ftill Busts an opening too conuderable' to be closed by 
mmply pvahing the two tubes upon one another, you eea clow 
•oca an iqtening by means of a morsel of g^aas, Bf)plied by pre- 
aenting the fused Mid of an auxiliary tube. 

Yon should avoid soldering together two dilFer^t qieciea of 
glass — for example, a tube of hard glass with a tube of flint 
xlaas ; because these two species of ^aas experience a di&erent 
degree of oontraction upon cooling, and, if jomed together while 
in a fused state, are bo Tiolently pulled from one another as they 
beoome cool, that the cohesion of the point of soldering is 
in&Uibly o*eroonie, and the tube breaks. Yon ought also, for 
a similar reason, to take oare not to accumulate a greater mass 
of glass in one place than uiother. 

If the first opention has not been sufficient to complete the 
soldering, the tube mu^ be agaiu presented to the flame, and 
Sgain pushed t<^her at the joint, or drawn asunder, or blown 
into, according as it may ^ipear to be neceasaiy. In all cases 
the soldering m not truly sotid, but inaamuch as the two masses 
of glass are well inoorporat«d together, sod present a sur&ce 
GOntioiious in all pcanta. 

The sioaii blowp4)e, (p^ 238) is that which is to be em- 
ployed in preference to the larger flame, when you deau« ttt 



effect a go»J joining : it ia sufficient to proportion the size of the 
flame to the obiect rou wish to execute. 



flame to the object j'ou wish to execute. 



THE LABORATORY. 

The notion, that a laboratory fitted up with furnaces bbA ex* 

Caive and complicated instrumeatfl, is an absolute requMte 
the proper performance of chemical experiments, ia exceed- 
ingly erroneous. In fact, the truth ia quite opposed to this 
opmion. " For general and ordinary chemical pDrposes," says 
Dr Henry, " and even for ihe prosecution of new and important 
inquiries, very simple means are sufficient: some of the most 
interesting facts of the science may be exhibited and ascertained 
with the aid merely of Florence flasks, of common phials, and 
of wine glasses. In conTertiug these to the purposes of appara- 
tus, a considerable saying of expense will accrue to the ezperi- 
mentaliat; and he will avoid the encnmbrance of various instru- 
ments, the value of which consists in show rather than real 
Utility." It is a curious and instructive fact, that some of the 
moat important discoveries in chemistry were made by persons 
who, either from choice, or motives of economy, used utensils 
of the very simplest character. The laboratory of the great 
Priestley cost a mere trifle; and it ia well known how savingly 
Franklin went to work. The student will beware of procurmg 
Ue large and showy apparatus which strike his eye &om the 
lecturer's table, for they are useless to him. 

Method, order, and cleanliness, are essentially necessary in a 
chemical laboratory. Every vessel and utensil onght to be'well 
cleansed as often as it is used, and put a^in into Its place; 
labels ought to be pnt npon all glasses and boxes containing 
preparations. Apparatus a^d preparations should be kept on 
shelves, or in drawers, where they can be readily found when 
wanted. The care of cleansing and arranging vessels, which 
seems to be t riflin g, is very fatiguing and tedious; but it is also 
veiy important, though frequently little observed. When a 
person is keenly engaged, experiments succeed each other 
quickly; some seem nearly to decide the matter, and others sug- 
gest new ideas; the experimentalist cannot but proceed to them 
immediately, and he is led to pass from one to another ; he 
thinks he shall easily know again the products of the first ex- 
periments, and therefore does not take time to put them in 
order; he prosecutes with eagerness the experimenta which he 
has last thought of; and, in the meantime, the vessels employed, 
the glasses, and bottles, and products, so accumulate, that he 
can no longer distingui^ them; or at least he is unoertun eon- 



263 

eerning tome particnlai' prodset. This evil ia increWKd, if a 
Dew series of operations mcceed, and occupy the laborat<n7, or 
^ he be obliged to qnit it; for in these csmb, eveiy thing goes 
into coniii^ii. Thence it freqnentlv happrais, that the chemist 
loaea the fruits of much labour, ana is obliged to throw awaj 
klmost all the products of his experiments. 

When new leeeorches and inquiries are made, the products of 
all the operations ought to be kept a long time, distinctly 
labdied and registered; for these things, when kept some time, 
frequently present phenomena that were not at all anticipated. 
Many fine aiscorenei in i^eniiBtry Jure been made in this man- 
ner; and many b«vs certainly been loat, bjr Umiwiiig &wsy too 
lustily, or neglecting the products of experiment. 

Yonr work table (oE which man anon) diould be stfong and 
lerd, sod placed fronting awindowinaroom free from dnst and 
disturbance, and where there are no children. Moat chemical 
prepaiatiotiB are poisonoDB or hnitfid; and all should be cars' 
fully kept out of the reach of thoae who might unwittingly do 
themaelTCS harm. 

Beware of the drivings of bottles! Bememher that acida 
and aloalies can either alter the ooloar of clothes and ftimitore 
or bum holes in them. Take care how yon ponr liquors from. 
boUlee, and never let any run down the outside of the botUe: 
I hare told you how to prevent it in the article on decajUatUm. 
Yon should, however, always have aome tow or old rags at hand, 
to wipe up any thing that is niUed accidentally. 

Beware idso of the mischief that may arise from the breaking 
of vewelfl containing large mnttirn of liquid. When distJUadoDB 
are undertaken, or operations of any kind requiring much li- 
quid are carried on, there riiould be no caniets or good fiimilnre 
in the room, or the apparatus should be placed over deep pans, 
as will be described in a subaequrait artide npon Distillation. 

The sort of experiments most proper for Me parlour Mile are 
those made with the blowpipe, or with the small veasels which 
are adapted to the lamp fimiace. Experimenting in miniature 
can be carried on to a great extent. There is scarcely an oper- 
aUon described in the preceding pages capable of producing re- 
Bolts unattainable by an appwatus of blowpipes and test tubes 
wrought with esse and s^ty over a tea tray or a large earth- 
enware dish. 1 would there&re recommend the young student 
' ' ' 'meuts Ml the smallest scale. It is what the 



most eminent <meiniata are doing more and more every day. The 
elevereet philosoidier is he who can effect a given object by the 
easiest means. 

1 rectHmncnd the young student to buy only the most indis- 
pensable articles at first, and to increase his stock of apparatus 
by buying other articles when he wants them. Most people 
fall into the error of buying a great quantity of apparatus Tor 
which they have no use, particularly when they b^in with the 
purchase of apperatus only intended for the lecture table. 



TDK UlBOSAtOtlT. 263 

The two most esaential tequLgites to be pcovided in the con- 
version of a parlour or a tthool room into a labaralimf, are Vbm- 
iiLiTiOH and a proper Woiia Tablk, on both of which Bul^eots I 
shall say a few words. 

Vknttlatior. — It is extremely COTivenient to have the powe» 
of perfomuiu; in a comfortable room a variety of chemical 
operatioi^ which are necanarily attended by the prodnction erf 
mneke and miffocating vaponJH, withoat being at the aama time 
annoyed by those vapours. To gmn this object, Behzelidb re- 
eominends the use of a moreabla chimney, or ventilator, of the 
following constroetion. An opening is broken into a chimney, 
and a black iron pipe, sis inches in diameter, is fixed into th« 
hole so produced. The length of this pipe may be 18 or 24 
inches. Across the middle erf it, there muat be a damper, fixed 
in a Icmg flat box, in such a manner that the pipe may either 
ite left viide open, or be more or less cloeed, as occasion requires. 
Where a hole cannot be broken into a chimney, the pipe may bo 
passed through a wall, or through a window, uid be connected 
outside -with a few feet of perp*ndiculaj' pipe, to create a 
draught ; or it may ^ s^aight upwards through the iW of th« 
wartinent, if local drcnmetiuicM reader that method preferable. 
The iron pipe, fixed in nay of these ways, forma the nppei 
portion and support of the ventilalor, which is represented in 
the annexed fignre. 6«n, 
is the end of the iron pipe 
that goes into the chimney. 
e d, is the damper and its 
box. # m if, ia a tube 
of paper (or pasteboard) 
strengthened by two sticks, 
m I, and of, to which it is 
nailed. / / ff », is a eir- 
cnlar paper funnel, con- 
nected with the paper pipe, 
and strengthened like it by 
' tw» sticks, / A, and t g. 
This fiiBttet shonid be nearly three fe«t wide at the bottom, 
and about eight inches deep from the end of the paper pipe. 
gkih, is a circular hood, or canopy, of wax cloth, (water- 
proof doth weiild answer better, but painted canvass would be 
cheapest,) measuring five or six feet in diameteT at the lower 
end, where it is stretched by a strong iron wire, and sewed above 
to the paper ftmnel at A 9. The whole apparatus is fastened to 
the iron tube, fr a n, by a flexible connector of wax doth, 
(wsterproof cloth,) a n m e, which is fastened at one end to 
the irMi pipe, and at the other to the pi^r pipe. A ring ia 
fastened at the top of the funnel /, from which a cord passes 
upwards, over a pulley fixed to the roof, and is connected with 
a leaden counterpoise and hand pull, in a comer of the room. 




264 TBX LABOBATORT. 

.'By this means the canopy, irhea not in use, can be pulled up 
out of the waj. 

Under a ventilator of this description, you place a work table 
with its lamp, and perform the various operations which pro- 
' w steam, smoke, or deleterious gases, such as evaporation. 



boiling, solation in acids, glass blowing, testing with Bulphui 
etted hydrogen, &c. Independent of the comfort which such 
a ventilator gives, it is of importance, as tending- to prevent the 
unhealthy effects produced on the body when such vapours as 
I have alluded to are permitted to remain in a room and to be 
inhaled. It is in all cases advisable to give an apparatus of this 
kind a coatt^siUceons varnish, to prevent itscatcning fire &om 
^arks and burning with flame. Siliceous varnish, adapted for 
tliis pnipoae, is not an expensive article. 

Wore Table, — Although any sort of table can be used to 
make experiments upon, it may not be amiss to state what sort 
of table answers best Ab the breaking of glass vessels and 
other accidents cause the spilling of chemical solutions which 
corrode wood, and destroy colours and varnishes, the table of 
the chemists commonly has a very dirty appearance. 'Diis, 
however, should be prevented as much as possible. It is un- 
pleasant to Bee, and its toleration encourages a habit of inattention 
to dirt which is injurious to successfiil . experimenting No 
teacher should suffer anything dirty to be used or to be seen in 
use by his pupils. Dr Wolloston was particularly nice in his at- 
tention to the state of his apparatus ; Mitscherhch works upon 
taUes of polished wood, having snnk trays of glazed porcelam ; 
and Berzelius instructs us to inlay our table with slabs of pot- 
tery (glazed Batch tiles, which however are not to be procured 
in Scotland.) He says that the tiles should be laid close to- 
gether and cemented with lintseed oil varnish mixed with oxide 
of zinc or with sulphate of barytes. 

I have been trving to manu&ctnre glazed stoneware trays 
or work tables for chemists, but have been hitherto disap- 
pointed, in consequence of the dif&culty experienced in firing 
large plates of stoneware, without injury to their flat farm. 
I shall probably, however, yet succeed m making some use- 
ful article of that description, as my experiments are stUl 
going forwards. In the meantune I may mention that a table 
with a cast iron, or lead top, answers veiy well for most pur- 
poses. Such a table, placed under a ventilator in this manner, 
at once converts a common dwelling room into a convenient 
chemical laboratory. When, however, you are obliged to work 
at a good table, it is prudent to employ an old tea tray, a large 
flat tray of sheet leai^ a stone pan, or the sm^ flat glazed stone 
trays described in the Appendix- These may save the maho- 
gany from destruction. 

. Besides the work table and a contrivance for carrying off un- 



Ld 



THB U.B0KATOXT. 265 

ileaasnt T^mns, time areafewother requigitMneeeBUiytobe 
lad in nwrjr laboratory, howerer small it may bo, uid on which, 
for that reason, I ibeil say a few words. 

An abundant Bnpplv of water is aeceeearj, and it is very de- 
arable that a unit and cistern should he at hand; but if these 
cannot be provided, a stone greybeard, holding at least a gaUon, 
with a stop cock fixed into the side of it near the bottom, 
should be fixed up breast high for the supply of water, and be- 
low it there should be a large pan or another greybeard, with a 
Isige fiuinel, for the reception of dirty water. 

There should be a supply of draieert and thelvet, of various 
aize8,toholdbottle8,jarB,flaska, work tools, and all sorts of ap- 
paratus, in good order, ready for use. If the room devoted to be 
used as a laboratory, contains cupboardi, they may be fitted up 
for the reception of apparatus; if not, the work table may be 
divided into two parts, and the one half be fitted np with 
drawers, and the other be formed into a cupbirard. Or,finaUy, 
both drawers and shelves may be affixed to the wall, care being 
taken, where this is done in a dwelling house, to lock up, or to 
place all injurious or fragile things beyond the reach of children. 

A candle or small oil tamp, and a supply of lucifer matches, 
or a hydrogen lamp, for providing a Ught; and a note book, 
with pen and ink, for journalising the experiments which are 
performed, are also indispensable. 

Ah to tbeapparatus necessary to be provided, the quantity and 
▼arietr must depend upon the course of operations which is to 
be undertaken, and upon the means or liberality of the operator. 
In the lists of ^paratus and preparatbns given in the Appen- 
dix, I notice what wilt be required in a place where experimenta 
in various branches of chemistiy ore to be'carricd on. It must 
necessarily be left t« the taste and judgment of eveiy reader to 
procure what appeais to bo most adapted to his particular wants 
or intentions. 1 have endeavoured to assist bim in selecting the 
differuit articles oi apparatus, by giving him alt the information 
in my power respectmg their mlue,hoOi philoMphioal and peeu- 

I proceed now to describe a few general operations, chiefly 
relative to the preparation, alteration, and repair of apparatus, 
which may not unfitly close this article. 

Cork Boriho and Cuttino. — As corks of various siEeB are fre- 
quently in demand, you should be provided with two or tlire« 
large pieces (half a square foot) of cork of the best quality, 
(soft, tree from holes and from hard lumps,) and of different 
thicknesses, from which to cut what you nay require. The 
tools which you will need for shying corks for various pur- 
posee ore as follows: a knitting needle, a small round file, a 
tai^ round file, a flat file, a presB, a set of cork borers, and • 

Kn^t. — A common ahoemake/s knife, with a suidstone fia 



266 THB LABOSlTOBr. 

■hArpentiig it npon. With this j<m cut th« pwM of eoA as 
nearly into the eliap« von wiah it a* yon can. 

Flat File.—V/iih tins yon file the oork into the deeired shape. 
The teeth of the file must not be 

too fine, bnt rather of the ib«> ,_- ^ ^.m. . BMEMa ijr-'^ 
order. It is eaaier to file a cork ™-^* " — 

tlian to CQt it into a given shape. 

Cork Prei*. — Two short strong pieces of hard wood, connect- 
ed by a hinga at me end, aomething like a pair of nut eradcsn, 
with a series of corre^ionding semi-cinnilar grooTea, of differmt 
sizes, in the feces that meet together, like the cavity a, pafe 40. 
The uae of this press is to sqaeaxe a Fonnd ooi^ till it is softcoied 
and made elastic. 

Knitting aeedU. — When yon want to make a small hole 
through a cork, you heat the knitting needle red hot, and pnah 
it into the cork. When the bole is burnt half way through, 
yon puU out the needle and push it into the opposite ride of Uie 
cork. lu performing this operation, you hold the cork between 
the finger and thumb of the lei% hand, and take special care to 
bum the hole as centrical as possible, and to hold the wire so 
steadily as not to make the hole irregular or fnnnel shaped. 

Bound File*. — When a hole is once burnt through a cork, 
it can be enlarged to any extent by means of round files, with 
^ ^ _-— ■ I rough teeth (fine rasps), of which it 
is necessary to have a small one 
(thi«eiBefa),aDdalai^ane(aixinch). Itrequireeoonsiderablt 
care and practice to file a hole cylindrical from end to end. 
You succeed best by holding the cork betwetoi the left finger 
and thumb, and turning it gradually round about, while the 
file is managed by the right hand, and applied at the two mds 
of the cork alternately. When the t^^ of the file beccone 
tilled up with cork and dust, they can be cleared by soaking the 
file in a ley of lime and potash. 

Danqers Cobk Bobeb. — The cut represents a front and dde 
view of on instnunent for boring or cutting holes in cwks. 




devised by M. Dahoeb, of Paris. It consists of a hardened steel 
tube, one end ctf which is fixed in a handle, and the other end 
ground to a cuttins edge. The cork to be bored is held in the 
teft hand, and ^e Dwer, previously oiled, ia held in the right 



267 

hand, and preved throngh tbe cork with a twintiDg motion, 
after the roanner of a gimlet or cork screw, by which means a. 
' cylindrioKt piece ia neatly cnt out of the cork, and a amooth 
cylindrical hole produced. There is an opening on the aide of 
toe borer made to permit of the extraction of the cylindera of 
cork from it. Ae each borer only cute one size of hole, it is 
neceaaary to be provided with several siaea, to make perfora- 
tiona for tnbea of different diametera. The price of steel borers 
of this description, with wooden handles, in aiEea from ^ inch to 
i inch diameter, ia la. 3d. each. 

MoHK'a Cork Bokbr. — An iaatrament for boring corica which 
answers better than Danger's, has been recently (AnnaltH tier 
Pharmacia, Januar J837,) deacribed by Dr Mobb of Coblentz. 
' It is a tube of tin plate, six inches long, bent as cylindrical 
as poaaible, and soldered flat where tbe edges meet at the side. 
There should be a set of 12 tubea, passing within one another, 
like the drawers of a telescope, tne lai^eit of them being ^ 
indi wide. A wire ring is solaered round one end of each tube, 
and the other end ia sharpened to a cutting edge by a half 
ronnd file, the flat aide of which acta upon the outside of the 
tube, and the round part npon the inside. The 12 tubes ax* 
marked by the file on their rings, and a set of holes are cut in 
the aide of a tin plate to serve as a guage for the width of the 
tin tubes, each nole being numbered to correspond with the 
tube that fits it. The ose of the gn^e is to determine the 
thickneea of the glass tnbes for which holes are to be bored, and 
to show which cutting tube should be used for the purpose. 
As the tin tubes are of like thickness throughout, the piece of 
the cork which ia cut out to farm the hole, passes easily up 
the cutting tube in the form of a solid cork cylinder, fit for a 
Btopper. 

The operation of boring is very easy. The borer ia hold in 
the right hand, and the cork is applied with the left hand to 
the sharp edge of the borer, where tt is held steady, while the 
borer is slowly turned round, or else the cork and borer are 
turned round in opposite directions. Very little pressure is 
used, the cutting being performed by an operation similar to 
that of sawmg. The forefinger of the left hand is applied to 
that part of the cork where the borer is to como out, and when 
the approach of tbe borer is felt, the finger is remored, another 
cork la applied in its place, and the tuniing of the borer is re- 
Dewed with a slight pressure. By this means the cork is cut 
oat with a neat round end. The orifice made by thia opera- 
tion is perfectly cylindrical and smooth on the sur&ce. It is 
necessary, for each operation, to moisten the cutting tube both 
inside and outside with a little sweet oil. Each borer may be 
proTided with a hollow wooden handle, which makes the nse 
of it more conTenient. 



I,, Google 



266 THK LABOKATOKT. 

Ai I liave not been able to get tin plate tabes made of very 
■nail diametera, nor made of any mxe withoat an overlap of 
the metal at the line of junction, which o&en an impedimoit 
to the boring, 1 have been using thin brtut tube* for cork boring, 
with great advant^. These are easily procured, and in miSi 
Tariety, that from the diameter of \ inch np to that of 1^ inch, 
I have obtained more than twenty varieties, with any of which 
smooth cylindrical holes can be cnt in cork, by the extraction 
of smooth cylindrical pieces of cork, which anawer for stoppers. 
The brass tnbea are sharpened at one end, internally by a snail 
ronnd file, and externally by a flat file, in the maimer describ- 
ed above, and they are oued prerioua to use. After every 
operation, the cork cylinder most be pushed out of the borer, 
by means of a thick iron wire. All often as the borer gets dnll 
on the edge, it must be sharpened anew by the files. If the 
borer happens to get squeezed and lose its CTlindrjcal form, it 
must be hammered into shape on the spike of an anvil (p. 273). 

Hitherto 1 have only succeeded in procuring tnbes of four 
inches in length, which is too short for convenient holding, ex- 
cepting for the tubes of le«8 than half an inch in diameter. 
These, however, are the most useful kinds, since it is easier ta 
enlarge a hole by the file when once it is made, than it is to 
make it in the nret instance. And for making small holes, the 
narrow cork borers are incomparably better than the red hot 
knitting needle. The price of these small aixed brass borras is 
very low, a set of 6 tubes costing only Is. I expect soon to 
succeed in procnring the larger sizes, 6 inches in length, and 
perhaps assorted to tne width of 2 inches, with a tube of wbicb 
diamet«r I find it possible to cut cylindrical corks for closing 
laive tubes, such as the condenser, page 201. 

It is not necessary to procure all tne various mzes of small 
boring tubes, which I have sud it is pottible to procure; be- 
cause I find, that with even that great assortment, it is im- 
possible to dispense with either the flat file or the round cote, 
BO variable are the sizes of glass lubes and (f flask mouths. It 
is however useful to have a pretty good assortment of borere, 



:, and another that can m^e a hole to fit the tube. 
When this can be done so as to dispense with the files, it tave* 
a great deal o/ time; and as the cost of the borers is so trifling, 
tlus is a consideration of importance. 

1 have also endeavoured, though yet without success, to pro- 
cure cork borers of the necessary variety of diameiers, in the 
form of thin tteel cgHnders, which would be more usefol and 
durable than either tin plate or brass. 

Since the fbr^;oing article was written, 1 have received from 
the manufacturer a set of taehe bratt ecrk ftorer*, H* inehet »n 
length, perfectly smooth in the bore, and of the following dia- 



meton: 2, 3, 4, ffl, 6, 7, 8, 10, 12, 14, 16, wid 20 a 

an inch. With Uiis set of borets, and a round aod flat £la i_ 
sharpen them, and a mnaU and large Tonnd file for occasional 
alight enlargement of the holea which they cut, it is poasiUe to 
prepare in a few minutes cork cyliuden, or cylindrical holtss, 
«f any rise between ^ioch and l^inch; so that the operation of 
ad^tioK tubes to flaski, which was formerly so troublesome 
and so destractire of time, is now rendered so very facile and 
certain as to do away with the necessity of (^plying cements to 
corks in at least five cases oat of aix. 

The juice of this set of twelve brass cork boren, is 3b. — ' 



EliUTIc Tubs Mikinq. — I have referred, at page 225, to the 
use of elastic tubes of caoutchouc in connecting together the 
•ereral parts of a complex, glass apparatus. A great many case* 
of this sort will have to be teferred to in the subsequent pages 
of this work, and as these tubes have frequently to be made afl 
well as used by the experimenter, it is proper to describe the 
method of malung them. The material of which thev am nude 
is sheet Indian rubber of about the twellUt of an inch in thiok- 
Qesa, which may be bought in Ols 
inches tor 6d., and of 100 square ii 

Take a piece of the sheet rubber, 1 or 1^ inches long, and a 
little more than three times as wide as you intend the tube to 
be. Take a glass rod rather smallei than the intended caout- 
chono tube, fold a slip of paper ronnd the glass rod, and over it 
the piece of caout^ouc, previously saftened by wanning before 
the fire. Fold the two ^ges together, and cut off the double 
projecting edees by a pair of aciaaorB, so as to produce two 
parallel atrai^t e^ea. Put the two dean sorfoces thus pro- 
dnced face to fiice, being careful not to let the fingers or any 
thing else touch them. Preu the two faces together by the 
thumb nails, and finally press the seam &om end to end with 
the flat part of the thumb nail. The junction is then effected 
and the tube complete. But if the fingers or any dirt is allowed 
to touch the clean cut surfacea of the rubber, they cannot be 
made to unite by preoBure. After you have withdrawn the 
gla» rod and the slip of m>er from the rubber tube, you are to 
smear ita inner sur&oe with flour or fine ashes, to prevent the 
BubaeqneQt sticking togetlier of its aides, which is oUieiwise 
liable to take place. 

To ibrm a conical elastic tube for connecting glan necks of 
unequal uz^ you must fold the rubber upon a retort neck, or a 
conical piece of wood, such as the stick used in putting wicks 
into lamps. A piece of p^er previously adjusted to the cone, 
and cut to th« proper length, serves as a pattern by which t« 
cut oat the necessary slip of rubber from the ahaet without waste. 

A oaontchoue tube answers best wheat ita two ends are at near 



«glc 



w pomble gf tlw «une nxe u the two glaas tnbea wUdi it b to 
connect. It is pat orer them with b little atretehing, and binds 
t^m mffidmtly tight for maay purposes withont tying. But 
when tying isnsceesary, it is b^ done with silk oord, which is 
less tipt than cMnmon twine to cut through the eaoutchoae tabe. 
The connected glue tubes need nfirer be more than a quarter 
of an inch asonoer, so that very short caoutcboac tubes ore safB- 
cient for the purpose. 

These tnbce are destroyed by a heat exceeding 170° F., and 
eonseqoently cannot suffer the passage of steam. They are acted 
npon Dy fat and bv Tolatile oQs, tontentine, &c.; and also by 
strong nitric and Bolphuric acid, and afightly by chl<»ine. Thejr 
permit the passage of all other gases. 

PaSFARATIOK OF SHEET Hdbber fkou Shall Bottlib. WheTtt 

small bottles of Indian rubber are more easily proctmd than 
sheet rubber, it may be nsefiil to know how tbey can be expand- 
ed to as to answer the same purpose. Place a sonnd rubber 
bottle at the bottom of a beaker glass that nearly fits it. Pour 
into the glare as much sulphuric ether as rises to the neck of the 
bottle but does not carer the neck. The ether must be ^uite 
free from alcohol. Bind the mouth of the glan aix tight with a 
piece of wet bladder, and set it in a cool place for 6 hours, if 
the bottle is small and thin, or for 12 or 24 hours according to 
the greater size of the botUe. The steeping should continne 
till uie rubber ceoses to be elastic, but not till it becomes so soft 
as to stick strongly to the fingers. When the bottle is sufGcient- 
^r soaked, put a little powdered starch into it, and shake it about. 
Then ins^ the neck of a stop cock into its mouth, using a cork 
when the month of the bottle is too 1 ' "' '< < 

Fold a bit of leather twice round the ni 
stopcock, and tie it on with a string. When the rubber bottle is 
thus fixed ui tight upon the stop oock, you open the latter and 
blow a little air into the bottle, then you close the slop cock and 
let it rest a while, after which you open it again and blow in a 
little more air. And thus you continue to blow eii into it, a lit- 
ided, which it is 
it one twentieth 



Guss CirmHO ind Orindino. — It is frequently necessary, in 
the laboratory, to resort to glass grinding, partlcnWly when yon 
reside at any distance from professional glass cutters and instru- 
ment makers. The use of glaas grinding is to fit stoppers to bot- 
tles, to adjust flat glass plates to the mouths of tunnels or jars, 
and to ad^t retorts to receivers, and tubes to gas bottles, in such 
a manner as to dispense with cementing, 

Ui^roohd stoppers can scarcely be fitted to nnground bottles, 
without the use <tf a turning lathe. A copper cone is fixed in 
the lathe, and anointed witlk a mixture of emwy and oil, and 
the bottlo, held in the right hand, is forced nprni the rerolTing 



THB LABORAToar. 371 

copper cone. For cutting the stopper, a rerolTiijg hollow cop- 
per cone is employed in the some manner. The copper tools 
mnBt be only very Bligbtly conical. When the stopper is tbiM 
made to correspond in a rather niu^h way to the bottle, it la for 
the purposes of eak commonly considered to be finished, bnt for 
tue in ^emical operations the adjustment reqnirea to be made 
more perfect. This is managed by holding the bottle and Bto|h> 
per in your two hands, anointing the latter with emery and oil, 
and working the two together till they fit properly, that is to 
say, till they turn round easily, and are easy to put cloee bother 
and to separate. It is necessary to have emery of three different 
degrees of fiuenees, and to proceed gradually from the coarse 
to the fine, taking care to wash off the paste of coarse emery 
from the vesela before von apply the finer sort. 

Glass stoppers sometunes stick so tight into their bottles, that 
they cannot be pulled out in the ordinary way. The beet way 
of removing them is to bold the neck of the bottle horizontally 
over the ffaine of a amall spirit lamp, taking care to turn round 
the bottle continually, by which means the whole neck of th« 
bottle — the cylinder which embraces the fixed stopper, is sud- 
denly bested and expanded. The stopper then commonly 
Jooeens and may be pulled out. But when it happens to m 
cemented in its place by saline matter, it is necessary to invert 
the flask in a cup of wat«T, and allow the salt to dissolve. 
Sometimes, a drop of sweet oil put ronnd the stopper, and al- 
lowed to rest there a few hours, while the bottle is placed in a 
warm situation, will soak in between the neck and stopper, and 
cause the latter to loosen. Frequently, a piece of tiiin cord, tied 
round the stopper, affords a handle by which the stepper can 
be extracted by a steady pull. And in other cases, a few sUght 
blows with a Mock of wood (never with metal), applied to each 
side of the stopper, will loosen it. When, however, canstio 
alcaJi has got between the ground faces of a neck and stopper, 
and the latter is fixed, thue is no hope to be entertuned of ita 
extraction. The cutting off of the neck of the bottle is then tha 
only remedy. 

For giindmg flat plates of gUas and the e^^ of vesseki, it it 
necessary to be provided with three discs of sheet lead, <» 
copper, eight or ten inches in diameter, upon which the glasR ii 
ground with a mixture of emery and water. Each plate ts em- 
ployed with emery of a different degree of fineness ; the saoia 
powder is always used with the same plate; and the glaas ia 
careiully washed from one before it is applied to the other. If 
this is not attended to, the work becomea full of scratches and 

Lapidary Work. — The cnttii^ of stone is effected in the sama 
manner as the cutting of glass. It comes to be neeeseaiy in 
some caaea of dirtillation where the stoppers of flasks, whkb 
require to bo provided with gas delivenng tubes and founela, 
oaanot be made of cork. The sabstancea used in sncit oases art 



TBK LABORATOKT. 



CTOcdblN. Hu7 of these mbiUiicM ram, howerer, be winced 
bj meaiu of & knife and file into the deaicd forma. 

A more importaDt, and a ttricter example of lapidaif woric 
i* afforded in the onttinr and polishing of minerala, many of 
which can onlj be {iniperly examined as to their an{»rent eaa- 
■trnctian and itate of mechanica] intermixture, after being cut and 
polished. The mineral U for this purpose broken to an eran 
mrfiMe, and is ground upon lead plates, with water and emery, 
of which at least Ave different sorts, in reaped of fineness, must 
be provided. In ereiy case of passing mm a coarse emei^ to 
a finer sort, the mineral most be carefully washed from — >--<-- 



of powder, which otherwise would produce scratches. Finally, 
the mineral is noond with rery fine emery prepared hy waeh- 
ing, (pages 6, 6), and is polished upon a lead plate with btqrali 
or niuhed red oxide of ircm, (jeweller's ronge). This <^er- 

joa reqaires more patieoiee than skill, and ttie art is readily 

aqmni. 



re prepared b_ 

pOuading and sifting; the finer b^ mixing the powderM emeiy 
in water, and ponring off the liqmd after j miuuto's snbsde"" - 
and again after 2 minutes' subsidence, and so on ; by which m 
a variety of different sediments are obtained. 

The Lapidary's wheel is a diss of copper or lead which is made 
to Terolre horizontally. The object to be cut is held steadily 
npon it. Slices of a mineral are cut by a rerolving tiiia disc of 
copper, having a rough edge anointed with a paste of emery, or 
^ diamond powder. The mineral to be sliced ii preosed steadily 
•gainst the e^ of this revolving disc 

WoaxtNO or HKrue. — There are sevarsl snail tools of ao much 
nse in the repair or alteration of the metsllio parts of chemieal 
KiparatuB, that I may as well give them a short notice among 
the other odd matters which make np Ibia article. Schoolroas* 
tors and parsons residing in the country, whra^ instrnment 
makers do not abound, cannot dispense with the use of theae 
tools, nnlen they propose to give up the pujsnit of the iue^ce, 
or to carry on theiT ivMorchea and dcmonstratiosi nmler 
needless difficulties. 

Strong Sheart. Useful in cutting sheet metals into di^M. 

A Smaii Vice, which can be screwed to the edge t£ a table 
whcu it is to be used. It aerrea to hold wires and othra aab- 
■tancea, when being filed or otherwise wrought. 

A Band Viee, which is a vice fastened to an iron rod, to be 
held in the hand when used, serres to secure small articles while 
they undeigo filing and other operations. It serves eapedally to 
hold the three edged needle or drill, with whichjt is sometimes 
r to enlfoge the orifice of the blowpipe nozcle. See 



necessaiT i 
psm 117. 
PU 



'liert with rough tsctt. This instnuneait serves to bold short 



THB LAfiOEATOBT. 373 

lengths of wire which have to be twisted, or suhstaDoes irikich 
ore to be filed, &c. 

A Small AtMI, which can be screwed when in use to the edge 
of a table. This inBtnuneiit has a square flat lop, a ilat wedg* 
at one end, and a spike or round conical point at the other end. 
The wedge has a hole pierced through it. Upon the square part 
jou flatten subEtances. The hole is used to turn the end of a 
wire at right angles. The round spike is used to curl wires into 
lingH, to beat plates into cylinders, or to correct any twist in ft 
cylmder. It is therefore useful in putting the brass cork boren 
into shape, when they happen to get squeezed flat fpage 268). 
' The wedge is used in bending wires or plates of metu at various 
acute or obtuse ausles. 

The operator w^ bear in mmd, that metalB can be bent and 
hammered into form most readily, when they have been an- 
nealed by being heated to redness and allowed to cool slowly. 

File». A flat file, 6 inch, with fine teeth, Another, 9 inch, 
with coarse teeth. A round rat's tail tile, 6 inch : another, 9 inch, 
the same sort as used for borii^ corks. A h^ round file, 6 or 8 
inch, the some as used for filing the cork borers (page 291). A 
triangular file, 3 inch, the same as used for cutting glass tubes 
(page 248). 

A gain with fine leelh, fixed in a bow handle, nsed for cutting 
off lengths of wire, pieces of tube, comers of apparatus, &c. 

A small quantity of tiTitmith's totder, and a little powdered 
rosin, should also be provided, by the help of which and the 
blowpipe, pieces of tin plate can be readily joined together. 

A Drill and Drill Bow. This serves to bore holes in plates 
of metal, or in the ends or through the sides of metallic wires. 
It also serves to bore holes in gla^ as mentioned at pi^ 2S0. 

A Screm Plate. Adapted to cut projectinE screws upon the 
ends of small wires. It must be accompanied by a set of small 
steel screws qualified to cut hollow screws to correspond with 
the projecting screws which are formed by the plate. 

It may here be mentioned, that all instruments which are 
intended to abrade metal, as drills, files, saws, &c., must b« 
moistened with svseet oil, wliile all instruments which are in- 
t«nded to abrade glass, must be moistened with thick M nf 
tm-pentiTte having eam^tor dissolved in it. 

CEtTENTTNo. — 1. WKcu vapouTS of WBt«ry liquors, and such 
others as are not corrosive, are to be confined, it is suflicient to 
surround the joining of the receiver to the retort with slips of 
wet bladder, or of linen, or paper, covered with flour paste, or 
mndlage of gum-arabic. 

2. Soft cement is made of yellow wax melted with half Us 
weight of turpentine and a little Venetian red to give it colour. 
It can be easily moulded by the fingers, and sticks well to dry 
substances. 

3. For containing the vapours of acid, or highly oonwin 

,oo;,lc 



274 

■abrtanc«s,/(it luts ia mode uae of. This is fonneS by be^in^ 
perfectly dry and finely sifted tobacco pipe clay, with punteis' 
drying oil, in a mortar, to lach a consistence that h may be 
moulded hy tke hand. To use it, it ia rolled into cylindera of 
a oonvenieDt size, which are applied, by flstteniug them, to 
tha joinings of the reneli, which mnat be qnite 6xy, as the 
least moisture pierenta the lute from adhering. Tiie late, 
when applied, is to be eorered with slips of linen spread with 
the lime lDt« ; which slipa are to be fastened with pack thread. 

4. When penetrating and dissolving raponrs are to be coB' 
fined, the lute to be employed is of qnick lune slacked in the 
air, and beaten into a liqoid paste with white of eggs. This 
lavat be applied on strips of linen; it is very convenient, as it. 
easily dries, and becomes firm. This lute is very useful for 
joinrng broken china waic. 

6. For eemeutjng stoneware to metals and wood, litha^e 
and red lead mixed and worked up with spirit of turpentine, 
make* a good cement. It takes sereral days to give off the 
torpentone and become dry and hard. 

e. Cement for fostoning brass necks upon ghiss jars, &c. : — 
4 parts of rosin, 1 of wax, and 1 of miely powdered brick, 
mdted and well mixed together. It is to be put on warm, bnt 
care is to be taken not to apply it so hot as to split the glass. 
It holds very hard. 

7. Mix Imtaeed meal with water, and knead it into a stiff 
pasto. It soon hardens and withstands the fumes of acida and 

. ammonia. It is better if made with lime water, or thin glue. 
It is charred by a strong heat. 

5. Thick ^m water, with pipe clay and iron filings. Mix: 
welL It becomes verv hard and finn, and is fit to be used 
where it is required to hold good a considerable time. 

9. Plaster of Paris, stirred np with Tnillr, starch water, or 
thin glue. It bardens immediately, and is very 

tgood for securing tubes in flasks, when the cotka 
do not fit well, and gases are to be prepared in them. 
The cut represents a case where several ^aas tubes 
ore passed turough a perforated stopper of semen tine, 
/_. o'ra\ _i . ; 1 • 1, ti.j j ti 



(page 272), where a paper jacket is tied round the 
neck of the fiask with string, and the cnp so made ia 
fiUed up with tbin plaster of Paris, whicn applied in 



this manner, makes a very effective cement. 

10. Dissolve melted India rubber in boiling lintseed oil, and 
afterwards thicken the tatter with pipe clay till it forms a stiff 
mass. The thorough incorporation of the pipe clay demands a 
great deal of labour. This is a capital cement to be used when 
adds are to be prepared. 

11. Oemmt Jor fattening labeU upon bottle*. — Soften and 
sabseqnently boil glue in strong vinegar. During the boilinc, 
thicken it with flour. Tliis mixture can be preserved in a soft 
state witboat bectxning mouldy. It should be put into a gla«a 



THs i^BOBATOsr. 275 

bottle^ with a wide neck and a ground stopper. Wh^ it is to 
be used, it is taken out of the bottle on the point of a spatula, 
warmed over the lamp, if too thick ibr nae, and then ntread 
upon the paper. It holda well. — To tliis method of affixing 
names to bottles, I ma;^ add an account of a Bed Ink for virit- 
ing upon glau. — This is made from cinnabar, amber varnish, 
aad oil of turpentine. It readily dries, is not washed off by 
water, but can be disBolved by spirit. The use of it, is to write 
upon glass veeBels the name of what they contun. Bottles for 
re-agenta, prepared with a white enamel name plate, can be 
marked with this ink. 

12. f7nitw»o/ Cement. — Curdle skim milk, press ont the 
whey, break the curd in small pieces, dry it, and grind it in a 
coffee mill. Take ten ounces of dry curd, one ounce of fresh 
burnt quicklime, and two scruples of camphor. Mix the whole 
intimately, and preserve it in small wide mouthed bottles, closely 
corked. When it is to be used, mix it with a little water, and 
apply it immediately. 

13. Diaraond Gemeat for Blaii or Porcelain. — Dissolve five 
or six pieces of gum maatic, as large as pcaa, in the smallest 
possible quantity of alcohol. Mix this liquid with two ounces 
of a strong solution of isinglass, (made by softening and dis- 
solving isinglass in boiling brandy or rum to saturation), having 
previously incorporated the two ounces of isinglass solution with 
two or three small pieces of galbunum or guu ammoniac, by 
trituration. The mixture is to be preserved in a well closed 
bottle, and is to be gently heated by holding the bottle in hot 
water at the moment when yott are going to use it. 

The employment of thoroughly good corks often supersedes 
the use of cements. It is easier to procure a good cork than to 
make a bad cork fit air tight by cementing. 

Cleansiho. — When an experiment is ended, the vessels em- 
ployed in it should be thoroughly cleansed and put away. Wash 
your glasses in a tub. If tiie dirt adheres, soak them well. 
Do not rub them with sand to get them clean. Use tow and 
rough ended copper wires to cleanse the inside of glass tubes. 
Clean very small tubes by means of a slip of whalebone, with a 
fi>ld of blotting paper about it. A stick and towel can be used 
in cleansing the inside of laige glasses. An old mlk handkerchief 
isverygood to clean small glasses with. Oil flasks can be cleaned 
by a little oil of vitriol. Rosins and turpentine can be cleaned 
out by alcaline solutions. Tbe insides of glass flasks can fre- 
quently be cleaned by shaking pieces of raw potatoe in them 
with water. Black ashes are of use in other cases, and where 
mechanical action is indispensable, pyrope or Bohemian garnets, 
is the best thing to use, being nearly as cheap as leaden shot, 
and not liable to communicate any impurity. The sooner you 
cleanse vesseb after they are done with, the earner the dirt oomes 



276 TBK LABOKATORT. 

«ff. It ia a Tery troublesome and expenuTe practice to allow 
dirty glasses t« BccuTnulate. 

Tne young experimeDtei may excuse a few words respectiuK the 
cleansing of his nands from certain symptomB of industry nhicli 
he may possibly not be de^rous of exhibiting before thoee who 
have not been initiated into the mysteries of the craft. Co- 
loon can often be removed by lemon juice, vinegar, or diluted 
ammonia. Black stains of charcoal, by rubbing the hands with 
oil and then washing them with soap and a pretty hard brush- 
Tar can be removed by oil, and rosin and lack varnish hy do- 
hoi. There are a few liquids, to wit, nitric acid, nitrate of slver, 
chloride of gold, &c., which tinge tiie skin so strongly thi^ the 
wearing off of the epidermis is the only means of removal. Such 
ic|uids must be handled carefiilly. 



°— 'Cot^gk- 



ADDITIONS 
PRECEDING ARTICLES. 



SOLUTION. 



Mohb's Comikhbbh. — A csaae of solution of Tery frequent occur- 
rence, is that where a solid substance is exposed, for a cooaider- 
able time, and at a high temimstiiTe, to the action of a volatile 
liquid, lliis is accompanied by several inconveniences. When, 
for example, the volatile liquid is valuable, as in the case of 
ether, sulphuret of carbon, &e., a considerable loss is sust^ned 
by the rapid evaporation which takes place. Other liquids, as 
spirit of wine,, undergo continual alter- 
ation in their solvent powers, by a par- 
tial decomposition. While others, as is 
the case with the nitric and muriatic 
acids, disengage vi^nrs that are very 
offensive to the operator. In expen- 
menting with liquids such as these, it is 
UBeftil to employ the following con- 
denser, for the contrivance of which 
we are indebted to Sr F. Mohb of 
Coblents. 

The mouth of the flask in which the 
solution is contained, a, i» closed with a 
cork, b, through which is passed a glass 
tube, c, 12 or 16 inches long, and J or J 
inch in diameter. Around the upper 
part of this tube is fixed another tube, 
e, by means of a cork, d. This tube 
should be nearly one inch wide, but 
only be two thirds as long as the nar- 
row tuhie. The space between the two 
tubes is filled with cold wat-er. When 
the mixture to be digested is put into 
the flask a, and the cork b is adjusted to 
its mouth, the whole apparatus may be 
fixed over a lamp, by gripping the wide 
tube e by the clasp of the tube holder, 

{age 41. The volatilised liquid, upon 
eing heated, rises in the tube c, but is 
condensed when it comes to the part 
surrounded by the cold water, and then 
flows back Into the flask. It is neces- 



278 

soiy to facilitate the droppiiw down of the condensed liquid 
from the narrow tube, bygnii£iig the point of the laitet atiant, 
ae shown in the figure, This prevents the Etccomnlation of 
liqnid in the point of the tube, as happens with narrow tubes 
that are cut off square. When the water in the tube ebecomes 
too hot to condense the rising Tspour, it must be poured oat 
and replaced by cold water. Ether can be boiled for a quarter 
of an noni in an apparatus of this sort without loss. 

When pretty large quantities of 
liquid are operated npon, a larger 
Kindenger is necessary, as the water 
n a small tube becomes too rapidly 
heated. In this case it answers very 
well to employ, tor the wide tube t, 
a two inch wide cylindrical lamp 
glass, closii^ its lower end by a 
bung. A small addition also is 
made to the apparatus to bcilitate 
the exchange of cold water for hot, 
without inverting the flask. The 
cold water is put in when neces- 
sary by a small funnel a, with a 
neck long enough to reach t^i the 
bottom of the condenser. The hot 
water is permitted to escape by a 
tube g, the lower end of which 
passes through the cork at the 
bottom of the condenser, and the 
npper end of which reaches to the 
Burfoce of the water. 

When additional liquid requires 
to be put into the flasks, the small 
fTinnel8//are employed. 

The central tubes, c, should be 
provided with corks, 6, of various 
sizes, to suit flasks with wide or 
narrow months. 

In such operations as the solution 
of platinum in aqua regia, which 
takes place very slowly, and re- 
quites a frequent renewal of the 
acid, a condenser of this kiud is 
equally economical and convenient, 
producing both a saving of acid and 

Sreventing the otherwise abundant 
iffusion of acid vapours in the 
operatoi's apartment. 




»-i h, Google 



&FFUCATION 



APPLICATION OF HEAT. 
Qas Liobt ArFARATua. 
The following figarea exhibit a set of apparatus for forming a 
portable gat light, adapted equally to the work table and flie 
lecture room, a, is a circular cast Iron table, five inches in 
diameter, and supported on three feet, each an inch in lei^h. 
This table is adapted to bold tbe cylinder of the lamp furnace, 
page 24, and therefore to supply heat in any of the operations 




for which the lamp fiimace is recommended; and, in order to 
reader gas available at various heights above the work table, 
this iron gas table ctA be raised to any requisite altitude by 
means of the table shaped branch of the unireraal support, a 
figure of which will be given under the head of " Supports for 
Apparatus," in the next section. See page S83. 

The gas is broi^ht to this moveable iron table from the near- 
est fixed gas pipe, on the ceiling, the wall, or below tbe floor, 
OS the locality may render most convenient, by means either of 
flexible spring pipe, or of soft metallic pipe; the latter bwiK 
generally preferable on account of it costing only tbe twelfth 
part. of the price of the former. You take therefore a leaden 
pipe of the requisite length. You unscrew the nozzle of the 
nearest gas light, and fasten your leaden pipe to the end of the 
gas pipe l^ a tubular connector of Indian rubber, as described 
at page 226. You then connect the other end of the leaden 
prpe,Dy another tube of Indian rubber, with tbe coupling screw 
ofyour portable gas light, which I have marked c, in tbe above 
figure. In some cases it is, however, better to have a foot or two 
of flexible spring tube cemented to this coupling screw, and to 
provide a second coupling screw to connect the flexible tube 
with the leaden tube, fixed, to be out of the way of mischief 
under some part of the work table. By means, then, of a flexible 



280 APPUCATION OF HXAT. 

metallic pipe with one or two caoutchouc connectors, gas can be 
readily brought to the coupling screw e. To this screw is 
cemented the stop cock d b, which bends at a right angle at b, 
and terminates in a gmall screw which paBses thnmgo. a hole 
bored in the middle of the Iron table a. Hence the gas can be 
permitted to esciq>e from the end b, or be shut off at pleasure 
\>y means of the stop cock d. I have consequently now only to 
dest^be the bnmeiB, or jets, which are eimiloyed to produce 
«tB flvnes of various uzes and fbmig, for dif^rent experim^ts. 
These burners are represented byfg h i, 

/ is the common single jet burner, the flame of which serves 
the some purposes as the mune of the nuall spirit and oil lamps. 

^isa thistle burner, with ten boles disposedinaring. It gives 
a large circular flame, adapted for heating evaporating ba^ns, 
large flasks, and other objects of considerable Dulk. 

A is the blowpipe burner, which I have described at page 114. 
The whole of these jets are made to flt the upper orifice of the 
socket e, which can be screwed upon, m unscrewed &om, the 
stop cock 6, at pleasure. 

« is an ordinary argand bnmer whjch gives a much more 
intense heat than aaj of the foregoing jets. It is provided with 
a separate socket and screw, adapted to the point b, so that 
when this burner is used, the socket e is displaced. A; is an iron 
chimney for the ar^and burner, which is supported when in use, 
by three thin brass wires, screwed at equidistant points into the 
burner t, as is represented at / I. Three small equidistant 
notches are cut in the lower margin of the cylinder A, to adapt 
it to these three projecting wires. The chimney is three inches 
loi^, and two inches broad, or it is two inches each way above 
the level of the burner. Th6 brass rod m, screws into the iron 
table a, but is removeable at pleasure. The use of it is by means 
of the sliding triangle ti, to hold crucibles and other small vessels 
over the flame of one or other of the jets. 

When a long narrow tin cylinder, having a row of holes round 
the bottom edge, and a flat sieve of wire gauze fixed upon the 
upper end, is put over the open mouth of the stop c04^ fi, and 
gas is allowed to miic within the cylinder with atmospheric air, 
tad is inflamed at the upper side of the wire gauze, a large, flat, 
'blne,unsmokine: flame ie produced, which can be usaMly applied 
in a great numoer of operations. 

Lamp Fubnaob. — Bince the article at page 24 — 28 was printed, 
several useful additions have b^m made to the little lamp fta* 
nace, namely ; — 

Sand Balhs. — Hemispherical capsules of very thin stoneware, 

e strengthened by a ring of stoneware round the 
edge, as represented in the marginal figuro, 
answer very well for holding hot sand so as to 
constitute saad baths for the lamp fiimace. 
Two sizes are now made for this purpose ; the 
smaUest 8} inches, the lai3:est 4^^ inches in dia- 



AFFUCATION OP BKAT. 281 

metei. They serve to regolate the aoplicatbii of heat to flaaka 
and retorts, and frequently preyent tSe fractuie of glass veeseb. 
They ate therefiire of equal nse in wlittioii and in diatillation. 
Seepage 196. 

Copper baains of the same eiiMpe are no doubt preferable for 
tluB purpose, but they are five times more expensive. 

Dome/or covering Setorli in IHtiiaalion.-—See paee 196, trad 
the additional artide on "Distillation." The prioe of this dome 

iB4d. 

Sone Oil Latwp. — This is intended to afibrd a cheap and gmtle 
heat for slow eraporationa and continued digestions over the 
sand bath. It consists of a bottle similar to the lamp a, page 
£4, bat it has a neck similar to that of the stone stU] described 
in a subsequent article, the object of the alteration beii^ to let 
the wick holder sit utfAin the neck of the lamp, in order to pre- 
vent the OTerflowing of the oiL The price of this lamp is M. 

8maU Perjbrated Eirig. — An extra perforated ring is now made 
for the lamp fnmace, in addition to the one marked e, at page 
24. It is small enough to fit into the large ring, amdii intended 
to mpport flasks and retorta of the capacity of 2 or 3 ounces, 
'which are too narrow to be held by the large ring. The price 
of this ring is 2d. 

Stone Still for Preparing Pure Water, ije. — I shall describe 
this under the head of "DistUlation," p^:e 289. 

Stone Water Bath. — See the additbnal article on "Er^o- 
ration," page 285. 

Lahos Spibit LuiF.-.-The importance of the large spirit lamp 
to the analytical chemist, has been alreadj' described in the 
article at page 19. I hare only to add, in this place, an account 
of a ectmderabk redaction in tlte price of tkis a*rful apparatus, 
which will take place in consequence of my having mauu&c- 
tured a large quantity of them. The new I^p is made from » 
pattern kindly fumiuied me by Prdessor Liebio of Oieaeen. It 
OM the form and dimeneiona which have been found to afford 
the greatest fiising power, and it is provided with the cover and 
chimney contrived by Proieasor Liebio, and alluded to at page 
20 of this work. The materia of which the lamp is made is tin 
plate, japanned brown; this metal having been found, by recent 
trials, to make a- better working lamp than brass. The chimney* 
is of black iron. The price of this lamp, without a stand, is 12b.. 
It can be fitted up on a rod adapted to support crucibles, basins, 
and flasks, at from 4a to 6a additional, according to the quantity 
of estra apparatus, and the elegance of the style of fittii^. Bee 
"Supports, in the Appendix. 

So powerfiil is the heat afibrded by this lamp, and yet so much 
'under control, that the operator has it in hia poww to use with 
effect, or to economise, at will, all the heat wnich it affords. I 
can safely say, that in consequence of this quality, it is poanble 
during a very short course of experiments, to save the cost of 
2a3 

Cooglc 



282 BvrpoKta won appae&tdb. 

the lamp out of t]ie price of the foel which woold he bnmed to 
waate in lamps of ituerior quality. I beliere, indeed, that the 
nse of this lamp is in many operatioDB attended with more ecor 
nomy than the lue of the small spiiit lamp, so great is the ad- 
vantage which attends the power of raising or depressing the 
wick according to the piogresB of the operation, an adrantage 
which is lost in the BmaJl lamps, where there is no means of re- 
gulating the height of the wick. Hence there is often a conra- 
derahle and nnavoidable waste of spirit when the small lamp is 
used. To illustrate this point, let us suppose that it is necessary 
t« apply a variable heat to an object. If you use the large lamp, 
yon give a strong or a feeble heat by simply raising or depres- 
sing the wick ; and in the latter case, no more spirit is burnt 
than the occadon requires, and both object and lamp remain 
stationary. When you use the small lamp ibi this purpose, yon 
can only give a strong heat by pulling; up the wick pretty ^'~*" 



le the distance between the lamp and the object. 1 
qiirit then boms to waste. If to prevent this, yon eadeavonr 
to push in the wick while the operation is going on, you &i« in 
danger of putting out the light, and ponibly of spoiling your 
operation. 



BUPP0RT8 FOB APPARATUS. 
Universal Support. — I have described at page 39, a powerful 
wooden support devised by Se&troem, and adapted to hold at 
TUiable heights, not exceeding 18 inches from the table, sach 
TMsels as l^ge tubes, condensers, and retorts. And at page 202, 
I haTe depicted a modification of this apparatus, as it is now 
made tot sale in Ola^ow ; what I have to add in this place, is 
a description of three additional branch holders, contrived to 
reader this apparatus of more universal application. 

It is necessary to premise that the apparatus which is figured 
at page 202, is sold in two parts. The first comprises what may 
be caUed the essential part of Seistroem's holder. It is the sort 
of Preta which is represented apart from the rod at page 99. 
The other portion of the apparatus, consists of the upright rod, tha 
foot, and the square block or parsUelopepidon of wood, by which 
the Press is connected to the rod when reqnired for service. 
The same rod, foot and block, which serve to hold Sbf- 
sthobh's Press, serve also to hold the three branches now to be 
described, each of which is famished with a round rod adapted 
to the socket that is bored in the block. 

Thb VicK. — This is a modi- 
fication of an instnunent re- 
commended byBKEizELiuB, and 
described at page 40. It is so 
contrived as to be able to bite 
both large and small tubes. 




FOB APPARATUS. 283 

Thb Table. — This branch is rather of complex structure. It 
is a combination of the set of Berzehus's supports, described at 
p&ge 44. The flat part is the table 
marked a, in the cut referred to. This 
table is five inches in diameter, sad 
servea to support the lamp furnace, 
page 24, and the gas light table, page 
279. The crook b, page 44> is supplied by two notcbea in the 
udes of the table, one adapted for tubes of an inch in diameter, 
the other for tubes of two inches in 
diameter, such as the condenaer, 
page 201. BrsBB headed nuls are 
I inserted on each side of these notched, 
to afford the means of festening the 
tubes to the table by means of string 
or thin metallic wire, slips of Indian 
rubber being put between the table and the tube to facilitate 
their adhesion. The pegs on the reverse of the table are in- 
tended t« supply the place of the pegs depicted at c, page 44. 
Thev serve to hold round bottomed vessels— basins or naaks. 

The table is pierced with two holes. One of the«e is cylin- 
drical, and intended for the support of tubes placed horizontally 
when the table is fixed vertically, as shown in the under figure. 
The other peribration is conical, and is intended to suj^rt urge 
funnels employed in the filtration of heavy masses ofliquid. 

The Cvlinhbr Holdbr. — This is neony a counterpart of 
Oahn's holder, described at page 222, fig. B, But difEers from 
it in beins without the cavity and screw r n, and consequently 
without the supporting rods d i, in the place of which a long 
peg is fastened upon the instrument at the end a b, by which 
it can be fixed to the block of the upr^ht rod described above. 
Any other variety of branch can be adjusted to the univer- 
sal support in the some manner, accor£ng to the particular 
object m view. 

Lamp Rod and Holder for Evaporatinq Basins. — At page 37, 
I recommended the practice of securing triangles intend^ for 
the support of large evaporating basms, by fixing them to 
upright roda by means of screw nuts; but I committed the over- 
sight of not describing the 
screw nut, which is best 
adapted to that purpose, 
which o ' ' 




mch in diameter,hared with 
, a hole, for the reception of 
a brass rod of J inch in dia- 
meter, to which rod it can 
be affixed by means of the 
flat headed screw b. A brasi 



rod fuch wide, and 1 incli Iodk, is fixed to the sphere at a right 
angle to the bore a, and a fenule screw o ia aunk in the end of 
this rod for the reception of screwB cut npon the ends of wire 
triangles, lamp lodi, and other instnunents which require to be 
supported horizontally. 
The following articles are requtaite to complete this ^^luatni : 

1. A brass rod, 18 inches long, and about } inch dimeter. 

2. A foot, consisting of an oblong board, as represented at 
page 19, or a cast iron triangular trivet with three feet, which I 
hare now in course of manumcture far this purpose. 

3. Aglazedearthenware pan, of 8 or 12 inches diameter, and 
1} inch hifh, fixable to the foot, and intended to catch any 
liquor whi<£ may be spilt over, and so prevent the loss of the 
liquor and the s-uling of the table. 

4. Branches to screw into the socket to support various ob- 
jects; as a square iron rod to support the large spirit lamp; a 
ring to support a sand bath; a trianj^ to support a basin, Sec. 



TESTING. 

Daomtta Tubes. — Refer to the figures on p^;e £6. In cases 
where tests or other liquids are to be applied in siDgle drops, the 
tubes by which they are transvased should be wide at one end 
Uld nearly closed at the other, the orifice left open not being 
above ^ inch in diameter. This has been already explained ; 
but 1 have omitted to state that it ia the vide end of the tube 
which should be dipped ijUo the lignid, so that the test bottle, 
figured on page &8, is misdrawn. The tabe should be inverted, 
and the contracted end project above the cork. The applioatbn 
of liquids in drops by tnia method, will be found very ea^ to 
tnuiage. 

It would hove been mentioned at page S8, that the dropping 
tube with a bulb is useful, when you have to remove liquors by 
suction from above powdeis without disturbing the latter, and 
also when liquids have to be removed from a flat soi&ce, an ex- 
aqiple of whidi is given at p^ 212. 

Ih?rovri> Tube Fkahg. — The tube &ame depicted on p^es 
51, 52, has been farther improved byraaking the pegs of yellow 

f lazed earthenware, and the rest of the apparatus of polished 
lack wood. Thus constructed, it is much easier to keep cleffia 
than when made throughout of white wood. The price of it 
thus improved, namely, of the large size, with 8 pegs for 6-iuch 
tubes, is 2s. 

Stock Tdbk Rack. — I have constructed a tube rack for hold- 
ing three dozen of tube vessels for use in a Laboratory where 
such vessels may be often in request. It consists of a black 



FILTEATtON- 

wooden fiMt, with fbnr towb of glazed yellow earthenware pegs, 
each row containing nine p^ of the Mowing size:— 

1st row, 1} inch, \ inch thick. 

2nd TOW, 2j inch, | mch thick. 

3rd row, 3 inch, | mch thick. 

4th row, 3J inch, J inch thick. 
Thb rack will contain tube yeaaels of all the sizes which are 
commonly used to hold liquids. It should he considered a fix- 
tnre in the Laboratory, and when the tubes are reqnired for 
use, they should be transferred to a tube frame with hoIeB. 
Bmaller sizes of tube vessels than those adapted for the above 
rack, are generally used for dry operations, sublimations, &c., 
and ehoold be kept along with the blowpipe apparatus. 



FILTRATION. 

Bekun PoROBLtiN FuNFfxL HoLDBs. — ThiB instrument is of thc 
shape and size of the earthenware funnel holder described at 
page 67. It is of white porcelain and glazed on the upper snr- 
&ce and in the ring r, but not in the hole rv>. It is fitted np 
in the style shown at page 66 (the lower figure). The rod and 
foot are of polished black wood. The rod is nine inches high. 
The price of the apparatus, complete, is Is. 6d. 

In the figure referred to at page 66, the upper end of the rod 
c is represented as pointed. It ought to be flat, because it is 
often neceeaary to alter the position of the part b and d with 
the finders of the right hand, and it is then necessary to steady 
the rod c by pressing the thumb upon its top. This is a small 
matter to refer to, but good manipulation conmsts in attention 
to small matters. 



EVAPORATION. 

Stonbwarb WiTEE Bath. — The water bath described at page 
89, I have now imitated in stoneware. The size of it la 4J 
inches diameter. It can be used very conveniently with the 
lamp fomace. The price of it (two pieces) is 9d. 

BTONEVfARB Etaporatimo Babins. — I hftTO SDCceedsd in pro- 
curing a supply of evapoTating basins of salt glazed stoneware. 
They are mostly shaped like the third variety of the Berlin 
porcelain basins enumerated at p^e 8fi, being one third as deep 
as thev are broad, and having an overhanging rim; and only a 
few of them have spouts. Tliey are very thm and uniform in 
substance, and well glazed. They can be heated over sand, or 
even over the flame of the lamp if applied cautiously, fot 



Cooglc 



S86 IGNITION. 

■low ev^toration and for cryatalliBation the^ answer extremely 
wall, eqieciallj for the Utter, as the ilight TOughueflBM on tbe. 
BUT&ce facilitate the depoaition of crratalB. Thev cau also be 
uaed in evaporatiug to diyneas, proriaed the heat De moderated 
towards the end of the process. But they cannot be heated to 
dryness in contact with the point of a strong' and steady spirit 
flame, without a chance of splitting. This chance is greatly 
diminished by placing the eraporating basin over hot sand, con- 
tained in a stoneware sand bath, or by fixing the evaporating 
basin at some height above the flame when the solution is con- 
oeatiated, so as to cause the snbstance to dry gradnally. 1 
employ short cylinders of stoneware, to lengthen the lamp fiir- 
lutcc v>t this purpose. 

These baains are not adapted for use in accurate experiments 
with weighed quantities; but they will probably prove useful in 
the preparation of many chemical substances; as, for example, 
in the pharmaceutical processes wliich occupy the attention of 
practical students of medical chemistry; in the evaporations 
which BO frequently occur in the laboratories of monu&cturing 
chemists; in the preparation and examination of dyestufis ana 
drngs in the colourshops of colics printers; and in many other 
casM of equal importance. 

The sizes and prices of these stoneware basins are mentioned 
in the Appendix. 

H1SDI.B roR Basins.— It is sometimes necessary to lift hot 
basins, for which purpose the tin holder, figured on page 41, is 
a useful instrument. Yon hold the end a in your right hand; 
grip the edge of the bamn between the bent ends b, and secure 
it there by poshing down the coil o by means of the thumb and 
fiirefinger ot the right hand. However, this method of lifting a 
baun can only be used when the basin is small, and not very 
full of liquid. 



IGNITION. 

New Berlin Poroeliiih Crcoiblbb.— 5ince -the description of 
Berlin glazed crucibles at page 98 was printed, I have receired 
two new sorts. The torm of these is cylindrictd, like the figure 
ofthelittlecniciblein the jacket on page 97. The cover is dif- 
ferent from the cover depicted on page 98, inasmuch as the per- 
pendicular rim which holds it on the crucible dips inside the era- 
cible instead of covering the outer edge. There are two siaes of 
this new crucible : — 

No. 1. — IJ inch by 1 inch, price 8d. 
2.— If inch by IJ inch, price 9d. 
These ate the prices in Glasgow. 



BLOW PI FX APPARATUS. 



BLOWPIPE APPARATUS. 

Boxes for FLDXEi and ArPiRiTOB. — At pages 127, 128, and 
ISO, I hATe ducribed several methods of packing Mid arraiigiiig 
the utidesieqnind for use in analyds by tbe blowpipe. To the 
accounts there given, I now add another, rektivo to a pair of 
hoses which I have recently contiived, and find to be oon- 
renient. 




The figure represents a box S inches long, 6 inches broad, and 
1 inch deep, divided by fixed partitiouB into six diviaioDS. It baa 
a cover which lifts off, and forms a tray to hold the lamp when 
in use. The box and cover aremadeoftinplate, japanned both 
within and without. 

The largest divinon contains the blowpipe fitted ready for use, 
the platinum tongs, the hammer, the charcoal borer, tho char- 
coal nolder, the tongs far trimming the lamp, the rod for sup- 
porting the lamp when the latter is dismounted, the file, and 
other small tools, all disposed, as shown by the figure, bettar 
than I can tell in words. Another space contains about two 
dozen of 6 inch hard open tubes for subhrnation ; another, ludfer 
matches, or, in their place, substances for analysis ; another, the 
acate mortar ; another, the anvil ; and the last space contains the 
platinum wires and' foils, the brass wire, the closed tabes, and 
other small supports. 

This cut represents a box with di- 
visions for fluxes, and prepared 
plates of charcoal. It is made of 
japanned tin plate like the foregoing, 
and provided with a cover. It is Si 
inches long, 4} inches wide, and 
nearly 2 inches deep, a s m, re- 
present a space for three square 
glass bottles to contain borax, soda, 
and microcosmic salt. The bottles 



0^©1 


il 


0© 

Charcoal 



288 DISTILLATION. 

w]ueh I OBC for this pnrpoae are the sqoare inb bottl^ com- 
monly used for portable writing desks. They are closed hy 
corks with platea tops. Below this space is another which holaa 
about two dozen of prepared platee of charcoal, and a third space 
which contains about a dozen of 2J inch glass tnbes, closed by 
corks, for storing the remainder of yie rerSgents, viz., test paper, 
nitre, and the other subetaaces particnilariscd at page 127. 

When at home, yon alw&ys 
keep yonr lamp monnted Kftdy 
for use on snch a stand as is re- 
presented in the annexed figure, 
which stand is umply a wooden 
rod fixed into a paraUelogram of 
■wood. There is therefore no oc- 
casion to provide any place for 
the lamp in either of these boxes. 
I In travelling, yon have to take 
another sort of lamp, provided 
with a screw cap to cover the 
wick holder, and prevent the esct^ of oiL This lamp you 
make into a separate package. A wooden rod for supporting it 
can be carried in the lar^ dox alongnde the hammer; and to 

Sroride the means of fixing the rod, a small tin cylinder is sol- 
ered upon the inner side of the cover of the lai^ box, by 
means of which, and an intermediate cork, the rod and lamp con 
be fixed upon the cover, as upon a foot. Hence it is uni 
isiy to carry about any separate basis for the lamp rod. 

The price of this pair of japanned boxes is 7s., orwitha 
plete set of apparatus, 428. 




DISTILLATION. 



STONEWikits BniL. — The annexed figure represents a stone 

ware still, or a vessel betwixt a retort and a stQl, which will be 

found useful in many common cases of . distillation, such as the- 

preparatjon of distilled water, the 

t f — .^^^^ purifi-cation of muriatic acid, and 

^~W »^^~^~--..^ * treat number of other proceaeea 

ft y \"^~"^~-^^ which I shall have abundant op- 

JV \ d portunities of showing hereafter, 

n rfl —a is the still, h the tubulure, d 



, inches, the capacity 1 . 
ounces, c is a cylinder of the 
same material as the still, 4 inches 
high, 4 inches wide, open at both 



ends, and uritb a fixed rim at the top, adapted to mpport the 
still in the maimer shown by the figure. The atoppet for the 
tubuliue b is peculiar, and is ior 
the Bake of penpicuity r^reeent- 
ed in the margin in its mil size. 
A A indicate a section of the tubu- 
lure b, and show the substance 
and proportions of the neck. — 
The shaded mass b, is a section of 
the stopper, and the spaces c c, 
lepreeent a moss of plaster of 
Paris, which is poured in above 
the stopper to make an air tight 

Inatructions for DUtilUng Water 6y mean* of Ms Slone Still, 
Poor into the still eight or ten ounces of water. Close the 
tubulnre b with a cork. Then take the lamp a, the cylinder 
b, and the ring top e, of the 
lamp furnace, described at 
page 24; the stone dome 
for distillation, described at 
p^ 196, and of which a 
figure is given in the mar- 
gin ; the pnenmatic trough 
described at page 214; and 
a small wooden stool with 
three legs, or a small box, 8 or 10 inches in height; and 
arrange the whole as shown by the figure in the mai^in. « is 
the stool, a is the pneumatic 
trough, b is the lamp fur- 
nace, e is the ring top of the 
furnace, d is the cylinder 
which serves to support the 
still, and which differs from 
the cylinder of the fiimace, 
in bemg shorter and without 
air holes, c c c, is the still 
in one piece, f is the dome. 
All being thus arranged, 
lift up the cylinder d, light 
the lamp b, replace the still 
upon e, and let the appa- 
ratus rest till the water W 
eins to boil, which will be 
m a few 







m 



... . . -lole appa 

sufiicient height above die table to permit the still to 

niently connected with a condensing apparatus, of which I shall 

speak presently. The use of the trougE a, is to receive the ooa- 



290 DISTILLATION. 

tents of the still if it should break. The use of the lamp cylin- 
der and ring b snd e, I hare already suffidently illustrated. The 
use of the cylinder d, and the dome /, is to retain a maea of hot 
air ronnd the entire sor&ce of the retort, and bo to promote a 
rapid evaporating within it, which porpose this arrangement ae- 
comptishef). In a short time a strong current of steam issaes 
from the neck of the BtUl. The condenser described at page 201, 
previously filled with water, and properly supported by the 
holder described at p^;e 20S, is then o^usted to the neck of the 
still, and a flask is placed over the lower end of the glass con- 
densing tube, for the purpose of receiving the distillSl wat«r. 
No other care is then required than that of keeping the con- 
denser duly supplied with cold water. By means of this appa- 
ratus, and the small stone spirit lamp, or a single jet gas flame, 
pure water can be prepared with great fiicility. 

To purify Muriatie Acid by mean* of tkU Stiil. — According to 
Professor Clark, the best method of puritying muriatic acid is 
to dilute it to the specific gravity of 1111 ; to add a little proto- 
chloride of tin, or a little metalUc tin, and then to distil. Acid 
of this specific gravity vaporises without either gaining or losing 
strength. 

The diluted acid is to be put into the stone still, the tnbulnre 
is to be closed with its stone stopper, md cemented air ti^ht with 
plaster of Paris, which is to be poured in a l^uid state mto the 
cavity c c, over the stopper in the tubulure of the still, as I have 
mentioned and figured at page 289. 

The distillation of the add is then effected in the same man- 
ner as the distillation of water. 

Metallic Still roa Distillino Water and Volatilb Oub. — 
The figure in the margin represents a small still formed of tin 
plate, which can be employed to distil 
er, alcohol, and odoriferous oOb, in 
^ . . manner described at p^es 187-191. 
' This still consists of two parts, a and a. 
The former is a cylindrical pan, 3 inches 

\ high, and 3 inches in diameter, with a flat 

I rimhfi 




._ it outwards, as shown in the figure. 

B is a conical head, 3 inches high, and 8 / 
im^es wide at the base, with a horizontal 
flat rim and a vertical rim, both repre- 
sented in the section, and adapted to fit 
closely to the sides and the flat rim of the 
pan A, so as to prevent the egress of 

steam at the juncture. The head is provided with a neck to 

convey steam mto a cooling ^paratns. 
When employed to distil water or alcohol, this still is mounted 

in the same manner as the stone still which I have just described, 

and as figured on page 289. 



Wlien employed to distil volatile oils, tke brass or tin plat« 
disc represented at page 189 is employed, for the purpose de- 
scribed at the place referred to. The distillation is commenoed 
in this case with about an inch depth of water in the pan a, 
below the perforated disc. The cylinder d, and the dome /, 
are of precisely the same service when used with a tin as with a 
stone still, lae flat rim round the upper edKe of the tin still 
should sit BO closely upon the upper edge of the cylinder d, as 
to prevent the passage of hot air Detwist them. It should also 
be of such a size as to affoid a resting place for the dome J^ p^e 




DISTILLATION OT POTABSIDM. 



t, Google 



t., Google 



APPENDIX. 
PRICES OF CHEMICAL APPARATUS 

CABINETS OF ROCKS AND MINERALS, 
RICHARD GRIFFIN & CO., 

BOOKSELLERS AfID STATIOSBBS, QLAS60W. 



CuDNTBT orders, accompuiied by \ rEmltUnce, will ba promptly eie. 
— *"d. The" eipenae of pAckfng c&aes *- <.t-*.„^ui„ : — jjr.j^^ ._ »l_ 
J of tbo articJoSr ftt the nte of Kbout 

I of packing is soinawtiathi 



when tbo ordsr conlains mmy Tary bulky or tbij fngile si 
of packing is soinawtiat higher. Ihe greateEt em's wl 
the goods securely ; but R. G. & Co. do not hold then 



sponsible for the breskaga which miiy bsproduced by ti 

o&rriers* Gooda can be fonvuded to Emgluid by steun to Liverpool, 
— "^ thence by nilwiiy or canal; or by canal to Leith, and thence by 

m or smack to Newcastle, Hull, or LDUdon. Nacluirge is made (oj 

shipping the goods in Glasgow, 

Ueilen in Philosophical apparatus will be supplied at a Tery liberal 
rale of discount for prompt paymen* 

Gentlemen irho may be inclined to purchase this apparatus of dealers 

residont in towiu at a distance from Glasgow, ar —j-j -i— ■ -t- 

prices of the articles must necBssarily be higher 
quoted in this catalogue { because the dealer in e' 
be compensated for hjs charges of packing, carri 

breakage. The prices here given are the pricei „ . 

charges of transporting the apparatus to a distance falls unavoidably 



The pages referred to in " ChUitcal Rscbeations," present fignres 
or descriptions of the apparatus. 

.. hen no price is affixed, the article is In course of manufacture, and 
the price not ascertained. Such omissions will be supplied by the pub- 
lication of > aapplementary Catalogue in Va» next part of Chuiicai 
Recreations. Many of these articles will, however, be ready for sale 
In a few weelis or days. 

Written orders for apparatus Ihim this Catalogue should contain the 
littttt and Jigirei prefixed to the desired articles, to prevent misappre- 



i,Goo;jli: 



OBIFFIN i OHXMICAL AFPARATUi. 



A.— APPABATUS pob PULVERISATION. 

Anvil rorBlimplpe Eiperimenti, tqnira Modi of hard- 
ened iteel, pies 4, .... 
Steel Hunmei' Ar ditto, pagei 4, ItS, 
Agate Mortar toi Pestle, page 3, 11 Inch dlunetei. 
Ditto, ditto, S ditto, 

r r V z : 

null BerKn Porcelain Fastle and Mortar, 1} Inch dia- 
meter, and shallow, glared irithln, for blowpipe ei- 
periments, in llou of Agate Mortar, . 

lerlin Poi^elaln Mortars with Pestln, glazed wlthonl, 
blBcuit within, the pestle! in one piece, page 3: — 



No. 0.- 



Ditto, 



pageS:-^ 

No. 1 — 51 inches diameter. 
Ditto, 8.-71 ditto, 

3.-9 — . . , 

Serpentine Mortar and PeEtle, very^fineljr pollabed: — 

8 inchet diameter, , ' , 

Ditto, S ditto, . . . . 

— 4 — 



B.— APPABATUS FOR SOLUTION. 

Flint Qara Fluki with thin Ijattama, for boUIng Mlu- 

tions, the lips not turned: — 
With flat bottom, 8 ounce. 

Ditto, 4 — ... 



With round bottoin,8 — fig. A, page U, 

Ditto, 3 — pear shaped, with long neck, 

fig- e, page 8*, 

— 6 — with long neck, ditto, 
Hard German Glass Flasks, olth thin bottoms and bw- 

dered mouths, for the reception of corks, and there- 
fore equally adapted for gas bottles >— 
8 ounce capacity, 
Ditto, 3 ditto, 

— 4 — . 

— 6 ~~ . 

— 10 — . 



c s 

C 8 

C 4 

C 6 

C 6 



C 9 
C JO 
Cll 

CIS 
C13 
Cll 



ORIPPIN a CBXMICAI. APPARATUS. 

Boiling Tube, six inchea by one inch, hard Gennui 
glass, sealed and bordered, intended for the solution 
of mattls, kc , on the small sciJa, fig. c, page 8, 
See " Teat Tubea," for other alios of tube vesaeli. 

Ditto, with round bulb, pue 8, bard glass, 
^^ with peir shaped bulb, pUB 8, nard glaaa. 

Oval Flaak, with turned lip tot the reception of ■ cork, 
G oi. t]int ilaai, page S09, upper figure, 

3erlinPi '' ■ •'^- ■ *■ ■ 

nlden: 

Small Blie.'Si bj 1} inch. 
Ditto, Luge g|i«. Si by S^ inch, 



C— APPUCATION OF HEAT. 

LAMP FURNACE, pages 84, SSO. 

Stoneware Spirit Lamp, with carer am) tin wick hiridec, 

page S4, a, . 
Cylinder foe ditto, aerrlng as a chimney to steady the 

ilanie, and aa a aupport for vesaels orer It, page S4, b. 
Fire Inch Ring Top for ditto, pace 24, c, page 25, III. 

serves to support 4 oi. to 8 oz. flasks. 
Three inch Ring Top, to contract the ori lice orthe former 

ring, and support z oz. and 3 oi. flasks, page SSI, 
Dome to cover Fla^ when boiling, and prevent the 

radiation of heat, page SI, il. 
Sand Bath, 3^ inch, for small flasks and retorts, ad^ited 

to the large rlnf tup, page 880, 
Sand Bath, 4^ inches, a<b.pted to the top of cylinder C 8, 
Dome t(j cover 8 oi. to 6 oi. retoita In distillation, 

when placed on the ring top or sand baths, and pre. 

vent condenaatioD in the upper part ot the retort, 

pages £81,889, 

Water Bath, 4^ inch, for drying powders at a steam 

heat, adapted to ci^inder (J S, in two pieces — bailer 

and capsule, page 886, . . . . . 

Oil Lamp for thia Fufluce, to be used in slow evapora- 

tiona and digestions, with wick holder and cover, 

page SSI, ...... 

Set ofthree Plain Cjilindera of different sizes, tolengthen 

the cylinder C 8, and adjust vessels at proper heights 

from the lamp, and thus modify the inten&it/ ol the 

heat applied, ■ . . . ihi iH 

Still or Stiqipered Retort, adapted for the distillatiDn 

ofwaterorafacids, 16os. capacitv, paae l"" 



Flask with round thin bottom and wide mouth, for 
prepari^ such gases aa require heat, 6 oi. to 10 oi.. 

Another Flaak, with thin round bottom, adapted for the 
preparation of acids, with a neck such as is describe-* 
at page S89, 18 OS. 

Another Flask, with thin round bottom, J8 oi., with _ 
neck 8 inches broad, on the same plan as the last, and 

Ml tluabm liarHclei art made qf 'all glated itmei 



C16 

C17 
C IS 
Cld 

C!0 

C2i 



cse 

087 
C28 



D 1 

D 2 

D 3 

D 4 

D 5 

D 6 

D 7 



SKltrlM'a CBBMICAL APPJLRATD8. 



Iron TtbUIi for lupportfnf cipBules and flat bothHned 



, omitting the trtides 



ilutions, BViporatioiiB, uid igu!- 
tioiu, tIz., C 1 to 7, and 1G to is, 

Lakob SriBit Lamp, with cibculab vice, with the 

Improveinents of Berzelius, Mltuharlich, and Liehig, 

Jipuined tin plate, with iron chimiie]', pages IS, SSI, 
Cotton Wicks for this lunp, . . perivm, 

Crurible Jacket to Increase the igniting power of the 

lamp for crucible operations, 

Gab-Lioht FiTTtHca, p>ge£T!L 

Stop Cock »nd Couplina Screw, 

Iron Table, with Brass Hod and Triangle, . 

Socket and Single Jet, 

Thistle Burner, 10 holei, 

Argand Biinier and Iron Chimnej, 

Blowpipe Burner, page 114, . 

PleiAle Pipe, seven feet long, 
Cost of Che whole gas fittings, C SE to 91 , 
Glass Spirit Lamp, with cu and brus wkk htdder, 

page f7, a ounce, .... 
Ditto, 4 ounc 



withasilverwlck bolder, sAor Berzelius, 4a. 

Tin Spirit Lamp, with coyer, pace 18, 
Jspanned Tin Oil Lamp, with ccrer, page 18, . 
Stoneware Furnace for Bvaporation, to be used with 

StORBWBie' Furnace far Distillation and Crucible' Operal 
' ions, to be used with charcoal. 



D.— SUPPORTS FOR AM»ARATUS. 

Triangle Support for Retorts, CmciMes, &&, page 3Q, 
9 iiifh hrasB rod and triangle, with wooden foot 

Tabo Hdder for supporting small glass vessels above a 
lamp, pace 43, Japanned irun, with noodttnnid and Ibot, 

Tube Holder without the rod and fool, ■ 

China Funnel Holder, adapted for »nv sfie of fonnel, 
withwoodenrodaod root,pageOS,S7, 

Ditto, entirely made of wo«>d, . . . . 

— the branch of Berlin porcelain and the rod and 
foot of psllshed black wood, .... 

Set of Six Bocks of Wood, for adjusting apparatus, 4 
inches square, and respectlTely i, 2, 1, }, i, | inches 
Chick, page 30, . . iheitl 



Support for Blowpipe Lamp, "ooden rod uid foot, bl&fk. 
Universal Support, comprising a woedeii foot and IS Inch 

rod with nut and screw, and four branches to support 

apparatus ot various fomu,; page S82, made of hard 

wood stained black: — 

The Rod, Foot, and Nutt alone, 

The I'&ble Sh&ped Branch, . 

The Vice Shaped Branch, 

The Press Sliapcd Branch, 

The Cylinder Holder . 
The Set of Supports, D 9 to IS, coi 
The Bame, vamiBhed with copal Is 6d additional. 
The rod D 9, and any branch supnlied Eeparately. 

SOFPOKTS FOB LaRGB SpiRlT LaHF, BaSINS, &C. 

Cast Iron Trian^lar Foot for retort stands, measuring 
5 inches each side, with three feet an inch liigh 

Ditto, measuring H inches each side 

Brass Rod 18 inch, for the large fool, with screws tofii it. 

Brass Rod 12 inch, for the small foot,with screws to Ri It, 

Glazed Earthenware Pan, to place upon these feet below 
lamps, basins, &c.,5 inches diameter, Jinch deep, 

Ditto, 6 inches diameter,! inf'- ^- — 
— - 12 inches diamef ' " ' 

Socket ai 






The SefiaLamp Supporu, comprising D 16, 17,81, three 

of 22, 23, 8*, 

Set adapted merely to hold the lamp, D 16, 17,28, 84, 
Square Iron Bar, with wooden rod adapted to U 9, 
support the Large Lamp, C 22, 



Test Tubes, hard German glass, straight, se 
end, bordered at the mouth, page H, c. : — 
■1 inch long by 8-elgliths inch wide, 
11 — isiiteenths — 



3-eightbs 
1-hJf 
1-third 
1-half 
8- fifths 



1-half 
S-eighths 
S^ightiia 
S-elghths 



— 3.(our 



APPARATUg. 



»ith (talk uid 



without lip or sUlk, p&ge fit, 



i Clark's Conical Test Ulsss, 1 

lip, pwe 53, 
> Conical Test Glass, J 
) Conical Test Glass, * 

PniDB for S Large Test Tubes with p«gs for t 

page 61, while irood, 
Frame for 8 Larie Test Tubei, polished black wood, 
~ .h glaied j'ellow earthennare pegs, 
I, varnished with copal hard vamith, 
■ for * Test Tubes, with glaied yellow stone pi 
' Frame for 6 Test Tubes without pegs, page SO, 
i Stock Hack for Tubes, consisting of 96 glaied yellow 
igi, adapted for lubes lyom 8 Inch to 6 Inch, 

a black wood base, page £84, 

Flint Glass Rod Stirrers, prepared at tJie ends, page 46, 

3 Inches long, I-eighth Incli wide, _ . . .. 

6 — l^ixth -. 

9 — 1-filth — 

Flint Glass Rods, for Stirrers, in lengths, not prepared. 

Thick, per yard. 

Middle, — 

Thin, — 

I Dropping "Hibe, with Bulb, page 57 

I Dropping Tube, Plain, 6 inch, page 6t 

Test Books, each contaliung 501eaTi 



banker's cbequ 



^hbmt. 



. . tlue LlUnus test papers, 

Book of Red Litmus, 

Book of Turmeric, 

Book of Brazil Wood, 

Book of Acetate or Lead, 

inch Iron Bar, for metallic precipitation, 

inch Zinc Bar, — — 

Inch Copper Bar, — — 

i^opper Wire, for precipitation, per yard, 

F'oll, for Ditto, 10 square Inches, . 

Test Spoon.—a small spoon with a bowl ^ inch diame- 

ng small quantities of powder; the handle 

spatula, polished albata. 



»-i h, Google 



E73 
E74 

ET5 



Set of G8 Bottlea tit Row's Tests, 3 ud 6 

in Latin in bluk enunel. 
Battles Tor Re-agents, made Kcording to the shape 

descrlbed-at page S6, flint glsa); — 
I ounce, uuBtoppered, 

Ditto, i ditto, ditto. 



Eitca Strong Bottles for Re-agonta, flint glass: 
1 ounce, not stoppered. 
Ditto, « — _ . . 

— 2 — itoppered. 



auth. 



stoppered. 



GtsBS Caps for Acid Bottles, page 56, 

Stoneware Caps for Acid Bottles, 

Stmewtre Battlea for Drugs, with wide mouths, 

Bounce, . pirdowen, 

Ditto, S — . — 

Corlia for the 8 ounce Stone Bottles, • — 

Ditto B _ — . — 

Frama for holding s[i Acid BotUei, 4 ounce, page 60, 
Prama for holding eight TaEt Bottlaa, 3 ounce. 
Frame for holding six Test Bottles, 3 ounce. 



F.— PRECIPITATION. 

Beaker Glasses, (boll shaped) for hot liquon, as re 
mended bj Berielius, thin at sides and bottom. 



The Set ofnine Beaker Glasses, packed in airoodenbox, 
Bohemian Beaker Glasses of hard glass, stronger 
better adapted for holding hot liquors than thosi 



flint glass,' all lizei, one-Aalf hi, 

Cylindrical Jua of flint glass, page 6! 

8 inches high and 1^ iocbes wi 



; Coogic 



ORirriN B cHxuicAi. 



G.— FILTRATION. 



O 2 
G a 
G 4 



No. 1 ij Inch diameter. 



Gil 
GU 
GI3 
OI4 

GIS 

Gie 



GI7 

Gia 

GI9 
G80 



Funnel Holder, consisting of chini ring, "'ith rod uid 
foot of white wood, page 66, lower figure. 

Ditto, of polished hlMkwood, . 

Funnel Holder, nith wooden ring, . . 

Funnel Holder with Berlin porcelain ring, and polished 
black wood rod and foot, page 66, G7. t»3, 

Circular Filters, prepared from very pure paper, w 
cuntaina no soluble matter, glTes only one part ii 
of aahes, and filter! with rapidity. Sold in packets of 
100 filters each, in aizes to suit the foregoing siz" - ' 

No. 1.— 81 inch diameter, per 100, 
- 8.-«l - - - 

__ 3.— 3a _ _ — . 

_ 4^1 - - - . 

_ 5.— 61 — _ — , 

_ 6— 7i — — — . 

Filter Boies of six sites, corresponding with the abore 



and the flunl'er of the fun 

gold both on the front and 

No. 1 Tor fillers Nt 



1 Price 01 



G86 
GW 
GSe 



Set of six FuimelB with best fumie 
aiidasetof6boies, each with 100 filters, 

Price of a Set of Nas. 1, S and S, complete, with com. 
mon china funnel holder. 

Ditto, wfth best Berlin tunnel holder 

Clark's FllteriogRing,one inch diameter, page T8, glass. 

Ditto, lialfin ■ " * • — 






h diameter, glass, page 72, 
I diameter, glazed chini^. 



H 8 

H a 

H 4 



H .— EDULCORATION. 

BerzeliuB's Washing Bottle, with tube, for the edulco- 
latlon of prertp Hates, by a fine but strong curre. 
water, page SO, ounce. 

The glass Tube separately. 

Stone Washing Bottle, trltbaglasi tube, 4 ounce 

"- B Washing BotUs, 6 oz., wltli albaU tube. 



Glus Washing Battle, & oz., with an iilluts tub 
contrived u Co dispense with a connecting cork, and 
thus obviate the occasional stopping ot the tube by 



tube, complete, page HI, 
ierzelius's Tube for suppl} 

' to wash aprecipiti 



i, made of albata, less tVif its, with glass point 



I.— EVAPORATION AND CRYSTALLI- 
SATION. 

Evaporating Capsules of Berlin Porcelain, with spread. 
Ing edge, glazed throughout, pages 3S, SO. A tew al 
these basins have no spreading edge, but are provided 
with a apout. At present, however, they no longer 
make them at Berlin with a spout. 





TAi df]>lh i, one-lhitd of th, «Hilh. 












00.— 2 Inches, . 






6.— 6 inches, . 








S 






I.— 3 — 






























4.— 41 — 








i 7 




1 


1* 


la— I5J _ 


llfi 


Nest or 4 Berlin Parcel^n Capsules, Nos. 00 ta 2. . 




NestofB — _ _ „ OOtoB, . 


117 


Nest of 11 — 


- 


— 


- 00 to 9, . 



Svaporsting and CrTstallising Capsules of salt glazed 
stiineware, made very thin at the bottom and with 
spreading edge. Can be heated over hot sand, or over 
the spirit lamp; useful for crystallising. In conse- 
quence of the slight roughness of the surface ; also for 
the evaixntion of quantities ofsallne solutions, which 
can be carried to dryness. It effected slowly upon 
one of the lengthening cylinders, C II. 
Depth ont-third qfllK diamrter. 



ajin 



. Si. 



I 84 
I Sfi 



6 — 



I CHBMICAI. AFPAU-TirS. 



Hemispheilcal Bttlln Porce1*in Evipontiug Buini>- 
T)u depth 11 half the itidth. 
Ha. 000 I Inch diuneter. 



4.-7J - 

5.— 9i — 



with spout, 
irstlng Basins of tha hemispherical 
.er, 2 inch da«p. 



pi"™. . . 
lunp funuco . 

No. 1. — i inches diametBi 
2._8j _ _ 
3.— 3j — — 
4, — I J inch diuDcter, jetj light, forireigh- 
Inf the product of ui eTsporttioii to dryness, 
BerlTn Porcelain Water Bath, page B9, employed to dry 
powden, &c. — cm be used over the lamp furnace : — 
No. 00.-4^ inches diameter. 



Berlin Porcelain Cups of thin sidtstance, ilaied, fo 
evaporation to dryness, ignition, and weiring: — 
No. I . — I inch wide, 1 inch deep, 
- 2,_J _ i _ . 

_ 3,-li _ I _ . 
Berlin Porcel^n Shallo" Plates, for evaponition, intend- 
"* to replwe watcli glasses, glaied: — 
No. 1 — li inch diameter, 
-- 2._|j _ _ 
I Platinum CBpsule,>ith spout and handle, pages 13, 14, 
1 inch diameter, one-third inch deep, 
atinum Capsule, IJ, inch wide, three.lOths Inch deep,. 
Ditto, nitli orerlianglng edge, 1^ inch diameter, 
— — — B inches ~ 

.alinum Hemispherical Cup, with handle, i in. diam., 
Ditto, _ _ _ S — 

> Platinum Cup, with spreading edge, after Beriellus', 
page 14, 3 inch diameter, .... 
Platinum Stirrer, oi Sp&tula, for the small capsules, 
round wire, 11 inch long, one-Soth inch thick, 
I Platinum SpatuU, flattened nire, Dne-Bth inch broad, 

one. 20th inch thick, ! inches long, . 
: Platinum Spatulas of ■ larger siie, charged by weight. 

K.— IGNITION. 

in Porcelain Crucibles, glazed, conical form, with 



GRimN'S CBBHICAL APPARATUa. 303 1 




Berlin Porcelain Cruciblss, glazed, cylindrical form, 




d. 




"■itt cotar, pige 886, a new paltem :— 
liinchiigh, byl iDchwide, 






K 3 






K 4 


li inch high, by 14 inch wide, 
Beiiin Porcelain Bfscuit Crnciblea, for fusing nitrate of 




£> 










sllTcr, be., with perforstod coTcr to allow the escape 








ofgaaes,pagB99:— 






K 6 


gilnchea high, hy li inch wide, 
31 inches high, by 2 inches wide, . 
Triangular Hessian Crucibles, without covers, page 99: 






K 6 




9 








K 7 


Small nest of 3 Cnicihles, B to 3 inches high. 




5 


K 8 


Small nest of 5 Crucibles, 1 to 4 _ 




9 


K 9 


Large nesCofS Crucibles, 8 to 5 — 


1 




KIO 


Black Lead CruciWas, page 100, 3 inches high, 




4 


KIl 


Ditto, ^ inches high. 






K18 


Pbtinum Crucibles, London made, without corer. 






13 


Ditto, iive-eighlhs — . 






H 


— three-tourths— . . V Ba. to 


18 




16 
16 








17 


Platiuum Crucible, with coveril inch deep, ' -J 






IS 


Ditto, 1} — (iSs. to 


SS 




K19 


11-5 






KgO 


Berlin Porcelain Cups, which servo the purpose of small 
ailTcr.&c, glazed, page 98, No. 1.— 1 iniai diameter. 












Ktl 




3 
3 


L.— SUBLIMATION. 




Hard colourless Gennan Glass Tubes, free from lead, for 














LI 


With bulb, same as figure 1, page 101, 






Lfi 


Ditto, same as figure 6, . . . 




S 


L3 


— same as figure 7, . . . 




S 


L4 


— same as figure 3, but luger, . 
Straight, same as figure S.— See Ei to E 17, . 




5 


L5 






L6 


Poln^, same as ^re 5, 
Open at both enda.-See M 6. 




E 


L7 






M.— BLOWPIPE APPARATUS. 


Ml 


Japanned tin Blowpipe, with moveable brass pipe and 
brass noiile, page 110, .... 

Japamied tin Bfowplpe Lamp, with cap and supports for 
the fingers, page 113, ..... 

Rod and Poot tor the Lamp, polished black wood, 

A Burner for Gas, costs tTie same price as the lamp, 








1 




Me 


1 


6 


M3 




6 


M4 








Is, ed.— See C. 30 and page 114, 






M6 


Steel Tongs tor dressing tlto lamp wick, . . 1 




M6 


Glass Tubes, open at both ends, 6 Inches long, one. 
eighth to i inch wide, hard Gennui glass, free fiom 






lead, page Kt, . perA>*m, I 


8 



M15 

Mie 

Ml7 



MSO 

Mei 

M83 

MS5 



MEQ 

M30 



MSI 
M3S 

MS3 
M34 



Tube Veuels of Hard Glua, 6 nt U inch long, /o)- 
Ditto, eori|incbbi2inclieiloDe, „ 

— 6 of ij inches long, „ 

Chu-c(«], IE prepared plates, ptge I!3, 

Charcoal Borer, to prepare charcoal for Bupporting 

agnyi before the Mowpipa, tin plate, page 113, 
Charcoal Holder, tin piste, page 1£3-1, liepalr. 

Platinum Tonga, French psttem, with iteel blades and 

pl&tinumpoints, best quality, page li4, 
Platinum Foil, In slips of S inch by 1 inch, page ISS, 
two dipt at Sd. 
Platinum Wires, S inches long, pace 196, 3 pieces at 8d. 
Brass Wire for the detection of dilorlne, page IGS, 

3 Square BotUea, with plated topa, roTlKm,»ada, and 
microcosmic salt, ..... 

4 Booka of Utinua, turmeric, brazil, and lead teat p^wr, 
3 Rolls of Tin foil, for reductions, page ITS, . 
Square steel Anvil, page 1, . . . ■ 
Hammer for ditto, page 4, . . . . 

Agate Mortar and Pestle 

Box of Lucifer matches, .... 

Two amsll 1 Inch Porcelain CmsuIos, . 

A doaen !( inch Tubes, to hold the re-agents enumer- 
ated at page 1E7, ..... 
Albata Spatula and Spoon for mixing powders and lift- 

Three-Nusxe File to cut glass tubes, . '. 

A pair ofjapanned tin Boxes suitably divided to hold all 
the preceding articles, as described al page 867, 

Price of the foregoing Blowpipe Apparatus, complete, 
comprehending M 1 to M SS, 

The same Articles and Boxes, supplied with the fal- 
lowing Fluxes and Re-agents in a state of purity , 
Borax, Fluorspar, 

Soda, 
Microcosmic Salt 



Bleulphat'e of Potash, 
Gypsum, ' 



Oxalate of Nickel', 
Metallic Lead, 
Bone Ashes, 



thefo 
Steel Toiun, I Hammer, 

Platinum Tongs, Agate mortar. 

Anvil, j Three square File. 

The same set of Hlowpipe Apparatus as M 2B, with the 
substitution of a lamp with a screw for travelling 

Blowpipe Lamp with a screw for IraTelling, 

Berlin Forceldn Cup, one-third inch diameter, vi. . 

handle and cover, lor the Ignition of decrepitating 

substances, .... 
Berlin Porcelain Bottle for solution of cobalt. 



APPABATUS. 



Hard Oennm Glasi Retorts, stopperad :- 
1 oz. cap&city. 
Ditto, S 01. 



NU 
N15 

Nie 
nn 

H IB 

M19 



N.— DISTILLATON. 

ird German Glasa Retorts : — 
i oi. c&pacity, iiud« tVom tubes fDr_delicate ei 

Ditto, 8 02. . .™*'' 



Flint Glue HetortB, plain, 



Flint G1&99 Setorts, stoppered. 
8 oz. upicltf. 
Ditto, 4 OE. . 



Ditto, e 01 
Berlin Pore olain Retorts, glazed within, biBCuitwl 
Unstoppeted, No. ] " ' ' ' 



SCoppeied, 



-7 inches 
- 9 — 
_ 3_16 — 



— _ 3.— 16 — 

Stoneware Stiil, for theprepantionoFpurewiter, muri- 
atic acid and similar operations; ronsista of seve 
portions of the lamp funuce, page 2S3, 6 pieces. 

Tin plate Still, for the distillation of water, alcohol, 
Tolatile oils, one pint ctpaclt7, see paie S90, 

Flint Glass Becei>er, S oz. capacity, with long neck, 

Ditto, (same as B T), 8 oz. capacity, 

German glass receiver, or intermediate vessel, with two 

necks, 2, page8£S ..... 

CoNDEnsBBa : — 

Condenser, page 801, (lower figure), tin plate tube, 17 
by 2 inches, with leaden pipes for changing the water, 
japanned indde and outside, without cen^ tube, . 

Ditto, fitted with a glaied itoneware tube, 2S inches by 
i inch, page SOS, ..... 

Ditto, fitted with a glass tubs, slightly cooicU, SS Inch 
I .1. .1 _,.j 3 bordered, the lower 

page I9D, IS ioch japanned tin 



contracted, 
Condenser, small 

plate tube, without git 
Ditto, fitted with IB inch glasi 
Condenser, IS inch brass tul 



, I inch wide, without 



son uparatfoDs 

it be elemed so perftcMy as 

B consequently not so fit tor amdy. 



; Coo'^li: 



Bottle, wlthsplgot bole tt the aide for supplying 

Ditto, ' 1 gsllon, ' . ' . '. 

I Brass Stop Cock br either or tti«se bottles, 

0.— APPARATUS FOR GASES. 

a. For PitErABma Gases. 

I Gu Bottle, oval form, nith turned lip, long fiinnet, two 
' ubes, uid oioutobouc connector, p&ge 209, 

. leGisBottie, not fitted up, 

j Clark'sGBs Bottle, for testingiritlisulphiirBtted hydro- 
gen gu, uid for prepuing hydrogen, ctrbonic icid, 
and other gases, page S09, . . . , 
Wouirs's Bottle, with 2 neciu, stlt glazed stonewue, 
pfB/, page 811, 

i The Bsme, fitted with diagonal tube for (he preparation 
of bydrogen gas, carbonic acid gas, sulphuretted hy- 
drogen gas, &c.. 



Hard Glass Tube Retort, fitted to a delivering tube, for 
oiygen gaa, page 206, 
_ _ Ditto, larger size, a lii inch retort, 

O 9 Gas Deliiering Tube, narrow, page 806, 
OlO Ditto, wider, . , . . , . 

O 11 Bent Gas Delivering Tubes, page 938, . each 3d. to 

b, FoK COLLECTINQ AND ExAU[NINO GaSES. 

Stoneware Gas Holder, 1} gallon, with funnel, flexible 

pipe, and coupling screws, Co ' 
Ditto, 2 gallons, complete. 
Stoneware Pneumatic Trough, circular, 11 inches by 5 

inches, nith-bee liiva shelf, for Eupporting jars, and 

conveying the gas into them, page £14, !15, 
The Bee-hive Shelf, alone, page 815, . 
Three stoneware Trays for removing the jars ^m the 

Irougli when filled with gas, page 213, 
Set of four CyUndrical Gas Jars, see F 1 
Open Deflagrating Jar, for exhibiting the combustion 

of phosphorus in oxygen gas. Sic. 
Iron DeUigrating Spoon, 

Denting upon gases, 1 

O ei Japanned tin plate Pneumatic Trough, upon an impi 

ed constniclion, for jaia of 60 cublciJ inches, with 
sliding dielf and tray, page 217, 

Oae Pneumatic Trough for Tubes, in a single pi 



,. 


d. 


8 
8 




3 


6 

4 


3 

I 




1 
I 


a 


' 


s 

6 




6 


8 
10 


6 


8 


6 


8 


*i 


14 


ti 


4 




I 


6 



D,g,nz»-it.,Gl.>0^li: 



83 Berllo Forceliin Tnyt, for lifting tubes mied wi 
gues from the trough O S2, 1 indi diunetsr, aai 
O W Berlin Porcelwn Mercurial Trough, in « single pfec 



It Porcelain Tul 
■tuices Euhjecled ti 
page 887;— 

Hilf Inch wide, S inches long, 
_ 13 — 



JtiS 



wide, IS 



I Porcelain ^r»s to contain substances placed in such 
tubes, pige 227, 3 or 4 inches long, . . ««A 

Hard Glass Tubas for the reduction of metals by igni- 
~n gises, page 226, IS inches long, with one bulb, 

i Tube to contain fused chloride of calcium for Drying 

Gases, page £21, 9 inches by 3 inch, . 
I Bell glass, with ground stopper, 6 inch by 2 inch, 
i Ditto, . . . 7 inch by 3 inch, 

i Cooper's Mercurial Receiver, 12 inch, page 219, 
' ""'0, graduated into cubical inches uid parts. 



P.— WEIGHING AND MEASURING. 
1 Apothecaries' Scales, with a set of weights from i graii 



Ditto, , 

i Graduated Glass Measure, 4 ounce, 
i IronB«amwithhomBcales,(GBnnan),!8.ed. to 
' Cubic Inch Bottle, for specific gravities, long neck, 
■ ^'"a, with perfortted stopper, . , 



Q.— GLASS BLOWING. 

Glass TosBi, in lengCha of thres feet. 
The Nos. express the sizes 3e«cribeil on page 215. 
Hard aerman Glaii : — 

Nos. I, 2, 3 snd 4, per yard, 



;oIS, 



per lb.. 





•i 


10 
4 




2 




5 




S 








, 




I 








2 




4 




e 


6 


^ 




2 








1 


a 




a 

10 


6 












4 
1 






s 



I, Google 



308 OEIFFD.'. CE..1CAI. APPARATI... | 








d. 


<!U 


In one piece, uid bellows to tupply air ; Att«d on & 
tnme with treullB, spring, tlr pipes, uid noizlea, u 














descrihsd «t p»ge 239, but without tshle, 






n 


The double Stonewu-e Cistern, Iput, 






Glass Blower's Lsntp, complete, tin pl&te. 








Ditto, superior, titer Danger'* pBttoni, with bood to 

cmdnuw th« smoke, tin pUle, . ■ 






Q14 






R.— CORK BORING. 


R 1 


Three inch Hound File, without huidle, 




9 


R £ 


Sii Inch Roand File, without hudle, . 






R 3 


Six Inch Flat File, without hsndle, 




6 


R 4 


Dinger's Cork Borer, steel tube, with wooden hu>dle, 

l-gfth to l-third inch bora jsge «Ge, each, . 
Set of 6 Bnss Tube Cork Soren, one^th lo 4 Inch 












R 6 








Set of IS Krass Tube Cork Bonn, 6 Inches long, «>d 






R 6 








2, 8, 4,6, 6, 7,8, 10, 18, 14, la, »nd 80 siitBenth* of ui 








inch di«meter, pHe ies. 
Set of 7 BrsH Tube Cork Horgn, 6 Incbe* Ions, >nd 2, 






R. 7 










6 


S.— MISCELLANEOUS APPARATUS. 


a 1 


iS iquKB inches, 

Ditto, 100 squire inches, . . . . 




B 


S S 


1 


6 


3 3 


l.lhird inch wide. ' !^ ^"^ . ' ' . ^ 






8 4 


Ditto, 2 inches by t Inch, .... 
of light by the kctlon of hydrogen gas upon plstinum. 






8 5 












S 6 


Lucifer Mstches.'boi of one hundred, '. '. 




2 


8 7 










ai4, sealed bottle of 10 oz. 


3 




8 8 


-Shears for cutting sheet metsls, . pirpair 
Steel Tongs for lifting weights, trimming lam™, &c. , 
Ditto, witTi a apoon-sEapedhandle, for lilting fluies, 
Pyrope, Bohemian garnets, for couDterpoising, clean- 


2 




a 9 

SIO 




g 










ing bottles, &o,, per ounce, .... 




3 


8 IS 


Magnets, horse shoe form, with keeper, 

Berlin Porcelain Medicine Spoon, by means of which 






SIS 










a 


6 


S14 


Young's improved Voltaic Bsltery for the decomposi- 
tion of water and of saline solutions, for the combus- 














tion of metals, and the production of ele«tn>-mag- 








netic phenomena, in a stoneware trough. 


eo 




S16 


Caoutchouc Flexible Tube, l.thtrd inch wide, per foot, 






S16 


— — l-hilf — — 






S17 


_ _ On. - - 







orippin'b chemical apparatus. 


309 


ESTIMATES 




SETS OF CHEMICAL APPARATUS, | 


Ol-' VARIOUS EXTENT, 




SELBCTBD moil THE PORBOOINO CATALOOHB. 








^oS.(^=-r^^™<u.. 




The Ertlmttea present wh»t iqipattr to u» to be drticles 


of most 


eeneiBl use. We wish il, howerer, to be undergtnml, that we a 


e ready. 


in eiery cue, to vtjy the soleclion iccordliig to the instruct ions which | 


we miy receire from the purchaser, so thai no penon need take d 
of ipparalus already in his potsesslon, nor be deprived of article 
mif wiBh to have, although not quoted in the ItBtimates. We 


plicatet 


that he 




take the liberty to request that every order for one of the follon 


ngSBis 


»i8he> to have omitted, or of what he would like to have in ad 


urchaser 


ditlon to 


the articles embraced in the Kstlmate. 






Set I.— £1 Is. 








For Shall Phbpabations, Elbmehtabx 








Testihg, &■;. 




d. 


A 8 


Berlin Porcelain PesOe and Mortw, 


i 




B 8,6 


T»D Glass Solution Plaski, 


I 


i 


CBl 


Lamp Furnace, ..... 


3 




D i 


Tube Holder, 


1 




^Uiifiii 


ixeitTubeg, twoofeach. 


£ 


8 


eSo ' 


Two Conical Test GlaiSBB, 




ID 


EE5 


Small Tube Frame, 




6 


E 87,88,89 


Three Glass Stirrers, . . . . 




6 


ES^37 


T»D Teat Books, 




S 


E«,«,48 






3 


E« 


Test Spoon and Spltute, 
SetofiCyllndricalJars, 
FilterlngFunnel, 




a 


F15 


8 




G 3 
G 9 




6 


GI3 


100 Circular Fillera, ■ '. 




7 


H 3 


Stone Washing BMtle, . 




6 


I I 


Porcelain Capsule 




6 


I 19,81,83 


Three Stoneware Capsules, 






K 3 


Beriin Porcelain CruHUe, 




8 


K81 


Berlin Porcelain Cup, . 




3 


M I 


Japanned Blowpipe, 


1 




N 7 


Flint Glass Retort, . . . . 




6 


6 








9 


Three feet of Gas DeliTerinf Tube, 




6 


R 5 


Sinall Cork Borer, . . . . 

Sbt il— £1 iB. 
For ExpBBiwEimNo upon Gases. 




8 


N 8 


Glass Retort, * ounce, . 




9 


1 


Qui Bottle fitted for use. 


3 


e 



o.,glO 



I CHXUICAL APPARATITB. 



CSS 
C38 
D 1 

D 8 



E34 

B3S-39 
E 40--41! 
E 46 
P 10 
G23 
B 1 
H 7 



N3B.M 
O 1 
O 8 



St<menre Gu Battle, with bent Hack, 
Oiygen Gu Retort, wttfa tube, . 
Gti Delivering Tube, 3 feet, 
Appmtiu for Collecting Gasei, . 

S«T III.— £2 2b. 
Completewt of ArpABATce for Ahaltsii bj the 
BLOwriri, 

SbtIV.— £12 12s. 
Cootklning > complete set of AmaATtia tor Els. 

MDITAKI EXTKBIMIHTB on GaSES J for DkHON- 

•TUTiNO the PaoriBTiES of the Principal 
Chbhical ScBBtANciai for LigaiD TisTlNQi 
tai for Blowfipb Akaltsib. 
Two BerliD Porcelain Mortui, . 
SsTsn Solution Fluki, uwrted. 
Two Boiling Tubes, 
Two Poreelsln OigeaUn, 
Lunp Furnace, 18 utidei, 
Ltne Spirit Lunp, 
Gu Light Fittings, 
Trluigle Retort Stuid, 
MeUtllc Tobe Holder, 
Set of III Blocks of Wood, 
Univerwl Support, four bnutchei. 
Set of Supports for the Lirie Lamp, Ac, 
Assortment of Test Tubes, 3 to 6 incbea, 
Eight Clark's Test Gluses, with Up, 
Eight Conicsi Test Glssses, «ith spreading edge, 
Tube Rack, B holes, with stoneware pegs. 
Stock Tube Rack, 36 pegs, 
TwelTe (Hass Stirrers, 3 inch. 
Three Stirrers, two each, 6 and 9 inch. 
Two Dropping Tubes, 
Twelve Test Books assarted, 
Six Precipitating Bars, . 
Porcelain Spoon for Acids, 

Set of nine Beaker Glasses In ■ box, 

Set of Filtering Apparatus, six sizes, 

Berzellus's Washing Bottle, 

Ditto, for hot water, with handle. 

Eight Berlin Poicelain Capsules, E| to G Inches, 

Twelve Stonewsre Capsules, H to 10 Inches, 

liloneware Deep Basin, 6 Inch, 

Three Berlin Capsules, with handle 

Four Porcelain Crucibles, assorted, 

Nestoffive Hessian Crucibles, 

Two Porcelain Cups, 

Kowpipe Apparatus, 

Two Flint Glass Retorts, 

Small Hard Glass Retort, 

Condenser, with glass tuba, 

Condenser for small operations. 

Quart Stone Bottle, with stop cock, for water, . 

Gas Bottle, Htted with tubei. 

Ditto, not fitted. 



; Cookie 





e.™-«OH««,C*LAPPA^TUS. 


311 1 


O 3 


Oirk's Gm Bottle, 


3 


d. 


O 4 




1 




O 6 


Ston«w&re Gu Bottle, bent neck, 






O 8 


Tube Helort for oiygen gns. 






O 9 


Six feet of Gu Delivering Tube, 






O20 


Gix Appantus, complete. 
Stone Trough for mercury. 


U 


P' 


OSZ 




083 


Two Berlin Trays, for Gm tubes. 




3 


31 


Tube for the Heduction of meWs, 




3 




Desiccating Tube, 




9 


03* 
P I 


Bell glus, nith ground stopper, 
Apothecuiea' S«d«s »nd Weights, 


1! 


6 


P 3 


Gr»du.ted Measure, 1 ounce. , 


1 




R 6 


Set of twelve Brass Cork Borers, 


3 




R 1,2.3 


SetofFiies, .... 


i 


3 


S 8 


SbtV. £10 lOa. 

The sun« u Sbt IV., nith the omission of tb 

Blowpipe Apparatus, M 29. 

Set VI.— £5 58. 




6 


AS, 9 


Two Berlin Porcelain Mottirs, . 


3 


6 


H 1. 3, 6, 8 


Four Solution Flasks, 


2 


5 


BU 


Boiling Tube, .... 




4 


BI9 


Porcelain Digester, 


I 




C 19 


Lamp Funiace, complete. 


S 


6 


cas 


Large Spirit Lamp 

Triangle Retort Stand, . . . . 
MetaHic Tube Holder 


12 




D 1 






n 8 


1 




D 9,2S 


Holder for the Spirit Lamp, 


4 


6 


Dia 


Sefstroem's Press Holder, 


3 


6 


D« 


Pan for working upon, .... 




6 


E 1.3,8 




8 


3 


E 11 


Eight ditto, large, . . . . 


2 




EKO 


Sii Conieat Test Glasses, 


2 


6 


ESS 


Frame for eigM Test Tubes, 


8 




EST 


Six Glass Stirrers, 3 inch. 




6 


E!8,S9 


Two Stirrers, each 6 and 9 inch. 




10 


E34 

E36to30 


S?Cf£L"i'S;,,- : ; : 




3 
8 


E40to4E 


Three Precipitating Bars, 




3 


E45 


Test Spoon and Spatula, .... 




6 


F 110 6 


Six Beaker Glasses, .... 




6 


GB5 


Small set ot Filtering Apparatus, 
Berzeliua's Washing Battle, 
Nest of four Porcelain Capsules, 




5 


H I 






I la 






1 3( 


Nest of six Stoneware Capsules, . 




g 


I 37 








K 1,3 


Two Porcelain Crucibles, 




6 


Ka),g| 


Two Porcelain Cups, .... 




6 


N 7 S 


Two Plain Glass Uetorts, 




3 


N80 


Condenser and Stoneware Tube, 




6 


O 8 


Gas Bottle, glass, oial, .... 
Woulfe's ^ttle, stoneUare, 8 necks, . 
Stoneware Gas Bottle, bent neck, 




4 


4 






6 






O 8 


Hard Glass Ketort for Oxygen Gas, 







Google 



I IS 

1 31 
K I 



Delivering Tube, 6 feet, 

lewiTB Gas Appantiu, 

Pii«iim&t!c Trougli for Tubes, 
Sm&ll Berlin Tmr for Tubes, 
Sereii Bra^ Cork Borers, 



Sbt VII.— £3 3b. 
This set includes m Selection from the Appar- 
atus for Ulovfipb Analvbu and for Expehi. 

SmsU l-oreeliiin Mortir, 
Three Solution Flasks, . 
Lamp Furnace, complete, 
Triangle Retort Hofder, 
Metallic Tube Holder, : 
Three Tubes, each id., lid., Sd., 
Frame for eight Teat Tubes, 
Three Conical Glasses on foot, 
Three Stirrers, 3 [ttch, 
One Stirrer, each B and 9 inch, . 
One Droppii^ Tube, plain. 



ippin* . 
Six Test UookB 
Three Precipitating Metals, 
Test Spoon and Spatula, 
Nest of four Beaker Glasses, 
Nest of four Glass Cylinders, 
Filtering Apparatus, 3 sizes. 



Porcelain B 



-e Basins 



Berlin Porcelain Ci 

Two Beriiti Porcelain Cups, 

Japanned Blowpipe, 

Blowpipe Lamp and Support, 

tjii Hard Glass open Tubes, 

Charcoal Borer and Holder, 

Platinum Foil um Wire, 

Brass Wire and Tin Foil, 

Small Porcelain Capsule, 1 inch. 

Glass Ueton,S ounce, 

Small Condenser and Tube, 

Woulfe's Bottle, stoneware, 

Stoneware Gas Bottle, with bent 

Oxygen Gas Retort, smijl size. 

Gas Delivering Tube, 3 feet. 

Stoneware Pneumatic Trough, 

Two Stoneware Travs, . 

Open Deflagrating Jar, . 

Iron DelUgraling Spoon, 

Apothecaries Scales and Weights, 

Graduated Ounce Measure, 

Trlanaulir File to cut Glass, 

Hound and Flat File, and set of four Cork Borers, 



SRIFFIN a CBBMICAt. APPARATQS. 

CHEMICAL PREPARATIONS. 

PURE RE-AGENTS, ETC. 
R. Gbittin and Co^ will hire rtidy for Sale, In > feu 






Complete JiiDr'men' of Chimical Re-aqknts, moatlj' preptred for tbeiD 
In Gennsn^, snd sil in k slate of the grealcti pvriig. They will also 
have ■ v&riety of Bsie Chemlcml Product!, uid such other Prep&ntions 
or Mineral Substances u ue requieite for the prosecution of ChemJcil 
Researches. Students or Teachers may be supplied with these Re- 
agents either in sets or single articles. The prices nill be moderate. 



Acetate of Soda. 
Alum, (Potaah) cryat. 

(Soda) ciyst. 
Amber Vamish. ' 

Ammonia, Carbonate, 
Muriate. 
Nitrate. 
Antimony, Metallic. 

Sul^uret (natiie). 
Rarium, Chloride. 
BaiTtel, Acetate. 

Carbonate, pcacipitatad. 
Caustic, cryst. 
Nitrate. 

Sulphite (natlTe). 
Bismuth, Metallic. 
Subnltrate. 



Rroniine. 
Cadmium, CarbonMe. 

MataUic. 

Sulphuret. 

Sulphate. 
Cakluiit, Chloride, cijst. 

Fluoride. 
Chlonte of Potash. 
Chloride of Lime. 
Chiemate of Potaslii yellow. 

Cobalt, Black Oiide. 
COTtper, RlaclE Oxide. 

Nitrate. 

Sulphate. 
Fomat* «f iSvda. 
Cell Nuta. 
Gold Lead 

ll^^of Potaaeium. 

Iodine. 

Inm, Sulphuret. 

Sulphate. 
Persulphate. 
Lead, Acetate. 
Cacbonaie. 

Nitrate. 



Lime, Carbonate. Nitrate. 

Caustic. 
Litmus. 

Magnesia, Carbonate. Sulphate. 
Manganese, Ferealde. 
Mercuiy, Cyanide. 

Chloride (calomel). 

Metallic. 

Nitrate. 

Perchlorida (cor, sub.}. 

Red Oxide, preclp. 
. _..nic8»lt. 
Nickel. MetaUic. 
Oxalate of Amnumia. 
Oxalic Acia. 
FallBdium, Metallic. 
Platinum, spongy. 
Phosphate of Soda. 
Phosphoric Acid, fuiwd. 
Phosphi 



Carbonate puriiled. DD.veiypu 
Caustic, In MIcka. Do. tc 
pure. Nitnte. Sulphate. 
Potassium, Metallic. 

Sulphoi^aiiide. 
Sulphuret. 
t^msiata of Potaib. yellow. 

Silicate of Potash (basic). 
Silier, Nitrate, ciyat. 
Soda, Bicaibmate. 



Sulphate. 
Sodium, Metallic. 
Starch. 

itian, CailHuiata. Nit 

itium, Chloride. 
Succinic Acid. 
Succinate of Ammonia. 

I of Soda. 
Tartaric Acid. 
Tin, Protachlorlde, ciysl. 

Uranium, YbUow Ozida. 
Zinc, Metallic granulated. 
SulphatI ""-"- '^' 



hate. White Oxide. 



OKIFFIN e CABINXTB OP MINAA.LB. 



'^ MINERALS AND ROCKS, 

For the Use of Students of Mineralogy and Geology. 

Collections of Minerkb uid Rwks, idipted either for private stu%, 
or for eihlbition in a clus ; comprising spBcimens fttim ill puts ' 
the world, tteab, neitly cut, well usorted, uid scientiGctlly arruigt 
The specimenB eihibit In all cues with distinctness the chiTBcten 
whereby Minenls are disciimlnaCed: while the selection is such w 
to present even in the smallest collections those Minerals which an 
of the greatest importance. The whole are displayed in tiays, with 
diiisions, enclosed in stioii|; boxes of millboard, neatly ornamented; 
uid accurate Catalogues, expressing the name and locality of ereiy 
Specimen, accompany all the Collections. 

No. 1. Ghiffin'b MiNntAL Cabinet, comprising 60 Gpeclmens of 
Minerals, and GO specimens of Rocks — size, two square inches, with 16 
models orCiTStals; affording the means ot forming a practical acquaint- 
ance with the kindred sciences of Mineralogy, Geology, and Ci7Stallo- 
graphy.— .Siie of the Cabinet, 18 by 10 inches, and 8 inches deep. Price, 
(including a copy of the descriptive catalogue named below,] fSs. 

This Cabinet is intended for persons who may be reading tllement- 
aiy Works on Mineralogy, or sltending Popular Lectures on that 
Science. Comprehending well characterised Specimens ot one-Iburth 
of all the Minerals now known to eiist, and one-hslf of all that are of 
any Scienlitic or Commercial importance — it is adapted to alTord much 
useful intbrmatlou as to the exact appearance and properties of the 
indiiidual Minerals which it contains, and lo give incidentally a Tei7 
clear idea of the objects of Mineralogical Science in general. At the 
same time, it Is presented in so convenient a form, and at so moderate 
a price, as to brinE it within the reach of all by whom a knowledge of 
the riches of the Minertil Kingdom is held desirable, but who have not 
the opportunity of personally examining the Specimens of Minerals 
placed In Public Museums. 

OOTLINKI OF MlNKBALOOT, GeoUJOT, and CBTSTAULOOIlAPHt, CflDI- 

prialnif some account of the characters by which Minerals and Rocks 
are distiDguishsd — explanations of Mineralogical nomenclature — prin- 
ciple* of Mineralogical and Geological cl>ssincation-«t Outline of the 
Science ot Crystallography — and an exact description of the hundred 
Rocks and Minerals contained in " Gbiffin'b MimeHal Cabinbt." 
I&QO, •«Kd and gill, price Is. 

No. 11. Griffin's Stddsnts' Cabinit of Minerals, 60 specimens, 
small siie, arranged in a neat Cabinet, 10 by 6 inches. Price lis. ; or 
with the Book of Descriptions, 13s. 

No. III. Griffin's Stddentb' Cabinet of Rocib, GO specimens, 
unifbrm with the preceding Collection, Price 10s. oi with the Boolt of 
Descriptims, lis. 

""\e Specimens In these two Cabinets are of the same nature as those 
_... lined in No. 1., and the descriptive " Obtlinsb of MinbEaLOOV" 
can therefore be used with either of them, as it contains an exact de- 
scription of every substance in both Cabinets. By this arrangement it 
is rendered possible for a titudeut to acquire the means of lorming a 
practical acquaintance with the leading features of Geology, Mlneral- 



; Coo'^li: 



100 choice Specimens of Simple Minerals, one tquu-e inch ia -siz 
ranged in a C^Inet containing a single tray. Siia IS by U> ii 
Price Sl9. ^ ., 

This Cabinet is particularly adapted for Ladies conunMiring the 
study of Mineralogy, or attending Popular Lectures on tbat Science. 
The Specimens are accompanied by a Printed Catalogue, showing theii 
names and localities. 

The LADiia' Miniatorb Musedw may also be had in an elegant 
KoKHood Olait Can, exhibiting the whole Hundred Specimens at — 
view, and forming » useful Drawing-Room Ornament, Price 3ls. 
No. V. GBirrm's Collection of Minerals foh Ekahinai 



Classes, ana aosptea lo uintreiit muuvd vi An^yma dv 
or the Blowpipe. Biie of the Cabinet 10 by 7 inches. 

This Cabinet presents, in s convenient Tonn, and st a moderste price _ 
collection of the Minerals which it is most useful for Students of Che- 
mistry and Mineniogy to begin their studies with. The Species selected 
TB suiji as produce on analysis the greatest variety of remarliBble phe- 
omena, and thus afTord the Experimenter both amusement In the 
iversity, and instruction In the number of the mineral characteristics 
developed in the course of his operations. The chief ores of the most 
- - netals are included. The quantity given dI each Mineral is 
r several Analyses, as well gtianliialler as jaaUiatine i and 
the greatest reliance may be placed on the genuineness of the speci- 
mens. A series of experiments, performed with care < " ' ' 



of this Cabinet, will qualify the Student Co undertake a successful e 

... ir well-known Mineral that maybe presented to 

. The names of the Minerals comprised In this Ciritectlon fte given 



itlon of any oth< 
The names of tl 
; page 188 of " Chkkical Bkc 



tiays, contained in a box. Price 

No. VII. GBiFriN's Hineralooical Cabinet.— One hundred and 
fifty Minerals, including muiy of the rarer species. — Size two square 
■nches of surflice, in five trays, contained in a box. Price £S, I^ 6d. 

No. VIII. Griffin's Geological Cabinet.— One hundred Larger 
Specimens of H ocks.— Size four square inches of sorftce, in four trays, 
contained in a box. Price 4Sa. 

No. IX. Griffin's Geological Cabikbt One hundred and fifty 

Kocks,— Site four inches square of soiftca, in five trays, contained In 
1 box. Price £3, 13s. 6d. 

More Extensive Collections of MiukbalS and Rocis, oUAatU CaH- 
ncfi, from four gulne 



fifty guinea 
i. X. A Collection of 300 Hinkrals —Size four square Inches. 
s £10, lOs. Pasteboard trays, with blue edges, to hold Minerals of 
uiis sire, 3 Inches long, EJ inches wide, i inch deep, per )00, 9s. 
No. X.I. A Collection of SCO Rocia. — Size nine square Inches. 



Price £10, lOs.^ PistebMrd trays, wjth blue edges, to hold^MiinerBls of 

^ze"''^ , 

Price £8, 16s. Pasteboard trays, with blue edges, to hold Hocks of this 
slie, SJ inches long, 3 inches wide, Jinch deep, per 100, lOs. 

No. XII. A Collection of 500 Roc eh. — Siia four square inches. 
Price £15. 

No. XIII. GRirnN'a Cabinet of Organic Remains One Hoi 

di«d Specimens, in very fine condition, size when In mssses of Rock, 
four square Inches of surDuie, in four trays, contained In ■ box, with a 
Manuscript Catalogue. Price £5 lOa. 

No. XlV.— Griffin's Cabinet of Roces and Obqanic Rehaiks.— 
One Hundred and Fifty Specimens, size four square inches of surface, 
in five trays, contained in r ■— '•-- -" ■'- " 



316 oRirriN'g cabimbts o 



In tbj« Cabinet, the Rocka ire irruiged in the order of their ntpei- 

KBltion in the earth, uid after euh series follow the Organic Remuni 
, nhlch the Rocks are most distinctl7 chancterised. 

No. XV. GHirriN'a Collkction of Metallic Obis —One Hun. 
Ired and Twent; Specimens, size six equue inches. Price ^lO 10s. 

An Encellent Collection for >. Meehuiic's Institution, or for a Lee- 
urer on the Applicaliona of Chemistry to the Arts. 

Models orCnvsTALs for Students and Toachers of Cijstillogr^y, 
'err neatly made of pasteboard, and varnished. Price 16s. the set of !c3 
'(Uieties, and eOs. the set of 100, including 77 vtrieties of secenduf 

ROSEWOOD CABINET for MINERALS, containing SO dra» .__, 
*ith folding doors and lock, iiandsomely finished and French p^rilshed ; 

eiiK: — 3 feet 3 inches high, 3feetwide, I foot 7 inches deep. 
Adapted to conUin the Collection of AIlnenlB No. X, and the Collet' 
tion of Rocka No. XI. Priee of the Cabinet, £]0; or, with thtei 
CollMtions uid Trays, TaiBtv GmNua.— 

BRONGNIART'S CHART OF GEOLOGY. 

HandMneiy Engrated on Copper, size SSbygl inches, printed on i 
sheet of Atlas Draiving Paper, and Coloured. 

THEOBEticjL Table o[ the most general Eubopean Succession and 
Disposition of the Stbata and Rocks uhlch compose the Cedst of 
the EA&TH;ar, a Graph ical Exposition of theSscTiON of tbeEAKTH, 
~ r as It is non knownj with Signs indicating the Minerals, Metals, 
and Organic Remains which compose or cl^cBcterise the different 
Strata. By Alex. BKONSNiiRT, Professor of Mineralogy " "■- " 
leum of Natural ^Histoiy of Paris. 

The Catalogue of Kocks and Formations is carofully tnmslated, uid 
enlarged by many British Examples and Syj ' 

Price of the Table:— On a Sheet, Coloured, Sa. ; in i Case, for 
Travellers, Ts.; Mounted on HoUers, and Varnished, lOe. 6d. ' 
Roisevioiij Fictuje Frame, French Polished, gilt Border, Sis. 

EDE'S PORTABLE LABORATORIES. 

R. B. Kde's Youth's Labohatoby; or. Chemical Amusement 
containing 40 Chemical Prepsmtions and Appropriate Appkntui fbr 
(he_ Performance of Experiments. Price 16s. 

iB's Chehical Pobtable Labobatort, containing abore 90 salect 
and useful Tests, Re-agents, u>d appropriate Acptratus, A>T ■ Coarse 
of instructive tutd entertaining Eiperimenta. Price £1 lis. ed. 

The SAMS Lahobatoki, fitted up «ith Slopptrad Bottles, Ghui ^rit 
Ump, Lock and Key, and French Polished. Price £S Ss, 

Eue's Cuekical Cabinet, or Auateob'b Laboratotiy ; cimatttiiig 
of more thui 130 select Chemical Preparations and newly-invflntad Ap- 
paratus; for performing refined Eiper' '- '■-■'■ "''-' .— .i™ — j 

research, in nay Uratring Hoom, with 

The SAME Cabinet b fitted up with 

a superior uid more substantial muu_-., . , 

handtas, comers, &c., suitable for travelling. Price £7 Ids. 

Ede's Mineealogical Box, or Pockkt BLomPB Affabat 
neat japanned tin case, only 7^ inches long, and 8^ inetm broad. 



INDEX. 



Acetic nti^ths, El. 

Acids detected, 46, 4T, 105, 134. 

Acids, mtntlon, 69. 

Acids, minenl, detected, 1T4. 

Adapter, 192. 

Affinitjr, xiiT. 

Ait, hot, current, 87. 

Ante mortar, 3. 

Alc&lf es detected, 46, IDS, IS6, 1ST, 

171, 
Alcaliea, Low diitlnguished from 

euths, ISO. 
Alcohol, M fuel, IT. 

still for, 1ST, ego. 

Alembic, 103 

Alumina detected, 144, 16S, 174, 

I7B~1S1. 
Ammonit, carbonate sublimed, 107. 
Ammonia gas collected, 8!4. 
Ammonlaial salts detected, 

165. 






ratus I 



ipporW 



Basin holder, 44, 2H5, £66. 



Bath, sand, 86, £8, 30, 260. 
water, 89, 2^1, 89S. 
saline, 90. 
Beaker glasses, Qj. 
Bellows blowpipe, 339. 
Tending of alass, 858. 
lenzoic acid sublimed, 106. 
lerlin Porcelain: — 
Basins, 85. 
Capsulee, 85. 

with handle, 66. 
Crucibles, 98, 99, £86. 
Cups, 96. 



Auvil for blowpipe ezperii 

Anvil to use in working metals, £73. 

Apotfaecariea^ weight, f'^' 



Pneumatic trough, SIT. 

Retorts, 194. 

Trays, 8B7. 

Tubes, 287. 

Water hath, 89. 
Bismuth detected, 145, 147, 15S, 

157,168, ITl.lTB— 181. 
Bisulphate of potash, use, 1S7, 139. 



Argand oil lamp, £1. 

spirit lamp, 19, £81. 
gas light, 879. 
Arsenic, add, detected, 137. 

metallic, detected, 136, 

1*0, 164, 165, 167. 
sulphuietf detected, 135. 
white oxide, del 
137, 140, 156, 1( 
^eniurets roasted, ITD. 



, detected. 



flfiU witlig>a,£13,216. 



boxes for Huxea.lST, 128, 

287. 
hoi for apparatus, 13(r, 



'..".ooglc 



lowtorep^r, 116. 

inner a«me, 120, ISA. 

jet, or noiile, 111, IIG. 

lunp, ll£, Ses 

luup nipport, lie, S8B. 

oiId>tliigflune,llH,IS6. 

outer Sune, 120, lS6. 

leduciBsflune, 119,106. 

steady &me, 115. 

Eupports fbr U81VI, ISO. 

UUe, 239. 

tongs, 124. 

uaa or, 2, 107, E38. 

irireE, I £6. 

work tiAl«, IS9. 
Boiling, E6, 27. 

In tulxiB, 16. 
Bone Ariiea, use, 1S7, 14a 



Bottles for re-ngeuta, S6, SS. 

■tonawKre, 811. 

Htoppen loosened, S7I . 

to prepu-e nses, 206, 211. 
Brus wire, IBS. 
BrBzll leat paper, lOfi, 135, 139. 
Bromstea detected, 147, I5S. 
Bromides detected, 139, IS^, 15S. 
Bulbs, ilasa, blonn, £54. 
Bulb tubes for solution, 7. 

sublimition,IM,100. 

Cubage test, «!. 

Cadmium detfcHi'd. 136. Ml, 145, 

158, 167. 171, I7:<— 181. 
Calomel detected, 137. I3S, 110. 

Bubllmed, 107. 
Camphor, sublimed, lOT. 
Caoutchouc sheets, prepared, £70. 
use, 239. 
tubes, 925, 969. 



porcelain, 13, BS. 

stoneware, ESS. 

Carbonic actd gas apparatus, 209. 

Carbonaceous Substances detected, 

157. 
Cementlnf , 192, 87a 
Gerium detected, »5, 166, 1S7, 

174, 178—181. 
Changes of colour on Ignition, liT. 
Charcoal borer, 181 
holder, IS4. 
supports, 1E2, 142. 
Charges, how to put Into glass ves- 
sels, 15, 106, 196. 



Charring, 101. 

Chaufler, 28. 

Chemical combination, cause of. 



Chemistry, its nature, objects, and 

Chimney to carry off lapours, B63. 
Chlorates detected, 147, 168. 
Chlorides detected, 148, 162, 155. 
Chlorine gas collected, SSa 
reduction by, S2eL 

Chromates detected, 147, 178 

181. 
Chromium detected, 144, 166, 167, 

168, 178—181. 
Cinnabar sublimed, 107. 

detected, 135, 138. 
Clarii'g filtering ring, 72. 
gas bottle, 209. 
test glass, 63. 
experiments, iii, 63, 93, 106. 
Cleansing, 261, ^6. 
Closing of tubes, 263. 
Cobalt detected, 112, 146, 166, 169, 
172, 178—181. 
nitrate, use, 127. I6S. 
Collecting of gases, SI 1 , 
Colouredl>ea<&, 17K— 181. 
flames, 143. 
tests, 47. 
Compound bodies, xxiii. 

distillation, 289. 
Condensation In distillation, 1S6, 



Connectors, caoutchouc, 2£5. 
Copper blowpipe wire, 186. 

detected, 148, 161, 1S(), 

169, 178, 178-181. 
nitrate, prepared, 16. 
Dilde reduced, 141, 146. 
Cork borer, brass, 868. 

Danger's, 266. 

Mohr's, 267. 

boring and cutting, 866. 

press, use. 

handle for tubes, 35. 

for watch gUsies, 35, 

CorroilTe sublimate detected, 137, 

138, 14a 
Crack in glass conducted, 849. 
Crucibles, cylindrical, porcelain. 



Cniciblea, bl&ck lead, 100. 
HeaslBti, 99. 
hoir heited, 106. 
jukat fbr, SO, ^. 
opcntiona with 
conducted, tOI. 



plUini 



1,97. 



tongs, 100. 
Crystallisation, 1,91. 

by fusion, 91, 93. 
ulutlOD, 91. 
sublimation, 93, 



promoted, 9i, 95. 

water of, 91, 100. 

use of, 91, 9S. 
Ciyatals, to form large, 94. 

t^oloured, M. 
Cui>8llatiDii, SB, 143. 
Cup, poTcelsIn, 13, 96, 101. 
Cup, pUtinmn, 14, 80. 

perforated, for lamp fur- 

Twce,M. 
to lengthen the lamp fur- 



Decoction, 16. 
Decompositlan, xxllt. 
Decrepitation, 101, I3S. 
Deflagrating jar, 216. 

spoon, 216. 
DefltgraUon, 139, 147. 

tried, 141. 
Demonstrative experiments, i: 
Desiccating tubes, 2E4. 
Desulphuration, 170. 
Determinative experiments, xi 
Diamond cement, £76. 
DlftbrentHirtaofiiibsUnces, » 
Digestion, IS. 

in tubes, SB. 



Lviii, 2, 183, see. 

i^Hnpound, !29. 
faclfitMed, 904. 
In flasks, 194. 

metalllG stills, IBl. 

retorts, 198. 

Uoneware still, ESS 



ordinary, 184. 
>ver flasks, 86. 
>verretarts,96,196,361, 






9,90. 



Earths detected. 156, ie7. 
Edges Dt glass, how mad off, SSO. 
Education, why chemistry should 

form a stated branch of, xvii. 
EdutcoiatioD, I, 79. 
Edulconttor, 79. 
Elastic tubes, S69. 
ElemenUiT Etodies, ixili. 
Esprila, m. 

Evaporation, xviU, 1, S7, 84, SSS. 
by salt bath, 90. 

water hath, 89. 
in close vessels, KM. 
the largo way. HO. 

to dryness, 67. 
vessels for, HS. 
Evaporating cqisules, stoneivare. 



Experimenting, i 
Experiments, oil 

Extract, 1& 



platinum, IS, 14, OB. 
suiitaetsgut, SO. 
- ir, lix. 

nt classes of. 



Fat lute, £74. 

Files to cut cork, we. 

glass, 84H. 

mstai, sra 

Ftltering ring, 78. 

Filtering paper, varieties of, 7 

apparatus, 66. 
Piltersr-thelr materisl, 64. 

ashes, estimated, 79. 

circular, 76. 

dried, OH. 



Filten, Mded, plain, 64. 
ribbed, 70. 
held without funnels, 71 
how to cut, 73. 
proper jpwer, 76, 
(izes, 74, TO. 
weifbed, 6& 
FiltratioD, iTiii, I, 63, SS5. 
preautions, 67. 



coloured, 148. 

hottest urt oi 
intcrmittiiig, 1 
OxidMing, nu. 



'iiV,S4E. 



ng, 118, ISe. 

Fluues, coloured, 148. 
Flisks, bordered, SSL 

cut asunder, 149, 

flintglus, 1I,1E. 
hu^ eluB, 11, 18. 
how chsTged, 15. 
porceUiu, 13. 



tariis&tion, 9i 



Bupparled, !6, 36. 
UEMl BS retorts, 191. 
Flat glass, use in solution, 14. 
filtntioa, TS. 
for stirrers, 48. 
in testing, 6' 
ciTstsllisi 
Florence fluk, 10, a~ 
Florentinii receiver, 191. 
Fluids decanted, 68, 69, 

separated, 191. 
Fluorides detected, 134, 139, 163. 
Fluorspar, use, 1£T, 109. 

detected, iM, 169. 
Flux, black, I0£. 
crude, lOS. 
white, 102. 
Fluxes, blowpipe, 12G. 

boxes for, 127, 130, 867. 
Formate of soda, use, 187, 140. 
French decimal weights, £30. 
Fuel, advantages of ditTcreut kind! 

84. 
Funnels, safety, S31. 

best shape, 64. 

fur filtration, 64. 



Funnel bolder, (br large funnels, 
£83. 
earthen ware, 67. 



blast, as. 

chaulfer, 1!8. 

cupellatlon, 3£. 

limp, e4. 880. 

Luhme'i, 89. 

portable, 89. 

reverberator?, S8. 

Sefstroem's, 33. 

wind, 30. 
FusibUilr tried. 141. 

of the metals, 14!. 
Fusion with soda, 164. 
Fusion, iviii. lOS. 



delivering tubes, t08. 
balder, sttmeware, 815. _ 
jars. filS, 813. " 

receiver, SOT, 812, 2iO. 
Coiimer's, SIH. 
trays for, 213. 
trough, water, 8I£, £15, 9l6. 
mercury, g 17, if 18. 
Gases, production. 8, KOfi. 207. 
reduction by, 285. 
balloons mied, 216. 
bladders filled, 813, 216. 
collected oyet water, 811, 
880,821. 

mercuIT, 217,218. 

in a gasholder, 214. 

collected by displacement, 



measuring, 8£6. 
solution of, 227. 
transferred. 81S, 216. 
weigUng, 22S. 
3 light apparatus, 23, 279 

for the blowpipe, lU 
Glass, written on, 276. 
Iilonn, 838, 2 >4. 
bored, 200. 
bulbs blown. 264. 
cutting , 248, 860, 270. 
cutters, 249. 
filed into shape, 230. 



I, irliidiiif , ETI 
pUtM,t7l. 
nnwd, SSO. 
lod), 4e. 



■tq>pBn, tro. 

S round, £71* 
HHened, «»■ 



blown IntobullH, !S4. 
' nei. 16, lOS. 



cbtrged. ll 
chaEed,t!! 



cleued. 104, 344. 
elDied,S5S. 
rmtncted, 2sa 
cut, 848. 
dnwn Hit, ten. 
dritd, 00, 106, 844 
for wdutton, 8, 10. 
teiubllnutloii, 104. 
lie»t^S4S. 
Jollied, 8ii«. 
piarced, 857. 



vtBMlf dried, SO. 
GIlH blower^i table, 839. 
lunp. 840 
Glucliw datected, 144, 171 173— 

181. 
Gold delected, 148, 166, 178, 176. 
Gnouletlrai, 6. 
Crete, Ainiace. 88- SI. 
Grinding of glue, 870. 
Gypeum, use, IWI, ISO. 



r.4. 

for capcnlei, 881 
Buidlei for tuUi, 3S, 43. 
Hatt, uplIcMlao, 1, 17, 870. 
Heat, lourcei ot, 17. 
Heniui erucililet. BA 
Udei Irared In gl*M, iW. 
Bood to c$ny ofl'T4paun, 863. 
Hot dr. cnirent, 87. 
■ llotpUtea,8S. 
Hrdrogen gM appumlua, 800. 



Hypoiiilphitea detected, 136. 
IgnltioaJn glui lubei, 108,106, 
138, 160. 



IX. 321 

Ignition, xTill. t, 81. 06. 898. 
Indian rubber tubei, !S6, 8tl0. 
Indigo lubllmed, 107. 
Inriuion, 16. 

Ink to write upon gtue, 876. 
Innlubllity, XTiii. 6, 
Intennittiog flune, I7B. 
Intumescence, 141, 147. 
I odetes detected, 147, 16a 
lodidu detected, 139, 163; US, 168. 
Iodine lublimed. 107. 
Iridium detected, 148. 166. 
Iron detected. 143. 14S, lie, 167, 

178, 178—181. 
Iron ntort, 206. 

JeekeU for ernciUee, 80, 97. 

Jin Im getee, 63, f IS. 

for dui eiperimenti, tO, 
for precfpItKtlon, 08, 63. 
for lolutlool, et, 63. 

Jet, Uoirpipe, 116,841. 



UbeUlng, it> nsceultv, 861.8. 

metliod of, 874. 
Ltbontorv, gmertl lilDti reip«et> 

Lunp fumece, 84, SSO. 
for oil, tin, 18. 

Arguid, 81. 
BerieliuB'*, 82. 
etonewire, 881. 
>iippart,883. 
for ipErit, glue, 17. 

^irauUr »l«k, 10, 



Sdl. 



84. 



bett oil fe 

- ,Ipe 



gu, iS, 879. 

glua blower'e, E4a 

■upported, 36, 44. 

*iclu prepared, 88. 
Lapiduy work, 871. 
Lavender water. 191. 
Lead detected. 146, 147, 164, 167, 

169, 178, 178—189. 
Lead granulated, use, 187, 143. 
Lead, phoepliate, detected, 147. 
Lead ailta reduced, 141. 
LeTigation, 8. 
Lime detected, 144, 16S, 174, 17S 



Liquida beiled in tube*, 0. 



C.ooglc 



MMBntiDD, 1& 

MuneaiB detected, li4, IM, 174, 

178—181. 
Mkfitetic inaUli, ITS. 
Mmnuement of geaea, 80$. 
MuiguieM delMted, 146^ IBC, U7, 

169, 178—181. 
Muilpuliitlm, 1. 
Mktnaa, porcelsln, IS. 
Meuurlng, S, !S6. 
Meuuramant orgwwSjKS. 
Menttruum, 0. 

Mercurial trough, itoneirin, {18. 
porceUin, !17. 
tube recelTer, £18. 
Mercurial lalU redncad, 130, ISS, 

1S7, 138, IW. 1«. 
HercuiTi bromldei del«cted, 137. 
13S. 
cbloridM dstKted, 137, 

detected. 136. I3S, 147, 

185, 163, 178. 
iodldei detected,187, 139, 
red oxide, sublimed, 107. 
sulphuret, detected, 136, 

Metallic nlti redodble, IfiS. 

tube holder, 40. 
Hetili, Auible detected. I4S. 

fiiea Meeted, IG8. ITC 



toolB for woriLliic, 87!. 
Tol&tlle detected ISS, 13B, 



Mtnerele cut uid polished, £71. 
action with end*, 166. 
for eiperlment, 167, 173, 

fuiibilltT, 146. 14S; 
table of bitumeMeQl, 148. 
offwible, 168. 
infuilble, laa, 
puU7flirible,10T. 
Mineral acldi detected, 174. 

■lake, 4. 
Muffle, gS. 



MolTbdenuiD detected. 1«, ISS, 

ISS, 168, ITS, 17^-181. 
Mortan, Agate, 8, 16ft 

Apothecaries', 3. 

Berlin porcelain, & ITOL' 

SanitaetBgut, 3. 

Seipentine, 4. 

Steel, 4. 

Wedgewood'i^ 3. 



Ldeiuer,li77. 



cork-borer, £07. 
Muller, £. 

Muriatic acid. Instructions for 
porirving, !eO. 

gas collected, ££3 

NeutnaiU, 47. 
Neutrellaaticm. 46. 
Nickel detectMl, 142. 143, lfi6, 
ITS, 178— IBl. 
Olalate, uee, 1£7. 
Nitre, deflagrated, 133 

oae, lfi7, 177. 
Nitrates detected, 134, 139, 1^7. 

Odours produced before the blow. 

pipe, 1m, 160, I7a 
Ull as fuel, il, 118. 
best sort, St; 
oTvltiicd, diililled,era. 
Oil lamp, Berullua's, ££. 
bloin)ipe, 118. 
stoneVare,S8l. 
■mall tin, 1% 
tin, Argand, II. 
Oils, Tolatile, itm for, IPg, Wft 
O^anic bodies detected, i:>8. 

discriminated from inor- 
ganic, 183. 
matter Tolatilised, 101, 
ISBrlSS. 

Osmium detected, 137, 148, 155. 
Oxalic acid detected, ISG. 
Oxalates detected, 135^ isa 
OildatlnE flame, IIH, IM. 
Oxldlsabfe metals, 156. 
Oxides, infusible, 144. 

fusible, 145. 

reduction byjeda, lOB. 
Oxfgea gu reteli, 800. 



for fillen, 7S. 
handle for toliei, 3S. 
label* iOr bottles, 874.. 
litmus, 46. 
tunnerlc, 47. 
Paiitlie glass cutter, S4S. 



Piu'lour tkUe experlmentf , S6S. 

Uboratoiy, S63. 
PaBtle uid MoTMr, S. 
Fho>plu.tes detected, 164. 
Phaaplii.te of iod& uid umnoiilk, 

uw u ■ flux, 174, 
Phoaphoreicence, I3S. 
Pluter of PoHa eamenl, 274, tOS. 
Plien, ETE. 
"- - m ctpauleB, IS, 14,86. 

cnicibin, 97. 

cup, 14, 66, 96. 

detacled,14S,156,17S, 176. 

dlBsolT€d, 194, £79. 

fall, 96, les, 160. 



323 

Pi^U4h&p«d holder, 39, 8W, ise. 
Pren, to soflen corks, 366. 
ProductiTB eiperimsntB, liil. 
PulTeritttlon, I, 8. 

precauUona to Uke, 6; 
Pyroilllc apirlt, £1. 






,96. 



Ruk fiir lubM, SSC 
Rupi, 3, £50, 266. 
Re-KtioD, fhat, 45. 
Re-kgent^ tbeir ute, xx, 45, 47, 

bottles for, 86, 3S.' 
Rsceivan combined with retorla, 
194,833. 
fiir coodeuttioii, 19Z, 
197, K9. 



wires, 186, 168, I7B,!04. 

Pneumatic muilpulition, ell. 

mercury trough, porcel&in, SIT. 

■toneware,916. 

inter trougb, elus tube, E£0. 



Potusium, dfsttUttion, £91. 
Potuh detBcted, ISO. 
Pouring into iluki, 15. 
funnels, 68. 
retorts, 195. 
without loai, 69. 
Powders, dried, 90, 196. 

line sepir&ted bam ix 



retorts, 1B6. 
tubes, 15, 105. 
wuhed, 4 70. 
weighed, 15, 68. 
Preclpltuit. GO. 
Frecipit&ting gluaes, £0, 6S. 
Precipitates, 60, 79. 

collected, 79. 
dried, S9, Oa 
re-dlssoived, IS, 63, 



with sodi, 171. 

Redficing flame, 119, 157 

process with sods, 169. 
Reduotlcn of metals, lOS, 119, 156, 
167, 180, 173. 
by gases, ££5. 
by charcDal, 157. 
hy sods, 169, 173: 
RsMg«nt1on in distillation, 197. 
Realn, lolTente of, £75, £76. 
Retort holder, 317, SOB. 

Gay LusBBc'f, 3^, 

183, SSI. 
8el^troem's,39,SD!. 
Retorts, best form, 196, 197. 
bulb tube, £00. 
dome for, 196, 3^9. 
glass, 19B. 

heated, 196. 197, £89. 
how charged, 196 
how siqinirted, 36, 196, 



weighed. 68, 101. 
Precipitation, iviii, 1,6a 



tube, 193, 194, £D6, £33. 

tubulated, 19S, £89. 
Rhodium detected, 149, 166. 
Ring tops for the lamp fumai 



8S, ■ 

Rods, glass, 4& 

use in pimrlng, 69. 
Roasting or BulphureU, 170. ' 
Routine of operations in AnalysJi 
by the Blowpipe, 13i. 



Ruin tor npcrimaitwi, SSI. 

SftfBty tslM, S3L 

Salt bMh, 90. 

MU, fluifallitj, 146. 147. 

Sillpetre. u» of, 1S7, 176. 

Sind bktb, itonewwa, 196, E80. 

copper, 196, SSL. 

for Uoip fiunice, I 
B7. »». 

for Luhme*! fumM 
SO. 

br chftuffer, B). 

tliipl>t«,86,]tT. 
Shi^, Mrt for bkthi, E7. 
8*f u^Mon, 7, 47. 
Satunted lolution, 7. 

8»r, era. 

ScUol libontorv, sea 
Screw cutting, £73. 
Selling of tubei.SSS. 
tiefMroem'9 holder, S9, WS. SS9 
Selenium delected, 136, U6, Ij 

157, 161, 171, 174 
Sepuktor, 191. 
8he*n to cut metil, £7S. 
Slere, 5. 
Sifting, C 

S)llc» delected, 144, iefi,.l6S, 1' 
3!lfcat«a detected, 140, 1B& 
WUca, u«e, 187, 174, 
Silver detected, 14S, IW, 178, 1 

—181. 
Silver ulU ledKtd, 13S, 140, 1^ 

170, 181. 
Simple boOiea, iilM. 
Soda, uM, IBS, 138, 16S, 169. 

detectad, 149. 
Soft cement, 87a 
Solderine, 913. 
Solids reduced to pmtder, S. 
Solubllitf, 6. 
SoluUon, Kill. 1, e, 877. 
fllerclHee on, 16, 
ftdltUted, T. 
of gues, Sfi7. 
rftwoklndi,7. 
Jul, 60, 68. 
veuela for, 7. 
SolTent, 6. 

SolTenls Tor cleansing, 870. 
Spetula, S. 

Hpecific gisTitiei taken, !S6. 
Spirit lamp, glass, 17. 

dicular wick, 19,8) 



Btatni remored, ST8. 
Steel mortar, 4. 
StUl,lS4. 

Improred, IBS, 

itoaeware, Ibr mitll oper*- 

tionSiSBe. 
tin plate, 890. 
Btimra, 48, CS. 
, Stock tube rack, 184. 
Stmeware sppanitus : — 
Dome for dask<, 8fi 
Dome for retorts, 108. £RI. 
Evaporating captulea, £85. 
naiLs,811. 
Gas bottle, 810. 
Gas holder, £14. 
Lamp funwce, 84, saa 



Lengthen 
Oil lamp. 



Jngcj1lnden,8J6i. 
Oil lamp, 8Si. 
Pep for tubes, £64. 
Perforated cjlluder, SI. 
Pneumatic trough, 813. 

At meTCUTjiSI!^ 
Retort, 888. 
Sand baths, 190, 88(1. 
Shelf &r trough 8I& 
Small ring top. 88. 
Spirit lamp, 81 

Still, 381, m. 
Water baths, 881, 885. 
Stoppers, grindlDg. 871. 
I Stoppers, loosening. 871. 

8t<nipers, mineral, 878. 
, Strontlan detected, 144, 150, 171, 
17»— lei. 

Sublimates examined, 197, 161. 
Sublimates, irhat their coloun in- 

dicBta, 167. 
SuMlmation, 8, 108. 

vessels for, 108. 
exercises, 106. 
in tubes, 103, 160. 
Subliming tubes, 104, 16a 
Suckers, E7, 70, 884. 
Sulphates of earths detected, 158, 
1£9, 17a, 176. 
of metala detected, 1% 
173,176. 
Sulphur sublimed, 107. 



Sulphureti detm:ted, 13S, 1S6, 144, 
\eO, 173, 178. 
. Sulphurats reduced, 135,144,166, 
JS8, 160, 170. 
roaited, 17& 
Sulphuretted bydrofea gu pre.