mass collected in the cooled vessel F, from which it is pumped through pump P into a filter press. The crystals are then introduced as an intermediate product at a suitable stage of the process into the crude candle material. The oleic acid may be converted as far as possible into solid candle material in the manner shown above.

If the raw candle material charged into the autoclave be of inferior quality and incapable of yielding white stearine by expression, then the total mass from the autoclave is acidified, i.e., treated in the manner described already under the acid saponification process, and separated after distillation into stearine and oleic acid.

The hot pressed stearine is then ready to be moulded into candles. This is done in well-known machines, like that shown in the later part of the lecture (Fig. 23), with that difference that in the latter machine the bobbins on which the wicks are wound in a candle-moulding machine are left out.

The moulded candles, before being placed on the market, are polished, washed, dried, and finally branded, if required, in a set of machines which I show in a series of lantern slides.

Owing to the expensiveness of stearine, paraffin wax is being largely used in admixture with stearine. A series of cast blocks of candle materials representing mixtures of "stearine" and paraffin wax in various proportions are exhibited on the table here. (To be continued.)

Miscellaneous.

THE HOUSING QUESTION.* There is a great and complex interaction between a house, its surroundings, and its occupants. If homes are to be made more wholesome, all these three factors must be improved. Our schools must give better moral training for life, and their influence must be extended by continuation classes. Houses must be put into, and maintained in, good order by a system of continuous inspection. In new districts houses must have pleasant surroundings, the air must be kept as free from smoke as possible, and the dwellings of persons of different social classes must be intermixed. While the building of tall tenement houses must be prevented, the "one-family house"

• Paper read by T. C. Horsfall before Section F of the British Association.

should cease to be the predominant type of workman's house in and quite near to large towns. The growth of towns should be controlled by extension plans, and building districts should be created-some reserved for manufactories, and others for dwellings. In the districts more remote from the centre, houses should not be allowed to have as many storeys, and sites to have as large a proportion covered with buildings, as are allowed in districts nearer the centre of the town. Town councils should have the power to buy and hold land for general purposes, to rate land on its selling value, and to levy rates on increase of value when property is sold. The incorporation of surrounding districts by large towns should be made much easier. Tramlines ought to be made by town councils, but not till much land has been bought and a town extension plan prepared. Town councils ought to be strengthened by the employment of paid mayors and chairmen of committees, who ought to be appointed for long periods.

General Notes.

COMMERCIAL EDUCATION.-The City of London College, which opened for its 57th session on Saturday, is inaugurating a scheme of commercial education. A day clerical commercial school is to be opened, and later on a higher commercial school will be established. In the evening classes the work will be systematised, and courses will be commenced, extending over two or three years, in banking, the various branches of insurance, for accountants, for those engaged in secretarial work, for surveyors, and for those engaged in merchants' offices. An extensive school of modern languages will be opened, and not only will the French, German, Spanish, Portuguese, and Dutch languages be thoroughly taught, but in French and German, persons who are actually engaged in commerce will give instruction in the business methods and commercial and mercantile institutions and documents of France and Germany.

SCHOOL OF ART WOOD-CARVING.-The School of Art Wood-carving, South Kensington, which now occupies rooms on the top floor of the new building of the Royal School of Art Needlework in Exhibition-road, has been re-opened after the usual summer vacation, and some of the free studentships maintained by means of funds granted to the school by the London County Council are vacant. The day classes of the school are held from 10 to 1 and 2 to 5 on five days of the week, and from 10 to 1 on Saturdays. The evening class meets on three evenings a week and on Saturday afternoons. Forms of application for the free studentships and any further particulars relating to the school may be obtained from the manager,

several days, attempts have not been wanting to shorten the time required for cooling from

Whereas the chief care of the candlemaker is directed to obtain as much free fatty acid, and especially solid acids, as possible, the main object of the soapmaker is to obtain all the fatty acids in the form of soap, i.e., in the form of sodium or potassium salts of fatty acids. Hence, he will, when hydrolysing his fats, use as an accelerator only such a base as will yield him straightway hard soaps-sodium salts, or soft soaps-potassium salts. In other words, the soapmaker hydrolyses (saponifies) his oils and fats with caustic soda or with caustic potash, in an open pan, and converts, by the well-known suitable treatment, the soda salts into a mass which on cooling in large frames -soap frames (a model of which I show here) -solidifies, in the course of a few days, to a solid block. The sides of the soap frames are then removed, and the rectangular block of soap left is first cut into slabs of the required thickness, either by hand, or by a machine such as shown in Fig. 21, and then into tablets by a machine such as shown in Fig. 22.

As the solidification of the soap requires

conversion of the solidified soap into the marketable bar or cake.

I have attempted to effect this by sending the soap through a long worm, cooled artificially*, but the soap so obtained represented an unsaleable mass, owing to the crystalline structure of the soap having been destroyed. Another attempt to effect this rapid solidification of the hot soap mass was made by moulding the soap in the same manner as candles are moulded.† The machine used for this purpose (Fig. 23), is fashioned after the well-known candle moulding machine. It was chiefly intended for the manufacture of toilet soaps, in which the crystalline structure, so much valued in household soap, is destroyed. The hot soap mass was run into the several moulds shown in the figure, and after suitable cooling, the solidified soap was expelled in the same manner as moulded candles are forced out.

At

This machine proved unsuitable for household soaps, but the idea underlying the construction of this machine has been recently taken up and patented by Schnetzer. present nothing can be said as to the success obtained by his plant. Another attempt to shorten the time required for solidification has been made by Klumpp, whose press is best described as being fashioned after a copying press, the sides of which are completely closed. The hot soap is run into the press, and when full, the soap is cooled rapidly and compressed, so that the soap bars are immediately ready for being divided into tablets. A combination of the principles embodied in these two patents may be said to be contained in Schrauth's patent.

We have learned from the fundamental equation representing the hydrolysis of fats (Lecture III., Equation 1, p. 823), that glycerin results as the second product. The candlemaker obtains the glycerin in an aqueous solution. The soapmaker, however, who produces hard soaps in an open pan, obtains his glycerin in a solution containing a large amount of salt, alkali, and impurities, but so small an amount of glycerin that up till about two decades ago the soapmaker's so-called "spent lyes" were run away into the nearest watercourse.

Lewkowitsch, "Problems in the Fat Industry," Journ. Soc. Chem. Ind., 1903, 597.

+ English Patent, No. 4581, 1893.

in this country recovers the glycerin from the spent lyes.

It may as well be pointed out that this country has taken a leading part in this industry, and was practically the first to recover glycerin from the soap lyes on a large scale. America and France have followed suit, and the most prominent soapmakers there now produce glycerin from their lyes.

In other countries, where the soapmaking industry has not yet reached the rank of the important chemical industry it really is, and where it is only slowly emerging from the stage of a house industry, the recovery of glycerin is still in its infancy. This is chiefly due to the fact that soapmaking is in the hands of many small makers, so that in a

process has indeed been practised in a number of candle works. The oleic acid was there converted into soap by boiling with caustic soda, or more simply still with sodium carbonate, a process which, theoretically, is identical with that of neutralising, say, hydrochloric acid by sodium carbonate.

The products which the candlemaker thus obtained being dark, the soaps so produced were dark and of evil odour. This method has again been taken up lately on the Continent, but in order to minimise the darkening effect which the fatty acids must suffer in an autoclave, the pressure was reduced, and thus a better looking product was obtained than from material autoclaved at the high temperature. This mo lification has, however, that important

drawback that saponification cannot be carried on to the end, and products are obtained which contain 15 to 20 per cent. of unsaponified fat. The glycerin contained in this unsaponified portion of fat is irretrievably lost, as it does not pay to recover it from the lyes obtained in the soap pan.

These "improved" processes are being put on the market as new or "patented" processes with a great flourish of trumpets and an amount of advertising in the trade papers, which betrays too openly the interest that some makers of autoclaves have in pushing their wares. There are no less than about 40 processes on the market, each of which claims to work with an autoclave of its own, or, if you like, about 40 different autoclaves, each of which is worked with a "special process."

After what I have said before, I need not point out that these patents are valueless, and it is not a little amusing to see the travelling agents for these autoclaves on their visit to this country shake their heads mournfully over the backward state in which our chemical manufacturers in general, and our soapmakers in especial, are still found.

Of course, these methods have been tried long since in this country, and have been found wanting, as the soap so obtained is unquestionably darker and unsaleable, at any rate in this country, at its proper price. On the Continent these processes may commend themselves to some extent to those soapmakers, who have hitherto wasted their glycerin, and who are able to sell a soap at which an English