10 



DESCRIPTION OF A MILL-DAM AND BRIDGE. 



[1852 



to the fjibrication of artificial or fancy flowei-s. M. Grenet, wlio 

 Avas the firet to fabricate on a large scale, out of various residues 

 of animal bodies of little value, these beautiful and diversified 

 product?, many of wliicli previously had been derived from the 

 more costly substauce^singlass, was deemecT by the jury to 

 merit the award of the council medal. 



Manv manufacturers in France have risen to great eminence 

 in this line by following the processes of M. Grenet. H. Castelle, 

 of Paris, exhibited (No. 107) a still more varied assortment of 

 the modifications of gelatine, amongst which were particularly 

 deserving of notice the very large sheets of transparent gelatine, 

 colourless, white, of various well-defined colours, and embossed or 

 stamped with elegant patterns. 



Jacob Bell, Esq., M. P., in his lecture on pharmaceutical pro- 

 cesses and products, gives a curious illustration of the extent to 

 which tlie consumer is prejudiced by the obstacles which inter- 

 vene between himself and producer : — 



An ingenious application of the science of chemistry consists 

 in the manufacture of artificial essences of pears, pine-apples, and 

 other fruits. A few specimens which I have received from Mr. 

 Piper, of Upper Winchester Street, Penton-sille, are on the table. 

 In the concentrated form, the smell is rather aaid, but when 

 diluted, the resemblance to the fruit is recognised. The best 

 imitations are the pine-apple and the jargonelle pear; the green 

 gage, apricot, black cui-rant, and mulberry, when properly mixed, 

 are fair imitations. They are quite innocuous in the proportions 

 used, namely a drop or half a drop to the ounce. I have been 

 informed, that some of the ices furnished in the Great Exhibition 

 were flavoured with these essences. The introduction of these 

 preparations originated, I believe, in the discovery of the fact, that 

 the pecuhar flavour of " pine-apple rum" was due to butyric ether, 



which has since been obtained from the fruit itself. Fmther 

 experiments led to the discovery of other artificial essences. 



Here is a series of specimens of scammony from tlie English 

 collection. No. 1 ispm-e; the others are more or less adulterated, 

 down to No. 5, which is not worthy of the name of scammon}'. 

 In the Turkish collection, where we might have expected to find 

 scammony unusually fine. No. 1 is about on par >vith No. 3 in 

 those above mentioned, and No. 5 would not be recognized as 

 seammonj' except by the label on the botttle. It is only witliin 

 a few yeare that pure scammony has been known in England, 

 and its introduction arose from the circumstance of several sam- 

 ples of scammony being analysed, and found to be adulterated 

 (chiefly with starch and chalk) to an extent varying from about 

 15 to 60 per cent The fact being reported to the merchant 

 abroad, he rephed, that he made it to suit the demand, and 

 mixed it according to the price. He said he would send it pure 

 if desired, but it would be dear in proportion. From that time, 

 " virgin scammon}'," as it is called, has been in the English 

 market, but it has not yet foimd its way to the continent of 

 Europe. Several foreign professors, lecturers ou materia medica, 

 and possessors of extensive museums, had never seen pure scam- 

 mony until they saw it at the Great Exhibition, and were glad 

 to obtain a few ounces as a specimen, to take home with them as 

 a curiosity. Similar remarks may be made with regard to opium, 

 of which we had specimens from various localities. This is a 

 drug which, like many othera, is adulterated to suit the demand. 



Note — We are indebted lo Ihe liberality and courtesy of the Proprietors of 

 the lliii^ilraled London IVeWs for the stereotyped plate of the Canadian 

 Department of the Great Exhibition. We have also been favoured with 

 stereotyped plates of various articles contributed by Canadians, which we 

 shall introduce into the Journal as occasion offers. We beg lo tender our 

 respectful thants to the Proprietors of the Illustrated London News. 



Description of a Alill-Dam and Bridge for a Creek Fifty Feet Wide. 



We would remind those of our professional brethren whose 

 mincls may so;u' above the preparation of a plan for a Mill-dam 

 or a Bridge across a creek fifty feet wide, and who may be 

 tempted to smile at the common-place nature of the work we now 

 illustrate, tliat one object of the Canadian Journal is to impart 

 information on matters of common necessity among the jieople, 

 in the full con\iction that the efficient and permanent constmction 

 of such bumble works is as essential, in theh' several localities, to 

 the general progress of the country, as are those of far gTeater 

 magnitude. In fuitherance of this purpose, we im-ite the 

 co-operation of all whose attention has been given to these 

 subjects, not without the confident expectation that the ex- 

 ample set by our inteUigeut correspondent, whose diagrams 

 and descriptions we 

 give below, wUl be 

 generously followed 

 by many practical 

 men,whose experience 

 will enable them to 

 furnish nititerials pos- 

 sessing that rare value 

 which experience a- 

 lone can give. 



The drawings I 

 enclose in this com- 

 munictition were made 

 for a Mill-dam and 

 Bridge acro.ss a creek, 



bed of soft clay. A dam had been previously constructed on the 

 same site, hut had been twice carried away, o^rfng to the sudden rise 

 of water, wa.shing away and undermining the banks on each side of 

 the abutments. In order to jjrevent the recurrence of suuilar acci- 

 dents it was necessary to construct a dam vnth a very wide water 

 way or apron ; and to connect tlie abutments with the banks by 

 puddle ditches aud shut pihng, as well as to construct the sluices 

 in such a manner as to admit of the water-way being readily 

 enlarged to such an extent as to allow the passage of the water 

 duiing the heaviest freshets without allowing it to rise above the 

 abutments. These conditions are fulfilled by the design which 

 I will now briefly describe. 



The bed of the creek was first excavated to a depth of three 

 feet below its ordinaiy lexel under the whole breadth of the dam, 

 ('one half the breadth of the creek being completed while the 



other half served fur 

 the water, 

 I the dry 

 season w.^s inconsi- 

 derable,^ round piles 

 1 2 inches diameter 

 were driven to a 

 depth of about 12 

 feet, as indicated on 

 the plan, to which 

 the cross timbere are 

 notched and bolted — 

 upon these longitudi- 

 nal timbei's are pla- 

 ced and secured. The 

 second row of piles 

 from the upper side, 

 being square, are left 



the banks of which were about 120 feet apart, and of deep loam, the sufficiently high to receive the cap piece of the apron, which is 



