430 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



De 



C E M IS E R , 



with matter, and liave velocity adequate to cause a conflicting action ■with the 

 water of tlic ocean, then in that case a deposit or bar would ensue. But in 

 all my extensive and practical observations, I know of no river, nor is tliere 

 an instance to be found in our globe, where a river at its disemboguing ;;f>i»/ 

 and where it mefls the tidal water of the ocean, and commences the conllict- 

 ing no/(0«,docs jiass out or meet the tide at an acute, but im-arinbly sA a right 

 angle. Surely no scientific or practical man can be so iminformed as not to 

 know that however meandering may be the interior cou'se of a river, ere it 

 arrives at the ocean, nalurnUy and necessarily, it must take a perpendicular 

 course into the sea, and continue that course till influenced by the ocean's 

 tide. In some places this i>erpendicular or right angle course into the sea is 

 by a long, in others by a short sea-reach. 



Mr. Brooks has mistaken the fact, the important distinction between that 

 course or direction of the river water at its fall into, and until it absolutely 

 gets in contact with the tidal water: and that direction which it takes sub- 

 sequent to the joining of the two waters. It is the pressure of the larger 

 and heavier power of the sea tide, passing parallel with a coast, and conse- 

 quently crossing the month of a river at right angles, which forces the water 

 from a river to incline to the direction of the more powerful stream ; and 

 thus the river water takes an oblique or an acute angle of direction from its 

 uninfluenced course — but for this cause, a river would continue to advance 

 seaward in its perpendicular direction until it was exhausted, and disappeared 

 in the vast ocean. 



We see then the cause why all bars are formed on the lee-side of the en- 

 trance to a harbour, if the ebb tide come from the right, the bar invariably 

 inclines towards the left, and rice versa. 



In making these observations I beg it may be understood that they relate 

 onli/ to a coast where there are regidar passing tides. 



I remain. Sir, your obedient servant, 



Henry B.\rrett. 



72, Broughion Street, Edinburgh, 

 November IT, 1S41. 



DREDGE'S SUSPENSION BRIDGE. 



Sir — An entire description of my patent suspension bridge would occupy 

 too much space in your Journal, and employ more time than I can at present 

 spare, and as an abridgment, would perhaps produce more cavilling thau 

 would be interesting to your readers, or necessary for the investigation of 

 truth, I will refer Mr. Fordham to a full mathematical description, which 

 will l)e published in a few days, by Mr. \Vcale, to four foot bridges in the 

 vicinity of the Regent's Park, and similar works in various parts of the king- 

 dom, so that as a mathematician, and man of science, be may be able to 

 read, see, and judge for himself, and from these evidences, form what opi- 

 nion he thinks fit, and I shall be most happy to see that opinion publicly 

 expressed through the medium of your pages. 



I remain. Sir, 



Your obedient servant 



J. Dredge. 



METHOD OF PREPARING AND APPLYING A COMPOSITION FOR 



PAINTING IN IMITATION OF THE ANCIENT 



GRECIAN MANNER. 



BY EMM.V J.\NE HOOKER. 



Pi'T into a glazed earthen vessel, four ounces and a half of gum-arabic, 

 and eight ounces , or half a pint (wine measMe) of cold spring water ; when 

 the gum is dissolved, stir in seven ounces of gum-mastich, which has been 

 washed, dried, picked, and beaten fine. Set the earthen vessel containing 

 the gum-water and gum-mastich over a slow fire, continually stirring and 

 beating them out with a spoon, in order to dissolve the gum-mastich : when 

 sufficiently boiled, it will no longer appear transparent, but will become 

 opaque, and stiff, like a paste. As soon as this is the case, and that the gum 

 water and mastich are quite boiling, without taking them off the fire, add five 

 ounces of white wax, broken into small pieces, stirring and beating the 

 different ingredients together, till the wax is perfectly melted and has boiled . 

 Then take the composition off the fire, as boiling it longer than necessary 

 would only harden the wax, and ])revent its mixing so well afterwards with 

 water. When the composition is taken off the fire and in the glazed earthen 

 vessel, it should be beaten hard, and whilst hot (but not boiling) mix with it 

 by degrees a pint (wine measure) or sixteen ounces more of cold spring 

 water; then strain the composition, as some dirt will boil out of the gum- 

 mastich, and put it into the bottles: the composition, if properly made, 

 should lie like a cream, and the eolo\irs, when mixed with it, as smooth as 

 with oil. The method of using it is to mix with the composition, upon an 

 c.irtlien pallet, such colours in powder as are used in painting with oil, and 

 such a quantity of the composition to be mixed with the colour as to render 



them of the usual consistency of oil colour ; then paint with fair water. The 

 colours, when mixed with the composition, may be laid on, either thick or 

 thin, as may best suit your subject, on which account this composition is very 

 advantageous, where any particular transparency of colouring is required; 

 hut in most eases, it answers best if the colours be laid on thick, and they 

 require the same use of the brush, as if painting with body colours, and the 

 same brushes as used in oil painting. The colours, if grown dry, when 

 mixed with the composition, may be used by putting a little fair water over 

 them ; but it is less trouble to put some water when the colours are observed 

 to be getting dry. In painting with this composition, the colours blend 

 without difficulty when wet, and even when dry the tints may easily be 

 united, by means of a brush and a very small quantity of fair water. When 

 the painting is finished, put some white wax into a glazed earthen vessel over 

 a slow fiie, and when melted, but not boiling, with a hard brush cover the 

 painting with the wax, and when cold take a moderate hot iron, such as is 

 used for ironing of linen, and so cold as not to hiss if touched with anything 

 wet, and draw it lightly over the wax. The painting will appear as if under 

 a cloud till the wax is ])erfectly cold, as also, whatever the picture is painted 

 upon is quite cold; but if, when so, the painting should not ai>pear suflici- 

 ently clear, it may he held before the fire, so far from it as to melt the wax 

 but slowly ; or the wax may be melted by holding a hot poker at such a 

 distance as to melt it gently, especially such parts of the picture as should 

 not .ippear sufficiently transparent or brilliant ; for the oftencr heat is applied 

 to the picture, the greater will be the transparency and brilliancy of colour- 

 ing ; but the contrai-y effects would be produced if too sudden or too great a 

 degree of heat were applied, or for too long a time, as it woidd draw the was 

 too much to the surface, and might likewise crack the paint. Should the 

 coat of wax put over the painting when finished appear in any part uneven, 

 it may be remedied by drawing a moderately hot iron over it again as before 

 mentioned, or even by scraping the wax with a knife; and should the wax, 

 by too great or too long an application of heat, form into bubbles at parti- 

 cular places, by applying a poker heated, or even a tobacco-pipe made hot, 

 the bubble will subside ; or such defects may be removed by drawing any- 

 thing hard over the wax, which will close any small cavities. 



When the picture is cold, rub it with a fine linen cloth. Paintings may 

 be executed in this manner upon wood, (having, first, pieces of wood let in 

 behind, across the grain of the wood to prevent its warping), canvas, card, 

 or plaster of Paris. The plaster of Paris would require no other preparation 

 than mixing some fiue plaster of Paris in powder with cold water the tliick- 

 ness of a cream ; then put it on a looking-glass, having first made a frame of 

 bees-wax on the looking-glass, the form and thickness you would wish the 

 plaster of Paris to be of, and when dry take it off, aud there will be a very 

 smooth surface to paint upon. Wood and canvass are best covered with 

 some grey tint mixed with the same composition of gum-arabic, gum-mastich, 

 and wax, and of the same sort of colours as before mentioned, before the 

 design is begun, in order to cover the grain of the wood or the tlireads of 

 the canvas. Paintings may also be done in the same manner with only gum 

 water and gum-mastich, and wax ; but instead of putting seven ounces of 

 mastich, and when boiling, adding five ounces of wax, mix twelve ounces of 

 gum-mastich with the gum water, prepared as mentioned in the first part of 

 this receipt ; before it is put on the fire, and when sufficiently boiled and 

 beaten, and is a little cold, stir in by degrees twelve ounces or three-quarters 

 of a pint (wine measure) of cold spring water, and afterwards strain it. It 

 would be equally practicable, painting with wax alone, dissolved in gum 

 water in the following manner. Take twelve ounces or three-quarters of a 

 pint (wine measure) of cold spring water aud four ounces and a half of gum- 

 arabic, put them into a glazed earthen vessel, aud when the gum is dissolved, 

 add eight ounces of white wax. Put the earthen vessel with the gum-water 

 and wax upon a slow fire, and stir them till the wax is dissolved and has 

 boiled a few minutes ; then tiike them off' the fire and throw them into a 

 basin, as by remaining in the hot earthen vessel the wax would become 

 rather hard ; beat the gum-water and wax till quite cold. .\s there is but a 

 small proportion of water in comparison to the quantity of gum and wax, it 

 would be necessary, in mixing the composition with the colours, to put also 

 some fair water. Should the composition be so made as to occasion the 

 ingredients to separate in the bottle, it will become equally serviceable if 

 shaken before used to mix with the colours. 



I had lately an opportunity of discovering that the composition which had 

 remained in a bottle since the year 1792, in which time it had grown dry and 

 become as solid a substance as wax, returned to a cream-hke consistence, and 

 became again in as proper a state to mix with colours, as when it was first 

 made, by putting a little cold water upon it, and suffering it to remain a 

 short time. I also lately found some of the mixture composed of only gum- 

 arabic water and gum-mastich, of which I sent a specimen to the Society of 

 Arts in 1 792 ; it was become dry. and had much the appearance and consis- 

 tency of horn. I found, on letting some cold water remain over it, that it 

 becaiue as fit for painting with as when the composition was first prepared. — 

 The Art Vnion. 



.■Inelegant painted uindow, designed ami e.xeculed I y Mr. Willement. of 

 London. "has just hem erected in St. Georges Chapel, Edgbaston, by the sub- 

 scriptions of the corgregation. 



