WAT 



and efpecially in the praftice of watering land, they fhould 

 confequently be diminiflied in number as much as poffible 

 in fuch cafes, and thofe of the tide and wind kinds be fub- 

 ftituted in tlieir places, as might be done with great facihty 

 ■in many inftances. See Mill. 



Water, Mother, in Chemijlry. See Crystal. 



Watek Ordeal, or Trial, was of two kinds ; by hot, and 

 by cold water. See Ordeal. 



WATEK-Orj-an. See Organ. 



Water, Petrifying. See Petrifying. 



WATER-Poi/e. See Hydrometer, and Areometer. 



Dr. Hooka has contrived a watcr-poife, which may be of 

 good fervice in examining the purity, &c. of water. It 

 confifts of a round glafs ball, hke a bolt-head, about three 

 inches in diameter, with a narrow ftem or neck, one twenty- 

 fourth of an inch in diameter ; which being poifed with red 

 lead, fo as to make it but little heavier than pure fweet 

 water, and thus fitted to one end of a fine balance, with a 

 counterpoife at the other ; upon the lead addition of even 

 T-o-'o-irth part of fait to a quantity of water, half an inch of 

 the neck will emerge above the water, more than it did be- 

 fore. Phil. Tranf. N° 197. 



WATER-Proof Cloth and Leather. It woujd be very 

 defirable to render the principal articles of clothing impe- 

 netrable to water, provided it could be done without injur- 

 ing the pliability of the cloth. 



The mofl common refource is to line the garment with 

 oiled filk, fuch as is ufed for hat-covers and umbrellas ; that 

 is, filk which has been drefled with a varnifh of drying lin- 

 feed oil, fo as to prevent the admiffion of water. This effec- 

 tually guards the wearer of fuch a garment from becoming 

 wet ; but it is not perfeft, for the outfide cloth can im- 

 bibe moifture, which will evaporate by the wind, and caufe 

 great part of that ooldnefs which renders wet clothes fo 

 prejudicial. 



What would be defirable is, that we fliould give to cloth 

 the fame property which we find in the fur of feveral ani- 

 mals ; the otter, beaver, and water-rat. This is a repellence 

 of water, which when thrown upon the animal rolls off in 

 pearl drops, without wetting the fur in the leaft ; but we 

 obferve this only in the living animal, and when in a Hate of 

 health, for thefe animals are known to be fick when they 

 are found to be wetted after having dived in the water. 

 This perfeftion has not yet been attained, but we (hall proceed 

 to (late what has been attempted, with a view of water- 

 proof varnilhing for cloth. 



Mr. Albert Angel, in 178 1, had a patent for preparing 

 an elaflic varnifli for this and various other purpofes. His re- 

 ceipt is, hnfecd oil, or nut oil, one gallon ; bee's-wax ( yellow 

 or bleached ), one pound ; glue or fize, fix pounds ; verdigris, 

 a quarter of a pound; litharge, a quarter of a pound; fpring 

 or rain water, two quarts; to be put into an iron kettle, and 

 melted down till it forms the compofition. 



Caoutchouc, or elaftic gum, called Indian rubber, is a 

 fubftance which has engaged the attention of philofophers, 

 ever fince it has been known. Its fingular elafticity, its 

 flexibility and impenetrability to water, have caufed it to be 

 confidered as very valuable for this purpofe. 



It is not poffible to effeft the liquefaflion of caoutchouc, 

 by means of heat ; it will melt as well as other refins, but 

 when cooled, it remains liquid and adhefive. Alcohol or 

 fpirit of wine, the ufuaUfolvents of refinous fubflances, do 

 not aCl upon it, nor is it diffolved in water, as gums are ; 

 it was then tried to diffolve it in drying oils, and it was 

 found that by the aid of heat, the caoutchouc may be dif- 

 folved, and form an excellent varnifh, fupple, impervious 

 to air or water, and refilling a long time the aftion of acids. 



Vol. XXXVIIL 



WAT 



With fuch varnifli Meffrs. Charles and Roberts covered 

 their air-balloons. 



Several effential oils, as thofe of turpentine and lavender, 

 aft upon the caoutchouc, even when cold, and thefe are of 

 no great price. The difagreeable fmell of the oil of tur- 

 pentine becomes, perhaps in procefs of time, lefs difagree- 

 able than that of the lavender. 



The oil of turpentine always leaves a kind of fticklnefs. 

 The following procefs is defcribed in a patent granted to 

 Mr. Henry Johnfon of London in 1797, for rendering cloth 

 and other articles water-proof. 



The article to be operated upon, mufl firft be cleanfed 

 from all greafe or dirt by wafhing it with an alkaline folu- 

 tion, and then ftretched in a frame. The water-proof com- 

 pound, as it is termed, is formed by diffolving caoutchouc or 

 Indian rubber in fpirit of turpentine, (the fmell of which is 

 taken off by adding oil of wormwood, and fpirit of wine in 

 equal quantities ; ) this forms a fort of varnifh, which is capa- 

 ble of being fpread, or wafhed over the furface of the leather 

 or cloth, always applying it on the wrong fide of the article, 

 or that fide which is not to be feen. The varnifh is laid on 

 by means of a large piece of Indian rubber, inftead of a 

 brufh or iponge. To conceal the varnifh and make a good 

 internal furface to the cloth or leather, it muft be fifted over 

 vyith fome fubftance, fuch as filk, wool, or coney, cut very 

 fine, in the fame manner as flock paper is made ; and being 

 left to dry, in a few days the flock, by its adhefion to the 

 varnifh, forms a very good lining, at the fame time that it 

 conceals the varnifh. Thefe articles were called by the 

 patentee hydrolaines, and were loudly recommended by ad- 

 vertifements, but never came much into ufe. 



AT. Pelletier's Method of making Varnifh of CaoutchouCy 

 or elaflic Gum, by dijfol-uing it in fulfhuric Ether. — Boil the 

 elaftic gum for the fpace of an hour in common water, by 

 this it becomes foft enough, to be cut into fmall threads ; 

 being thus divided, put it again into boiling water, and keep 

 the yeffel on the fire for about another hour ; this fecoud 

 boiling penetrates the elaftic gum very fenfibly, and deprives 

 it of that hardnefs which it poffeffes in the firft ftate. 



AVhen the gum is thus divided and foftened, put it imme- 

 diately into a matrafs, or any other clofed veffel, containing 

 reftified fulphuric ether. In the courfe of a few hours the 

 ether penetrates the elaftic gum (which fwells veryconfider- 

 ably ), and at the end of a few days the folution is complete, 

 without the afTiftance of heat, provided a fuflicient quantity 

 of ether is made ufe of. 



According to this procefs, the folutions are of a white co- 

 lour and tranfparent ; the heterogeneous and footy particles, 

 which the elaftic gum generally contains, fall to the bottom 

 of the veffel in which the folution is made, and have a footy 

 appearance, fo that by merely decanting the folution it may 

 be obtained very clear. 



Mr. Parrifh and Mr. Ackermann have likewife had pa- 

 tents for the fame objeft ; the latter fucceeded much better 

 than the elaftic varnilhes. 



Water-proof Leather — In the memoirs of the Academy of 

 Sciences at Turin, 1789, is a paper by the chevalier de St. 

 Real, on the manner of rendering leather impermeable to 

 water, without diminiftiing its ftrength or its fupplenefs, and 

 without fenfibly augmenting jts price. M. St. Real fhews 

 that fkins may be tanned in fuch a way as to give this 

 defirable quality to the leather, and in other refpefts with 

 benefit to the tanner, by reducing all the proceffes of the art 

 to the following. 



For ftrong ox or cow leather, which is ufed for making 

 the outer foles of fhoes and boots. 



I ft, Soak the green hides, feparate from each other, in 

 U running 



