354 



THIC CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[Nov. 



include also the cost of delivery npon the Companies' Works. These con- 

 ditions I always iulroduce into iny specifications. 



You may make any use you please of this letter, my object being in 

 this, as in all other instances, the introduction of an article cheaper than 

 those ordinarily in use, and equally eHicient ; and llius to reduce the ex- 

 penditure in Water Works' Establishments. 



1 am, &c., 



Thomas Wicksteed, 

 Engineers' Office, Old Ford, Engineer. 



Nov. IB, 1843. 



(To Messrs. Nasniylh, Gaskell, and Co.) 



Gentlemen, — In reply to your request, I will gladly bear testimony to 

 the superiority of your U'edge Coi lis over any other form with which I am 

 icquaiuted ; and 1 think tliey might be employed with advantage not only 

 'or W ater Works, but also for many other purposes. As you desire it, I 

 *>eg to oU'er the following observations in support of my opinion. 



1st. Your Cocks cost considerably less than the common single-faced 

 Socks. 



2nd. The form insures both strength and durability. 



3rd. They are tight, aud as the attrition or wear is «qual at every part 

 of the faces, I think they will remain so. 



4th. Being double-faced, they will stop the water either way, which is 

 a great advantage. 



iilh. The stuliing-box may be packed without shutting off the water, or 

 emptyin); the mains. 



(ith. If, as I suggested, they should now be made with a simple Nut, 

 instead of the Gland, the packing in the stuffing-box can be screwed up at 

 any time, without opening the grouuil. 



ith. The ordinary sizes employed fur Service Cocks, even under a pres- 

 suie of 150 feet, are very easily opened aud shut ; after the first few turns 

 they may be moved without tlie aid of a bar, but simply by applying the 

 hand to the key ; should the pressure be great, it may be partly balanced 

 by causing the water to act against the taper side of the slide. 



8th. As a consequence, the keys carried by the Turncocks may be made 

 much lighter than iliey generally are. 



itlh. As we can at all tim"S depend upon your Cocks, being assured 

 they will not allow the water to pass, I can rely, with confidence, upon 

 the indication of my Instrument for discovering faults in the Pipes. 



I may mention, finally, that your Cocks also possess the advantages com- 

 mon to some others, such as a free uninterrupted Water-Way; opening 

 and shutting gently and gradually ; standing low, so that they may be em- 

 ployed even where the Pipes are near the surface ; &c. 



It appears to me that there is but one objection which may be urged 

 against them, which is the probability of the faces rusting or corroding. 

 If they were seldom opened or shut such an effect might ta^e place, but if 

 used frequently I consider there is no risk. 1 have lliis day examined a 

 Cock put down in August, 1845, and I found it in excellent condition, 

 with no appearance of injurious corrosion. 



I will but add, that you are at liberty to make any use you please of 

 this communication. 



I remain, &c., 



Michael Scott, 



Liverpool Water Works, Engineer. 



February 4, 1847. 



PIGMENTS OR PAINTS. 



James Murdock, of Staple-inn, Middlesex, for " an improved mode 

 of preparing ajid employirg certain culoiirs and materials for jjaint- 

 zng." (A communication.) — Granted MarclilU; Enrolled September 

 lU, 1847. [Reported in the Palent Jour7iat.'] 



This invention has for its object the substitution of certain sub- 

 stances unacted upon by sulphuretted hydrogen, instead of the com- 

 pounds of lead and copper at present in use, as pigments or paints, 

 particularly with reference to the greens, yellows, and reds. The 

 patentee describes his iiu'enliun under dttferent heads, as follows: — 

 1st. in a certain process for the iiianufacluring, upon a large scale, of 

 zinc yellow (chrumate of zinc); barytes yellow, untiinoiiy red (sul- 

 phuret of iintimony), and zinc green. 2nd. The employment of these 

 exjiours for pointing, in general, upon cloth, wood, walls, paper, &c. 

 3rd. In the mixture of these colours with others, unaffected by sul- 

 phuretted hydrogm. 4th. lu mixing the oxide of ziiic with other 

 unalterable colours, ath. The manufacture of a new dryer, in which 

 certain peroxides act the same jiatt as litluiige in the common pro- 

 cess. 6th. A process of |)olishing painting with oxide of zinc and un- 

 alterable colouis, combined with the dryer above mentioned. 7. The 

 application ot the above-inentiomd colours and oxide of zinc in print- 

 ing and colouring paper-hangings. The patentee then proceeds to 

 describe his processes; and, in the first place, Ins ziuc yellows. This 

 process is divided into three parts. i3y the first he obtains what he 



calls marigold yellow. For this purpose he mixes in a boiler 120 lb. 

 of bichromate of potass with from 700 to 800 lb. of water, and 60 lb. 

 of "zinc white." The boiling is continued for from 24 to 3G hours. 

 The precipitate is then separated and washed, and the first w.ishings 

 added to the solution from which it was precipitated. When per- 

 fectly washed the precipitate is dried, and either reduced to powder 

 or made up into cakes. By the second he obtains lemon yellow, by 

 adding to the solution which remains from the first process, together 

 with the washings which were added to it, sulphate of ziuc, formed 

 by adding to 75 lb. of oxide of zinc, 45 lb. of sulphuric acid of coro- 

 merce, of specific gravity (J3J°. This is to be boiled as in the first 

 process, and the precipitate separated, washed, and dried. To the 

 solution remaining from this last process, together with the first wash- 

 ings of the precipitate, he adds sulphate of zinc, formed by adding to 

 15 lb. of oxide of zinc 7 lb. of sulphuric acid of commerce. This is to 

 be boiled as before, and the precipitate washed and dried. This 

 gives a pale yellow, of a tint between the marigold and citron tint 

 above described. The baryta yellow is funned by adding to a solu- 

 tion containing 100 lb. of chloride of barium, 84 lb. of the double neu- 

 tral chromate of potass and soda, boiling these together, then separat- 

 ing, washing, and drying the precipitate. From these yellows tlie 

 patentee says he can obtain any shade of yellow required by adding, 

 if necessary, raw terra sienna, or the antimony red hereafter described. 

 And greens in the same manner may be obtained of any shade, by add- 

 ing to the yellows a blue, unacted upon by sulphuretted hydrogen. 

 The antimony red, or orange red, is made by dissolving the native 

 sulphuret of antimony in hydro-chloric acid, in such proportion that it 

 will just dissolve the whole of the sulphuret; this proportion the pa- 

 tentee finds to be about of acid to 1 of the native sulphuret. Tl)e 

 solution is then filtered, and water or acid is added to it until its 

 specific gravity is between 13° and 17° of the French arioraetre. The 

 patentee prefers 16°, but claims all degrees between 13^ and 17°. 

 When the solution has been brought to the above density, it is placed 

 in a suitable vessel, and sulphuretted hydrogen passed through it. 

 The sulphuretted hydrogen may be that evolved in forming a second 

 solution of the native sulphuret. The tube by which the gas is con- 

 ducted into the solution should be of glass, and wide enough to pre- 

 vent its clogging; the vessel should be covered, and the gas made to 

 pass through a series of vessels, and at last conducted into a vessel of 

 milk of lime ; during the process the solution should be stirred occa- 

 sionally with a wooden spatula. The precipitate is to be washed 

 thoroughly, and dried at a temperature of from 100° to 120°; at a 

 higher temperature than this the hydrated sulphuret would lose its 

 combined water, and become black. To form the zinc green, the pa- 

 tentee dissolves in hot water 491b. of pure dry sulphate of cobalt, and 

 to this adds 255 lb. of oxide of zinc slaked with a little water; th« 

 whole is then boiled to dryness, and heated red-hot in a muffli. The 

 calcined mass must then be cooled and thrown into water, thoroughly 

 washed and dried. The patentee claims this his process of neutra- 

 lising the sulphate of cobalt with oxide of zinc. The patentee next 

 describes the process for making a dryer, or drying oil, by boiling for 

 6 or 8 hours 200 gallons of purified linseed oil, aud then adding to 

 this 101b. of peroxide of manganese in fine powder. The mixture is 

 to be boiled for 5 or 6 hours, and filtered when cool. Peroxide of 

 iron will answer the purpose, but it is not so effective as peroxide of 

 manganese. If desired, the protoxide, sulphate, acetate, or cap- 

 bonate of manganese may be used. This dryer may be mixed with 

 the paint in tlie proportion of 1-lOth to l-201h. Instead of the dryer 

 above described, the peroxide of manganese may be ground up with 

 the paint in the same manner that litharge is now employed. It 

 should, in such case, be used in the pioportiou of 1-lOth to l-25th. In 

 applying his patent colours for the purpose of polished painting, the 

 patentee lays on, first, several coats ot zinc white, and when dry the 

 surface is rubbed down with pumice till it is brought to a dead polish. 

 The colours, whether for marbling, graining, & ■., previously mixed 

 with the dryer are then laid on, and when dry will not require varnish. 

 In applying these colours to paper-hangings no alteration whatever is 

 required to be made in the common process, and for the purpose of 

 satining or watering paper, or enamelled cards, the zinc white is em- 

 pluved instead of the white lead now counnonly used. The patentee 

 claims: — 1. The particular mode of manufacturing zinc yellow, 

 baryla yellow, orange red (sulphuret of antimony; and zinc green. 2. 

 The application of the above colours to paintiug pictures, buildings, 

 and other objects, upon stoue, wood, plaster, canvas, paper, &c. 3. 

 The manufacture of compound colours made of zinc yellow, antimony 

 rid, baryta yellow, "zinc white." 4. Compounding the above colours 

 with linseed or other oils, and the dryer above describid. 5. Tlie 

 mixture of the dryer above described with unalterable colours, whether 

 those above mentioned, or others containing neither lead nor copper, 

 or compounds containing those colours above described, and other un- 



