« EelmineJätka »
J. & A. CHURCHILL, NEW BURLINGTON STREET ;
VOL VII.-JULY 1, 1876.
A SOURCE OF DAMAGE TO LINEN, ETC., ' marks of the device, and that the parts immediately
MARKED WITH INK CONTAINING adjoining still retained their natural strength and SILVER.
capability of resisting strain. But though the inBY B. H. PAUL.
jury which the fabric had undergone was thus When linen etc., has been marked with any of the obviously connected with the presence of the markordinary varieties of marking ink containing silver, ing ink upon the linen, it was not difficult to arrive it sometimes happens that the fabric becomes só at the conclusion that however plausible the above weak at the part where the letters are traced that mentioned attempts at explanation might appear at the least exercise of force suffices to produce a rent; first sight they would not bear the test of minute and if the material marked is of delicate texture it examination. The marking ink on examination is especially liable to injury in this way.
| proved to be free from uncombined acid; it was in A similar effect was sometimes produced when fact strongly alkaline, and like the majority of such marking ink was used which required the applica- preparations it was a silver salt that had been
ion of heat to the linen after the mark had been rendered ammoniacal, and there was nothing to Written, and it was then ascribed to the overheating support the idea that it could produce any corrosive of the iron under which the marked linen was pressed. effect. Still less probability attached to the idea That this was, in some cases, the real cause of the that the fibres of the linen had been damaged by the injury is very probable, but no such explanation of mechanical pressure of the stamp used in marking the effect above mentioned is admissible as regards the linen, for the force required for that purpose marking ink that does not require the application of would be quite inadequate to cut the fibre. a hot iron to bring out the mark.
In addition to the absence of any acid from the Quite recently I had occasion to examine a quan- marking ink that had been used in this case, it was tity of linen which had been affected in the way further observed that the linen which had not been described. It was a new supply of house linen to a washed at all was free from any injury: and since publie establishment, and each article had been those articles would retain the whole of the ink marked with a well-known kind of marking ink printed upon them and be more fully exposed to by means of a bos-wood stamp. The mark con the influence of any corrosive ingredient than the sisted of a monogram surrounded by a garter form- articles which had been washed, it became quite irg a cirele about two inches in diameter. This was evident that the damage presented by the linen was printed upon the linen in the centre of each article, not referable either to the presence of corrosive inand after the linen had been for some little time in gredients in the marking ink or to the weakening of use the fibres gave way exactly at the places where the fibre by the direct action of the ink. At the the ink marks were situated, so that eventually a same time there was an evident connection between piece came away altogether, leaving a hole correspond the occurrence of the damage and the washing of the ing in size to the device marked on the articles. This linen. Those articles which had been washed once happened in so many instances and so soon after the or twice showed no sign of injury, or at least very linen had been taken into use that it became a very slight injury, while in the case of others which had serious question who was responsible for the damage. been washed a dozen times there were holes corre
Several conjectures were started to account for the sponding to the place where the mark had been, or results observed, and among the first to be put the marked parts of the linen were so weakened that forward was the idea that the marking ink, being a they tore asunder with the least strain. chemical preparation, must have contained some However, it was ascertained that mere washing thing of an 'acid or corrosive nature which had was not in itself sufficient to cause the damage burnt the linen. Others assumed that the fibre of which the linen had undergone, for two of the linen had been cut by the pressure exerted upon the marked articles subjected to this operation it when the marking was done with the box-wood with ordinary soap and water about a score times stamp, or at least so much weakened in this way that and in a rougher manner than usual, failed to show it subsequently tore more readily than the adjoining any signs of injury such as that complained of. portions upon which no pressure of the raised parts of Even after boiling one of these articles subsequently the stamp had been exercised. Both of these sugges- for an entire day in a strong solution of soda it retions were consistent with the appearance of the mained quite sound at the parts marked as well as damaged linen, for on examination it was easily elsewhere. It appeared, therefore, clear that the recognizable that the injury was very sharply injury was not the result of any influence necessarily limited to those parts of the fabric which bore the appertaining to the washing operation, and further,
THIRD SERIES, No. 314.
that there was a probability of its being due to some NOTE ON SO-CALLED WOOD OIL. thing abnormal in the way that operation had been carried out in this case.
BY PROFESSOR F. A. FLÜCKIGER. The evident connection between the extent of In a note conmunicated to the Archiv der Pharinjury and the number of times the linen had been macie, for May, the author states that he has found washed showed that the action was gradually pro- that the ethereal oil of Dipterocarpus balsam, known gressive, and the local connection of the injury in as Gurgun balsam or wood oil, when dissolved in the linen with the marks of the ink likewise indi- about 20 parts carbon bisulphide, and a drop of a cated that the substance of which those marks cooled mixture of equal parts of sulphuric and nitric consisted had something to do with the action which acids added, takes a splendid violet colour. A single resulted in damage to the linen. The inquiry was drop of the ethereal oil is sufficient to produce the therefore narrowed to these limits, and as the ink reaction, and the colour lasts several hours. It is mark probably consists of silver oxide, the question not prevented by the presence of resin or by copaiva was, what combination of other conditions besides balsam, so that the reaction takes place with the the presence of that substance would result in corro-crude Gurgun balsam, or even when that is mixed sion of the linen ? Remembering the statement that with eight times its volume of copaiva balsam. The bleaching powder is sometimes used to expedite the reaction can therefore be used to detect the presence whitening of linen, and the fact that oxide of silver of Gurgun balsam in copaiva balsam. Under the same is converted into chloride of silver when brought conditions fish liver and oilof valerian are also coloured into contact with a solution of a hypochlorite, it a beautiful violet, but only transiently so.
In order struck me that the conditions under which this re- to exclude fish oil from the test it is recommended action takes place were such as to be worth examining to distil off the ethereal oil, although on account of with the view of ascertaining whether they might its high boiling point (250° to 260° C.) this is not not furnish an explanation of the damage done to an agreeable task. Only a few drops are required, the linen. The reaction which takes place is repre- however, for the test. sented by the following equation, taking calcium Should a wood oil not correspond to this reaction hypochlorite as being represented by a solution of the author thinks it might probably be due to the ordinary bleaching powder.
fact that some Dipterocarpus trees yield a varying Ag,0+CaCl,0,=2 AgCl + CaO +20. balsam. The balsam is obtained in large quantities Parallel with the formation of chloride of silver from the following species:-Dipterocarpus turbinatus, and lime which takes place in this reaction, there Gaertn. (syn. D. lævis, Ham., D. indicus, Bedd.), is a liberation of oxygen, and the conditions under D. incanus, Roxb., D. zeylanicus, Thw., D. trinervis which the reaction takes place are precisely those Blume, D. littoralis, Bl., Ď. alatus, Roxb., D. hispidus which are favourable to the production of that Thw., D. gracilis, Bl., D.retusus, Bl. All these species allotropic form of oxygen known as ozone. The occur in India and in the Archipelago, and the last reaction takes place without the aid of heat by the even in the Philippines. Their resinous juice is used mere contact of the silver oxide with the hypochlorite very generally as varnish, hence the name “wood solution ; it is not a sudden reaction, because the oil.” It is hardly probable that they all yield a resin particles of silver oxide becoming coated with chemically and physically identical. The author has chloride are protected from further change until found that the oil distilled by him from undoubtedly this coating is removed, and consequently the action true dipterocarpus balsam is dextrogyre, whilst Weris progressive and gradual. The other product of ner, who first examined Gurgun balsam, in 1862, this reaction being ozone, the well-known characters speaks of it as lævogyre. In all the specimens of this form of oxygen would fully account for examined by the author to the present time, howdamage of the kind described being produced when ever, he has found the colour reaction constant. hypochlorite solution is used by laundresses in Another possible ground for failure in obtaining washing linen marked with silver oxide, for in the reaction is its confusion with other liquids addition to the bleaching action of ozone it corrodes used for similar purposes. The balsam obtained most organic substances, and by its action upon the from Hardwickia pinnata, Roxb., a leguminaceous fibre of linen would produce effects such as those plant, is used in Southern India in the same medical above described. The progressive character of the cases as copaiva balsam ; but an authentic specimen damage and the connection between its extent and in the author's possession is not fluorescent like the number of times the linen has been washed, Dipterocarpus balsam, and dissolved in carbon bi. are also circumstances which favoured the conclusion sulphide gives only a yellow colour with the acid that the damage was caused by the use of bleaching mixture. The author does not know, however, that powder in washing the linen.
it is ever there called “wood oil." In order to test this conclusion some of the articles A fat oil, used in enormous quantities in Eastern were dipped into a solution of bleaching powder, Asia for paint and varnish, and also as a drastic and it was found that when a sufficiently strong medicine, and very generaily called “wood oil,” is solution was used the linen presented the appear- obtained from the seeds of Aleurites cordata, Muller ance of having had pieces corresponding to the ink (syn. Dryandra cordata, Thunb., Elaeococca Vernicia, marks cut out with a sharp steel punch. With a Sprgl., E. verrucosa, A. Juss.), a euphorbiaceous tree. weak solution the results were not so marked, but The tree is common in China and Japan, of very when the action was continued long enough the characteristic appearance, and is known in China as fibre of the linen was rendered so weak at the the “ tung tree. The oils from the seeds of Ricinus marked places that with a very slight strain the and Croton Tiglium differ in chemical properties and articles treated in this way presented all the charac- physiological action from most known oils ; how far ters of damage shown by the linen after it had passed such peculiarities occur principally in the Euphorseveral times through the hands of the laundress. biacea is a question that yet requires answering.
Analytical Laboratory, 106, Fenchurch Street, E.C. | That the “wood oil” from the Tung tree is a fat