3. _Zinc chloride_, 40 p.ct. solution. Both the natural silks and l.u.s.tra-celluloses are attacked at 100, and on raising the temperature the further actions are as follows: China silk is completely dissolved at 110-120; Tussah silk at 130-135; the collodion products at 140-145; the Pauly product was again most resistant, dissolving at 180.

4. _Alkaline cupric oxide_ (glycerin) solution was prepared by dissolving 10 grs. of the sulphate in 100 c.c. water, adding 5 grs.

glycerin and 10 c.c. of 40 p.ct. KOH. In this solution the China silk dissolved at the ordinary temperature; Tussah silk and the l.u.s.tra-celluloses were not appreciably affected.

5. _Cuprammonium solution_ was prepared by dissolving the precipitated cupric hydrate in 24 p.ct. ammonia. In this reagent also the China silk dissolved, and the Tussah silk as well as the l.u.s.tra-celluloses underwent no appreciable change.

6. _An ammoniacal solution of nickel oxide_ was prepared by dissolving the precipitated hydrated oxide in concentrated ammonia. The China silk was dissolved by this reagent; Tussah silk and the l.u.s.tra-celluloses entirely resisted its action.

7. _Fehling's solution_ is a solvent of the natural silks, but is without action on the l.u.s.tra-celluloses.

8. _Chromic acid_--20 p.ct. CrO_{3}--solution dissolves both the natural silks and the l.u.s.tra-celluloses at the boiling temperature of the solution.

9. _Millon's reagent_, at the boiling solution, colours the natural silks violet: the l.u.s.tra-celluloses give no reaction.

10. _Concentrated nitric acid_ attacks the natural silks powerfully in the cold; the l.u.s.tra-celluloses dissolve on heating.

11. _Iodine solution_ (I in KI) colours the China silk a deep brown, Tussah a pale brown; the celluloses from collodion are coloured at first brown, then blue. The Pauly product, on the other hand, does not react.

12. _Diphenylamine sulphate._--A solution of the base in concentrated sulphuric acid colours the natural silks a brown; the collodion 'silks'

give a strong blue reaction due to the presence of residual nitro-groups. The Pauly product is not affected.

13. _Brucin sulphate_ in presence of concentrated sulphuric acid colours the natural silks only slightly (brown); the collodion 'silks' give a strong red colouration. The Pauly product again is without reaction.

14. _Water._--The natural silks do not soften in the mouth as do the l.u.s.tra-celluloses.

15. _Water of condition_ was determined by drying at 100; the following percentages resulted (a). The percentages of water (b) taken up from the atmosphere after forty-three hours' exposure were:

(a) (b) China (raw) silk 7.97 2.24 Tussah silk 8.26 5.00

l.u.s.tra-celluloses:

Chardonnet (Besancon) 10.37 5.64 " Spreitenbach 11.17 5.77 Lehner 10.71 5.97 Pauly 10.04 6.94

16. _Behaviour on heating at 200._--After two hours' heating at this temperature the following changes were noted:

China silk Much discoloured (brown).

Tussah silk Scarcely affected.

l.u.s.tra-celluloses:

Chardonnet Converted into a blue-black charcoal, retaining the Lehner form ofthe fibres.

Pauly A bright yellow-brown colouration, without carbonisation.

17. The _losses of weight_ accompanying these changes and calculated per 100 parts of fibre dried at 100 were:

China silk 3.18 Tussah silk 2.95

l.u.s.tra-celluloses:

Chardonnet 33.70 Lehner 26.56 Pauly 1.61

18. _Inorganic const.i.tuents._--Determinations of the total ash gave for the first five of the above, numbers varying from 1.0 to 1.7 p.ct. The only noteworthy point in the comparison was the exceptionally small ash of the Pauly product, viz. 0.096 p.ct.

19. _Total nitrogen._--The natural silks contain the 16-17 p.ct. N characteristic of the proteids. The l.u.s.tra-celluloses contain 0.05-0.15 p.ct. N which in those spun from collodion is present in the form of nitric groups.

The points of chemical differentiation which are established by the above scheme of comparative investigation are summed up in tabular form.

_Methods of dyeing._--The l.u.s.tra-celluloses are briefly discussed. The specific relationship of these forms of cellulose to the colouring matters are in the main those of cotton, but they manifest in the dye-bath the somewhat intensified attraction which characterises mercerised cotton, or more generally the cellulose hydrates.

_Industrial applications_ of the l.u.s.tra-celluloses are briefly noticed in the concluding section of the book.

FOOTNOTES:

[3] With these products it is easy to observe that they have a definite fusion point 5-10 below the temperature of explosion.

SECTION III. DECOMPOSITIONS OF CELLULOSE SUCH AS THROW LIGHT ON THE PROBLEM OF ITS CONSt.i.tUTION

UEBER CELLULOSE.

G. b.u.mCKE und R. WOLFFENSTEIN (Berl. Ber., 1899, 2493).

(p. 54) _Theoretical Preface._--The purpose of these investigations is the closer characterisation of the products known as 'oxycellulose' and 'hydracellulose,' which are empirical aggregates obtained by various processes of oxidation and hydrolysis; these processes act concurrently in the production of the oxycelluloses. The action of hydrogen peroxide was specially investigated. An oxycellulose resulted possessing strongly marked aldehydic characteristics. The authors commit themselves to an explanation of this paradoxical result, i.e. the production of a body of strongly 'reducing' properties by the action of an oxidising agent upon the inert cellulose molecule (? aggregate) as due to the _hydrolytic_ action of the peroxide: following Wurster (Ber. 22, 145), who similarly explained the production of reducing sugars from cane sugar by the action of the peroxide.

The product in question is accordingly termed _hydralcellulose_. By the action of alkalis this is resolved into two bodies of alcoholic (cellulose) and acid ('acid cellulose') characteristics respectively.

The latter in drying pa.s.ses into a lactone. The acid product is also obtained from cellulose by the action of alkaline lye (boiling 30 p.ct.

NaOH) and by solution in Schweizer's reagent.

It is considered probable that the cellulose nitrates are hydrocellulose derivatives, and experimental evidence in favour of this conclusion is supplied by the results of 'nitrating' the celluloses and their oxy- and hydro- derivatives. Identical products were obtained.

_Experimental investigations._--The filter paper employed as 'original cellulose,' giving the following numbers on a.n.a.lysis:

C 44.56 44.29 44.53 44.56 H 6.39 6.31 6.46 6.42

was exposed to the action of pure distilled H_{2}O_{2} at 4-60 p.ct.

strength, at ordinary temperatures until disintegrated: a result requiring from nineteen to thirty days. The series of products gave the following a.n.a.lytical results:

C 43.61 43.61 43.46 43.89 44.0 43.87 43.92 43.81 H 6.00 6.29 6.28 6.26 6.13 6.27 6.24 6.27

results lying between the requirements of the formulae:

5 C_{6}H_{10}O_{5}.H_{2}O and 8 C_{6}H_{10}O_{5}.H_{2}O.

Hydrazones were obtained with 1.7-1.8 p.ct. N. Treated with caustic soda solution the hydrazones were dissolved in part: on reprecipitation a hydrazone of unaltered composition was obtained. The original product shows therefore a uniform distribution of the reactive CO- groups.