850 



REPORT — 1898. 



Cannabino-lactone, when oxidised -witli potassium permanganate, is 

 almost quantitatively into cannabino-lactonic acid, Cj,H,,jO,, which crystal 



, is converted 

 miiiusL ij uiiu Lii iiLi \ ci_> liiLu v-aiiiiauiiiu-iii»^tvjijiv^ ui^n^, 1-yj J AAjijv-' (, »» j-iiv>ii *,xy ST anises iioni 

 water in magnificent colourless needles, melting at I'OS'' C, and which by potash 

 fusion under suitable conditions gives a quantitative yield of isophthalic acid. 

 If, now, we trace the relationships backwards, we are forced to the following con- 

 clusions: — 



Isophthalic acid =CgHg04 



Cannabino-lac- 

 tonic acid . 



1 



Cannabino-lac- 

 tone . . . 



= C„H,A 



Oxycannabin . =CjjH]i(NO.,)Oo = 

 = Nitro-cannabino-lactone. 



/CO^H 

 = C,HX /CO ^ J »w-Carboxy 



C3H. I I phenyl-butyro 



\0 [_ lactone. 



/CO _ J m-Tolyl- 



/Nitro-m-Tolyl- 

 \ butyro-lactone. 



/CH3 I 



C,H. I I butyro-laetone 



There are three possible m-Tolyl-butyro-y-lactones, none of which is at 

 present known. Further research must show which of these is identical v/ith 

 cannabino-lactone, and also the position of the nitro group in oxycannabin. 



12. The Action of Certain Substances on the Undeveloped Photographic 

 Image. By C. H. Bothamley, F.IC, F.C.S. 



It has been known for some time to practical photographers that just as there 

 are certain substances that have the power of ' fogging ' or producing a develop- 

 able image on photographic plates, so there are substances that have the power of 

 destroying the latent image produced by the action of light. Several years ago 

 a plate which the author had fully exposed on a landscape was wrapped in three 

 or four thicknesses of tissue paper, and outside this some orange paper with 

 printed matter on the outer surface, the whole being enclosed in a metal box with 

 other plates. After some months the plate was developed, and it was found that 

 on the negative there was an image of the printed matter on the outside of the 

 paper, this image being much less opaque than the surrounding parts of the 

 negative. It followed that the printer's ink had given oft' some vapour which had 

 passed through the several thicknesses of paper, and destroyed the developable 

 image produced by the action of light. Somewhat later it was found that in the 

 case of several exposed plates that were left in the dark slides for some weeks 

 the material composing the hinges of the slides had emitted some vapour that had 

 undone the work done by light, the hinges being represented by almost transparent 

 bands in the negatives. Abney showed long ago that hydrogen peroxide wiU 

 destroy the image produced by light, and the author finds that the vapour of the 

 peroxide has the same effect if allowed to act for sufficient time. It is probable, 

 therefore, that effects such as those just described are due to hydrogen peroxide 

 formed in the slow oxidation of the particular substance. Turpentine vapour, 

 which produces hydrogen peroxide when oxidised by moist air, also completely 

 destroys the developable image produced by light. Some evidence has been 

 obtained that in the earliest stages of the action the reducing effect of hydrogen 

 peroxide, as observed by Russell, is added to the effect produced by light, but 

 with longer time the hydrogen peroxide destroys the developable image so pro- 

 duced. The general conclusion is that hydrogen peroxide, when it acts in small 

 quantities or for a short time, acts as a reducer and produces a developable image 

 on the photographic plate ; but when it acts in a more concentrated form, or for a 

 longer time, it acts as an oxidising agent and destroys the developable image. 



