210 REPORT— 1859. 



The measures should be of glass, graduated, the pint and half pint into 

 ounces, the ounce measure into drachms, and the drachm measure into 

 minims ; they shonld be rather long in proportion to their width. 



The Florence oil-flasks, which can be obtained for a trifle at any oil 

 warehouse, will be found to answer every purpose, nearly as well as the more 

 expensive German flasks. They must be cleansed thoroughly from the 

 adhering oil ; this may be done by boiling in them, over the gauze gas-burner, 

 a strong solution of ordinary washing soda, and afterwards well rinsing out 

 with water. 



18. It will be found indispensable, where there are many operations going 

 on at the same time, and many different sheets of paper in various stages of 

 progress, to have a separate box or division to hold the paper in each of its 

 stages. The plan I have found most convenient, is to obtain several mill- 

 board boxes, the fronts of which will fall flat when the lid is lifted up, 

 similar to those used by stationers for holding letter paper, &c. : they can 

 be made to hold two or three piles of sheets side by side. They may be 

 obtained from M. Rousseau, 352 Strand, London. 



The scales and weights need not be of any great accuracy. A 6-inch 

 beam capable of turning to half a grain, when loaded with 500 grains in 

 each pan, will be all that is requisite : the pans must be of glass, and the 

 weights should consist of a set of grain and a set of drachm weights. 



A sponge will be found useful for wiping up any of the sol ul ions that 

 may have been spilt on the bench. Solid glass stirring rods of about the 

 thickness of a quill, and six or eight inches long, and a small Wedgewood 

 pestle and mortar, are of great service in many of the operations. 



Stoppered bottles should be employed for all the solutions; and too 

 much care cannot be taken to label each bottle accurately and distinctly. 



19. Besides the above apparatus, the following materials and chemicals 

 are requisite. A rough estimate is also given of their relative consumption 

 in three months: — Photographic paper, 270 sheets, or 112 square feet; four 

 pounds of wax ; three ounces of iodide of potassium ; three ounces of 

 bromide of potassium ; four ounces of nitrate of silver ; two ounces of glacial 

 acetic acid ; four ounces of gallic acid ; one pint of alcohol ; seven pounds of 

 hyposulphite of soda ; half a pound of cyanide of potassium ; half a pint of 

 concentrated nitric acid ; eighteen gallons of distilled water. 



20. The selection of a good sample of paper for the basis on which the 

 sensitive material is to be formed is of great importance, as any imper- 

 fection will be a source of annoyance in every stage of the process, and will 

 hardly fail to show itself on the finished picture. The paper, which from 

 numerous experiments I have found to be superior to any other, is that 

 known as Canson's thin photographic paper. This is manufactured with 

 care, and is in general very uniform in quality. 



It will be found by far the most advantageous plan, when used on a scale 

 like the present, to order it of some wholesale stationer cut to the requisite 

 dimensions. The size of the sheets in use here is 4-f inches by \2\lj inches*. 

 Hitherto Messrs. Hallifax and Co., 319 Oxford Street, have supplied us with 

 the paper of this size. 



21. I am indebted to Mr. Barclay of Regent Street, wax bleacher, for 

 much valuable information concerning wax and its adulterations, and for 



* This is a most inconvenient size, as it involves the cutting of more than one-third of 

 the paper to waste. The admirably ingenious arrangement of Mr. Ronalds was not made 

 with the view of employing Canson's paper, or it would doubtless have been contrived t 

 accommodate sheets of a size which could be cut with less waste, such as 4^ by 13 inches 

 or 4f by 11£ inches. 



