APPENDICES 



I. MlCKOSCOPlC AND SPECTROSCOPIC STANDARDS OF 

 MEASUREMENTS 



Micron (1 fi = TT) Viy millimetre (lO* 3 mm.) = 0-000039 inch. 

 Micro-millimetre (1 /JL/J) = roW micron = 1 millionth of a 



millimetre. 

 Tenth-metre = 01 = 10~ 10 metre. 



II. WEIGHTS AND MEASURES 



The photographic formulae have in most instances in this 

 book been given in metric measures, but in certain cases for 

 convenience and as a matter of custom the English standards 

 have been used. The advantage of the metric system is so 

 obvious as to need no recommendation here. 



Metric Unit of Weight is the gramme = 15'4 grains. 



Decigramme = T \j gramme = (H grm. = 1*54 grains. 



Centigramme = TO gramme = 0*01 grm. = 0*154 



Milligramme = TTHJO gramme = 0*001 grm. = 0*015 



Kilogramme = ]000 grammes = 1 kilo. 



Millimetre (mm.) = mVo metre = 0*03937 inch. 



Centimetre (cm.) = TIJ metre = 0*3937 



Metre (m.) = 39*37 inches. 



Inch = 25*4 millimetres. 



Cubic centimetre (c.c.) = T oVo 'itre = 16 minims (approximate). 



Litre = 1000 c.o. = 35 oz. 



Ounce = 28*35 grammes. 



305 x 



