328 BLOTTING PAPER MODELS [ CH. X 



io/<X IOO=IOOO,M or i millimeter, i millimeter blotting paper is 

 used and every section of the series is drawn. 



(2) If the blotting paper were only y 9 ^ mm. thick it would be 

 simpler to make the model 90 times the size of the original. If, 

 however, one wished the magnification to be 100, it could be 

 accomplished thus : Each section in the series should be repre- 

 sented by i mm. or iooo/* in thickness. But if one uses blotting 

 paper of f^ mm. thickness or goo/u, there is a loss of zooyw for each 

 section and for 9 sections there would be a loss of goo/* or the 

 thickness of a sheet of the blotting paper. To remedy this one 

 uses 10 sheets of blotting paper for 9 sections. This keeps the 

 model in true proportion. In practice each of the sections is drawn 

 upon one sheet except one of them and for that two sheets of the 

 blotting paper are united and the sections drawn upon the double 

 sheet. 



494. General Rule for the Use of Blotting Paper. 

 Divide the thickness by which each section is to be represented in the 

 model by the thickness of one sheet of the blotting paper available. 

 The quotient shows the number of sheets or the fraction of a sheet 

 required for each section. 



If a quotient is a mixed number reduce it to a fraction. The 

 numerator represents the number of sheets required and the denom- 

 inator the number of sections to go with the sheets. 



Examples : (a) With a series of 10/1 sections to be modeled 

 at 100 enlargement each section of the series must be represented in 

 the model by a thickness of io/*X ioo=iooo/< or i millimeter. If 

 one uses millimeter or looo/u paper then iooo/t-7-iooo/<= T , and one 

 must use i sheet for i section. 



(b) With a series of 10/1 sections to be made into a model 100 

 times enlarged, and with blotting paper of T 9 7 mm. or 900/1 thick- 

 ,ness, each section must be represented by iojwX 100=1000^1. If the 



blotting paper is goo/* thick, then it requires for each section : 

 1000-1-900=1^ sheets of paper or y sheets for one section or 10 

 sheets for 9 sections, that is a double sheet for one of the nine 

 sections. 



(c) With a series cut i5/<, for a 50 fold model. Each section is 

 represented by a thickness of 1 5/<X 50=750/4. If one uses r mm. 

 or loco/* blotting paper then each section requires j 50 -^- 



