The principles  as civil proceedings and the topic is now run by  it goes on and that mainly deals with criminal material and then one can pick it up at paragraph thirty two er seventeen  when er  the authors addressed themselves to to civil proceedings  er and that er following passage deals with effects of the civil evidence act  and the relevant procedures  and then moving on my Lord to er  to in fact, thirty two thirty nine on page eighty hundred and twenty nine  the  expert has furnished the judge or jury with the necessary scientific criteria for testing the accuracy of her conclusion so that to enable the judge or jury to perform their own independent judgement by the application of these criteria to the facts proved in evidence.