const byte Arrayl = 24 ; // nombre de row  ...
const byte ArrayC = 2;   // nombre de column

float tempHistory[Arrayl][ArrayC] =
{
  { 100.0 , 300000.0 },
  { 200.0 , 500000.0 },
  { 300.0 , 600000.0 },
  { 400.0 , 900000.0 },
  { 500.0 , 300000.0 },
  { 600.0 , 200000.0 },
  { 700.0 , 800000.0 },
  { 800.0 , 900000.0 },
  { 900.0 , 400000.0 },
  { 1000.0, 500000.0 },
  { 1100.0, 123456.7 },   // <--
  { 1200.0, 300000.0 },
  { 1300.0, 800000.0 },
  { 1400.0, 700000.0 },
  { 1500.0, 700000.0 },
  { 1600.0, 900000.0 },
  { 1700.0, 800000.0 },
  {   18.3, 200000.0 },   // <--
  { 1900.0, 400000.0 },
  { 2000.0, 700000.0 },
  { 2100.0, 300000.0 },
  { 2200.0, 600000.0 },
  { 2300.0, 500000.0 },
  { 2400.0, 500000.0 },
};

void setup() 
{
  Serial.begin(9600);
  Serial.println( "The sketch has started");
}

void loop()
{
  float minimumFirst = MinDataTemp( 0);   // the parameter is the selected column
  Serial.print( minimumFirst);
  float minimumSecond = MinDataTemp( 1);   // the parameter is the selected column
  Serial.print( ", ");
  Serial.print( minimumSecond);
  Serial.println();

  delay( 3000);
}

float MinDataTemp( int selectedColumn)
{
  float minimum = tempHistory[0][selectedColumn];
  
  for( auto a:tempHistory)   // global array does probably not need the &
  {
    if( a[selectedColumn] < minimum)
    {
      minimum = a[selectedColumn];
    }
  }
  return( minimum);
}