the electrostatic detector is arranged in the iron in such a way that it is faces the fabric when the iron is moved over the fabric . fig1 shows diagrammatically an iron 30 provided with an electrostatic detector 35 arranged at the back of the soleplate 31 of the iron . the electrostatic detector is shown in fig2 a which shows a metal electrode 40 which is electrically connected to a high - impedance electrostatic voltmeter circuit 41 . the electrode 40 , which is electrically insulated by means of an insulator tube 46 , is arranged in a shielding 42 in order to ensure that the measurement is not disturbed . a coaxial connection 43 may be provided between the electrode 40 and the voltmeter circuit 41 . the electrode 40 is arranged in the iron so as to be situated at a small distance from the fabric 45 . thus , the amount of the electrostatic charge generated at the surface of the fabric by the movement of the soleplate of the iron can be measured capacitively by means of the electrode 40 . between the electrode 40 and the fabric 45 a capacitance c 0 exists . between the electrode 40 and the shielding 42 a capacitance c 1 exists . the electric signal appears as a signal whose amplitude varies in the rhythm of the movement of the iron on the fabric . in order to avoid that the electrostatic charges accumulate to the extent that they saturate the input stage of the electrostatic voltmeter circuit 41 , which would prevent signal fluctuations from being measured , it is possible to carry out zero resets . for this purpose there is provided a predetermined electrostatic - charge threshold which should not be exceeded . when this threshold is reached the electrode 40 should be reset to zero : or by arranging a permanent leakage resistance across the capacitance c 1 , or the capacitive bridge is shown in fig2 b . by measuring the electrostatic potential v 1 across the capacitance c 1 it is possible to determine the magnitude of the charges on the fabric . by measuring v 1 , the values c 0 and c 1 being laid down by the construction , it is possible to determine the electrostatic character of the fabric by experiment . by way of example comparative values ( expressed in arbitrary units ) are given for several fabric types . ______________________________________ cotton 1 to 5 viscose 1 to 5 acetate 15 to 20 polyester 18 to 24 acrylic 15 to 20 nylon 14 to 18 wool 18 to 24 silk 14 to 20______________________________________ it is to be noted that most fabrics requiting comparatively low ironing temperatures exhibit the most pronounced electrostatic character . it is possible to increase the amount of generated electrostatic charges by providing the iron with an element made of an insulating material and arranged on the iron to generate electrostatic charges by frictional contact as the iron slides on the fabric . it may be formed by , for example , a plate 64 ( fig3 ) arranged in the proximity of the electrostatic detector 35 . the plate 64 may partly or wholly surround the electrostatic detector and have an l - shape or a circular shape . the plate can be made of , for example , teflon , glass , enamel , kapton . when the degree of humidity of the fabric is too high the generation of electrostatic charges diminishes and may even cease . the rhythm in which the electrostatic charges vary is then measured by means of a humidity detector , which measures the electrical resistance of the fabric between two contact electrodes . thus , an advantageous embodiment is obtained in that the two detectors are made to operate in a complementary fashion . fig3 is a diagrammatic underneath view of an iron 30 provided with a humidity detector 60 and an electrostatic detector 35 . the humidity detector 60 comprises two electrodes 62a , 62b , which preferably have a rounded shape , for example hemispheric , to slide easily on the fabric . suitable electrodes are , for example , stainless steel electrodes of 5 mm to 10 mm diameter . these electrodes may be arranged on an elastic base 64 for a good contact with the fabric without leaving any traces . these electrodes are connected to measurement means which determine the rhythm of the variations of the electrical resistance of the fabric . if the electrical resistance is low the fabric is moist . if this resistance value is high the fabric is dry . the electrodes are accommodated in recesses 63a , 63b formed in the base 64 . when the amount of generated electrostatic charges is to be increased the element to be provided may be constituted by said base 64 in that it is made of an electrically insulating material , for example , teflon , glass , enamel , kapton . the temperature resistance of the material of the base should be adequate to enable it to be brought into contact with more or less warm fabrics without degradation of the material . in order to ensure that the electrostatic detector 35 can operate in various directions of movement of the iron the base 64 may partly or wholly surround the measurement electrode 40 . a suitable shape is , for example , an l - shape or a circular shape . fig4 is a diagram of an electrical resistivity - measurement circuit . the electrodes 62a , 62b , which are in contact with the fabric 45 , are connected to an electrical power supply 90 and to a circuit 89 for measuring the electric current i in the circuit . fig5 a , 5b , 5c and 5d are curves representing resistance variations dr and electrostatic - charge variations dq during a dehumidifying operation for an iron as shown in fig3 . when the iron is applied and subsequently moved in the direction of its front tip with a moderately warm soleplate the humidity detector 60 will meet fabric areas which become increasingly dry ( over the soleplate length of the iron ). this yields curves a and c for cotton and curves b and c for acrylic fabrics as a function of the degree of drying s . the curves d and d relate to the electrostatic - charge variations dq . the units which are used are arbitrary . when the resistance becomes high the amount of electrostatic charge increases in relation to the nature of the fabric . in practice , the fabrics never have a constant humidity , which results in fluctuations of the signal as a function of the movements of the iron . fig6 shows a curve representing the variation of an output signal i ( d ) as a function of the displacement d of the iron . it is both representative of a signal obtained from the electrostatic detector and from the humidity detector . the signal consists of a sequence of halfwaves of variable amplitudes . to detect the movement the number of rises and / or falls of the signal in a predetermined time interval is calculated . these halfwaves of the signal are caused by the ironing movements . fig7 shows an example of the circuit 89 by means of which the number of halfwaves can be determined . it comprises a capacitor c 3 and a resistor r 3 connected to an input of an amplifier 92 having a high input impedance . this circuit derives the signal i and supplies pulses upon each rising and falling edge of the signal . these pulses are subsequently counted in a counter 93 , which supplies a signal s on an output 94 when no or a very small number of pulses ( for example 1 to 3 ) have appeared within the predetermined time interval . this signal s is then used to influence the control means 96 of the iron in order to turn off the heating of the heating element 97 . the other input of the amplifier 92 may be connected to earth . the soleplate of the iron can now take the place of the electrode 62 b . the humidity detector then comprises an electrode 62 a and the soleplate 31 as the second electrode . it is also possible to extend the circuit 89 with another circuit 99 which determines the average amplitude of the signal i ( d ). ( fig8 ). this average value is then representative of the degree of humidity of the fabric . the circuit comprises a resistor r 1 connected to the input terminal 88 receiving the current i , the other end of this resistor r 1 being connected to an amplifier 91 having a high input impedance . a circuit comprising a capacitance c 2 and a resistance r 2 in parallel is arranged between the input and the output of this amplifier 91 . thus , a signal representing the average degree of humidity of the fabric appears on the output 95 . this signal can then be used for influencing the means 96 for controlling the iron , for example in order to increase the electric power dissipated in the heating element 97 in order to speed up the rate of dehumidification of the fabric .