I see Pete posted while I was writing. We both have the same recommendation, so it must be correct 
see Nick Gammon's tutorial on i2c Gammon Forum : Electronics : Microprocessors : I2C - Two-Wire Peripheral Interface - for Arduino
The way I interpret the first scope trace (Sending Data) is that wire.beginTransmission(7 bit address) appends the 0 write bit.
I need to send an ad hoc message to a sensor to tell it to wake up and measure, this requires the communication contains only the slave address and the WRITE bit (0) sent by the master
Try
Wire.beginTransmission(7 bit address);
Wire.endTransmission();
Wire.requestfrom(7 bit address address, n);//ask for n bytes