The datasheet doesn't show the ability to do sequential reads. I would read the two registers separately:
Wire.beginTransmission(66); // transmit to device #112
Wire.write(byte(254)); // sets register pointer to angle MSB
Wire.endTransmission(); // stop transmitting
Wire.requestFrom(66, 1); // request 2 bytes from slave device #112
if(Wire.available())
reading = Wire.read(); // receive high byte
reading <<= 6; // shift MSB to be bits 6-13.
Wire.beginTransmission(66); // transmit to device #112
Wire.write(byte(255)); // sets register pointer to angle LSB
Wire.endTransmission(); // stop transmitting
Wire.requestFrom(66, 1); // request 2 bytes from slave device #112
if(Wire.available())
reading |= (Wire.read() & 0x3F); // receive low six bits
Serial.println(reading); // print the reading
delay(300); // wait a bit since people have to read the output :)